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ANSC 2401 Lab Manual Medical Terminology Anatomy: The study of the structures of the body (the tissues and organs) and their relationships. Physiology: The study of how the body structures function. Planes of Reference Median Plane: A single plane that passes through the center of the long axis of the body (head to tail) and divides it into equal left and right halves. Sagittal Plane: Any plane parallel to the median plane. Transverse Plane: Any plane that is located at a right angle to the median plane and passes through the long axis of the body. Divides the body into cranial and caudal segments. Frontal Plane: Any plane that lies at right angles to both the medial and transverse planes. Divides the body into dorsal (back) and ventral (belly) segments. Descriptive Terminology Anterior: In front of or towards the head. (Anterior and Cranial are often interchanged.) Cranial: Pertaining to or toward the head. (Superior is often used in human anatomy.) Rostral: The anterior portion of the head, towards the nose. Posterior: Behind or towards the rear or tail. (Posterior and Caudal are often interchanged.) Medial: Pertaining to the midline, towards the middle or inside. Lateral: Lying away from the midline, towards the outside (sides). Dorsal: Upwards, towards the back. Ventral: Downward, towards the belly. Proximal: Closer to the center of the body. Distal: Farther from the center of the body. Superficial: Pertaining to or closer to the surface. Deep: Farther from the surface. Intermediate: In between. Flexion: A folding movement that decreases the angle between two bones. Extension: A movement that increases the angle between two bones. It restores the http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (1 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual body part to its anatomical position after flexion. Abduct: To move away from the median plane. Adduct: To move toward the median plane. Circumduction: A movement in a cone-shape accomplished by a combination of abduction, adduction, flexion and extension. Common Prefixes and Suffixes Hypo-: Prefix meaning below, underneath, or lower than normal. Ex. Hypodermic = below the dermis (skin) Hyper-: Prefix meaning above or higher than normal. Ex: Hypertrophy = too much grow Sub-: Prefix meaning below or under. Ex: Subcutaneous = below the skin Ad-: Prefix meaning above. Ex: Adrenal = above the kidney Intra-: Prefix meaning within. Ex: Intravenous = within the vein Endo-: Prefix meaning inner or inside. Ex: Endometrium = the inner lining of the uterus Ecto-: Prefix meaning outer or outside. Ex: Ectoderm = the outer layer of the skin Meso-: Prefix meaning middle Ex: Mesometrium = the middle layer of the uterus Poly-: Prefix meaning many or too many. Ex: Polyuria = too much (excess) urine -itis: Suffix meaning inflammation. Ex: Sinusitis = inflammation of the sinuses -philic: Suffix meaning loving or liking. Ex: Hydrophilic = water loving -phobic: Suffix meaning hating or fearing. Ex: Hydrophobic = water hating -ectomy: Suffix meaning to cut out. Ex: Tonsillectomy = removal of the tonsils -otomy: Suffix meaning to cut into. Ex: Tracheotomy = cutting into the trachea -ostomy: Suffix meaning to form an opening. Ex: Gastroduodenostomy = forming a new opening between the stomach and duodenum http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (2 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual -osis: Suffix that means condition (usually a diseased condition). Ex: Endometriosis = a condition of the inner lining of the uterus Notes Cell and Tissue Biology Organization of the Body Cell: The smallest structural unit of organisms that can be considered living. Tissue: A group of similar cells organized into a structural and functional unit. Organ: A body structure composed of several tissues grouped together in a structural, functional unit. Organ System: A group of organs organized into a structural, functional unit. Organism: Any individual living creature. It can be either unicellular or multicellular. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (3 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Cellular Structures Cell (Plasma) Membrane: A semi-permeable membrane that encloses the cytoplasm and all the cellular organelles. It separates the cell contents from the extra-cellular fluid and external environment. It is composed of a phosolipid bilayer that contains integral and peripheral proteins that help to transport nutrients and waste into and out of the cell. Cytoplasm (Protoplasm): The aqueous, gel-like substance that surrounds a cell’s organelles and is located within the cell membrane, but external to the nucleus. Organelles: Specialized parts of a cell, each with a specific function(s). They are analogous to the organs in multi-cellular animals. Nucleus: A spherical or oval organelle that contains chromosomes (the hereditary information). It’s contents are enclosed in the nuclear membrane. Nucleoplasm (Karyolymph): A gel-like fluid contained within the nucleus. Nucleolus: A non-membranous spherical body within the nucleus composed of protein, DNA, and RNA that functions in the synthesis and storage of ribosomal RNA. Chromosomes: Structures composed of genes made of DNA that are the hereditary information of the cell. The number of chromosomes varies between species. Ex: Humans have 46 (diploid) in each non-gamete cell. Human gametes (sperm and oocytes) have 23 (haploid). Endoplasmic Reticulum: A network of channels running through the cytoplasm of a cell that serves in intracellular transportation, support, storage, synthesis, and packaging of molecules. Rough: Endoplasmic Reticulum that has ribosomes attached. Ribosomes: Organelle made of tiny granules that are composed of an RNA called ribosomal RNA (rRNA). They serve as the site of protein synthesis. Smooth: Endoplasmic Reticulum that does not have any http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (4 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual ribosomes attached to it. Golgi Complex: An organelle in the cytoplasm of cells consisting of four to eight flattened membranous sacs, stacked upon one another, with expanded areas at their ends. It functions in packaging secreted proteins, lipid secretion, and carbohydrate synthesis. Mitochondria: A double-membraned organelle that plays a central role in the production of ATP. Known as the "powerhouse" of the cell. Lysosome: An organelle in the cytoplasm of a cell, enclosed by a single membrane and containing powerful digestive enzymes. Vacuoles: Membrane-bound organelle that, in animal cells, frequently functions in temporary storage or transportation. Centrosomes: A rather dense area of cytoplasm, near the nucleus of the cell, containing centrioles. Centrioles: Paired, cylindrical structures within a centrosome, each consisting of microtubules. They are arranged at right angles to each other and function in cell division. Cilia: Numerous, short, hair-like projections on the surface of some cells. They are sometimes used for movement of foreign particles over a surface. Flagellum: A hair-like, motile process on the surface of some cells used for locomotion. The only cell in higher animals bodies that have flagella are sperm. Tissue Types Epithelial Tissue: The tissue that forms glands or the outer part of the skin and lines blood vessels, hollow organs, and passages that lead externally from the body. Simple Epithelium: Single layer of epithelial tissue. Simple Squamous Epithelium Description: Single layer of flat, scale-like cells with centrally located nuclei. Location: Lines the air sacs of lungs, glomerular http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (5 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual (Bowman’s) capsule of kidneys, and inner surfaces of the membranous labyrinth and tympanic membrane of the ear. It is called endothelium when it lines heart, blood and lymph vessels and forms capillaries. It is called mesothelium when it lines the ventral body cavity and covers the viscera as part of the serous membrane. Function: Filtration, absorption, exchange, and secretion in serous membranes. Simple Cuboidal Epithelium Description: Single layer of cube-shaped cells that have centrally located nuclei. Location: Covers the surface of ovary, lines anterior surface of capsule of the lens of eyes, forms pigmented epithelium of the retina of eye, and lines kidney tubules and smaller ducts of many glands. Function: Secretion and absorption. Simple Columnar Epithelium Description: Single layer of rectangular, columnar cells that contain goblet cells in some locations and have nuclei at the bases of cells. Can be either ciliated or non-ciliated. Location: Non-ciliated – Lines the gastrointestinal tract from the cardia of the stomach to the anus, excretory ducts of many gland and gallbladder. Ciliated – Lines a few portions of the upper respiratory tract, uterine (Fallopian) tubes, uterus, some paranasal sinuses, and central canal of spinal cord. Function: Non-ciliated – Secretion and absorption. Ciliated - Moves mucus by ciliary action. Stratified Epithelium: Epithelial tissue that consists of at least two layers of cells. Stratified Squamous Epithelium Description: Several layers of cells that are cuboidal to columnar shaped in the deep layers and squamous in the superficial layers. The basal cells replace the surface cells as they are lost. Location: The non-keratinized variety lines wet surfaces such as the lining of the mouth tongue, esophagus, and parts of the epiglottis and vagina. The keratinized variety forms the outer layer of the skin. Function: Protection. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (6 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Stratified Cuboidal Epithelium Description: Two or more layers of cells in which the surface cells are cube-shaped. Location: Ducts of adult sweat glands, fornix of the conjunctiva of the eye, cavernous urethra of the male urogenital system, pharynx, and epiglottis. Function: Protection. Stratified Columnar Epithelium Description: Several layers of cells with only the superficial layer being collumnar. Location: Lines part of the male urethra, large excretory ducts of some glands, and small areas in the anal mucous membrane. Function: Protection and secretion. Transitional Epithelium Description: Resembles non-kaeratinized stratified squamous tissue, except that the surface cells are larger and have a rounded free surface. Location: Lines the urinary bladder and portions of the ureters and urethra. Function: Permits distention. Pseudostratified Columnar Epithelium Description: Not a true stratified tissue. The nuclei are at different levels and all cells are attached to the basement membrane, but not all reach the surface. Location: Line larger excretory ducts of many large glands, epididymis, male urethra, and auditory (Eustachian) tubes. The ciliated variety with goblet cells line most of the upper respiratory tract and some ducts of the male reproductive system. Function: Secretion and movement of mucus and sperm cells by ciliary action. Glandular Epithelium Exocrine Gland http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (7 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Description: Secretes products into ducts. Location: Sweat, oil, wax, and mammary glands of the skin; digestive glands such as the salivary glands that secrete into the mouth cavity and the pancreas that secretes into the small intestine. Function: Produces mucus, perspiration, oil, wax, milk, or digestive enzymes. Types: Unicellular: Single-celled glands that secrete mucus. Ex: goblet cells of the digestive and respiratory tract Multi-cellular: Many-celled glands. Simple: Single non-branched duct. Simple Tubular: Ex: intestinal glands. Simple Branched: Ex: gastric and uterine glands. Simple Coiled Tubular: Ex: sweat glands. Simple Acinar: The secretory portion is flasklike. Ex: seminal vesicle glands. Simple Branched Acinar: Ex: oil glands. Compound: Branched ducts. Compound Tubular: Ex: http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (8 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual bulbourethral (Cower’s) glands, testes, and liver. Compound Acinar: Ex: salivary Glands (sublingual and submandibular). Compound Tubuloacinar: Ex: salivary glands and pancreas. Endocrine Gland Description: Secretes hormones into the blood. Location: Pituitary, thyroid and parathyroids, adrenals, ovaries, testes, pineal, and thymus. Function: Produces hormones that regulate various body activities. Types Holocrine: Glands that accumulate a secretory product in their cytoplasm. Merocrine (eccrine): Glands that simply form the secretory product and discharge it from the cell. Apocrine: Glands that accumulate their secretory product at the apical (outer) margin of the secretory cell. Connective Tissue Embryonic Connective Tissue Mesenchyme Description: Consists of highly branched mesenchymal cells embedded in a fluid substance. Location: Under the skin and along developing bones of embryo; some mesenchymal cell are found in adult tissue, especially along blood vessels. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (9 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Function: Forms all other kinds of connective tissue. Mucous Connective Tissue Description: Consists of flattened or spindle-shaped cells embedded in a mucus-like substance containing fine collagenous fibers. Location: Umbilical cord of fetus. Function: Support. Adult Connective Tissue Connective Tissue Proper Loose (Areolar) Connective Tissue Description: Consists of fibers (collagenous, elastic, and reticular) and several kinds of cells (fibroblasts, macrophages, plasma cells, adipocytes, and mast cells) embedded in a semi-fluid ground substance. Location: Subcutaneous layer of skin, mucous membranes, blood vessels, nerves, and body organs. Function: Strength, elasticity, and support. Adipose Tissue Description: Consists of adipocytes, "signet ring" -shaped cells with peripheral nuclei. They are specialized for fat storage. Location: Subcutaneous layer of skin, around the heart and kidneys, marrow of long bones, and padding around joints. Function: Reduces heat loss through skin, serves as an energy reserve, supports, and protects. Dense Collagenous Connective Tissue http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (10 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Description: Consists of predominately collagenous fibers arranged in bundles; fibroblasts are present in rows between bundles. Location: Forms tendons, ligaments, aponeuroses, membranes around various organs, and fasciae. Function: Provides strong attachments between various structures. Elastic Connective Tissue Description: Consists of predominately freely branching elastic fibers; fibroblasts are present in spaces between the fibers. Location: Lung tissue, wall of arteries, trachea, bronchial tubes, true vocal cords, and ligamenta flava of vertebrae. Function: Allows stretching of various organs. Reticular Connective Tissue Description: Consists of a network of interlacing reticular fibers with thin, flat cells wrapped around the fibers. Location: Liver, spleen, lymph nodes, and the basal lamina underlying epithelia. Function: Forms stroma of organs; binds together smooth muscle tissue cells. Cartilage Hyaline Cartilage Description: Also called gristle; appears as a http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (11 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual bluish white, glossy mass; contains numerous chondrocytes and is the most abundant type of cartilage. Location: Ends of long bones, ends of ribs, nose, parts of larynx, trachea, bronchi, bronchial tubes, and embryonic skeleton. Function: Provides movement at joints, flexibility, and support. Fibrocartilage Description: Consists of chondrocytes scattered among bundles of collegenous fibers. Location: Symphysis of pubis, intervertebral discs, and menisci of knee. Function: Support and fusion. Elastic Cartilage Description: Consists of chondrocytes located in a threadlike network of elastic fibers. Location: Epiglottis of larynx, external ear, and auditory (Eustachian) tubes. Function: Gives support and maintains shape. Osseous (Bone) Tissue Description: Compact bone consists of osteons (Haversian systems) that contain lamellae, lacunae, osteocytes, canaliculi, and central (Haversian) canals. Location: Both compact and spongy bone comprise the various bones of the body. Function: Support, protection, storage, houses blood forming tissue, and serves as levers that act in conjunction with muscle tissue to provide movement. Vascular (Blood) Tissue Description: Consists of plasma (intercellular substance) http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (12 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual and formed elements (erythocytes, leucocytes, and thrombocytes). Location: Within blood vessels (arteries, arterioles, capillaries, venules, and veins). Function: Erythocytes transport oxygen and carbon dioxide, leucocytes carry on phagocytosis and are involved in allergic reactions and immunity, and thrombocytes are essential to the clotting of blood. Muscular Tissue Skeletal Muscle Tissue Description: Cylindrical, striated fibers with several peripheral nuclei; voluntary. Location: Usually attached to bones. Function: Motion, posture, heat production. Smooth Muscle Tissue Description: Spindle-shaped, non-striated fibers with one centrally located nucleus; usually involuntary. Location: Walls of hollow internal structures such as blood vessels, stomach, intestines, and urinary bladder. Function: Motion (constriction of blood vessels, propulsion of foods through the gastrointestinal tract; constriction of the gallbladder). Cardiac Muscle Tissue Description: Quadrangular, branching, striated fibers with one centrally located nucleus; contains intercalated discs; usually involuntary. Location: Heart wall. Function: Motion (contraction of the heart). Nervous Tissue Description: Neurons (nerve cells) consist of a cell body and processes extending from the cell body called dendrites (usually conduct impulses toward cell body) or axons http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (13 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual (usually conduct impulses away from cell body). Location: Nervous system. Function: Exhibits sensitivity to various types of stimuli, converts stimuli to nerve impulses, and conducts nerve impulses to other neurons, muscle fibers, or glands. Organs and Organ Systems: The individual organ systems and their respective organs will be covered in their own sections. Notes http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (14 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Nervous System Nervous Tissue Neuron: Nerve Cells. They are the largest and most numerous cells in the body. No two neurons are identical. Cell Body: Contains the typical cellular organelles with the exception of the centrioles. The rough endoplasmic reticulum is concentrated into structures known ad Nissl Bodies. Nucleus: After four years of age, the nucleus is unable to undergo mitosis and is therefore unable to increase or replace neurons. Dendrite: Multiple processes that are the receptor portion of the neuron and carry nerve impulses towards the cell body. Axon: A long cylindrical process that carries nerve impulses away from the cell body of the neuron. Synaptic Knobs: The buttons of the ends of the terminal branches of axon that contain synaptic vesicles (stores chemical that will be releases into the synapse). Classification of Neurons Sensory: Brings information from receptors in the periphery to the CNS. Their cell bodies are located outside the CNS. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (15 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Motor: Carry information from the CNS to the peripheral muscles, glands, or other neurons. Their cell bodies are located within the CNS, but their axons are in the periphery Interneuron: Carry information from sensory neurons to motor neurons. The entire neuron is located within the CNS. Neuroglia Cells: Cells that support, nourish, and insulate nerve cells. They replace the connective tissue that is missing in the CNS. Astrocytes: Star-shaped support cells that form membranes around the capillaries of the CNS and bring nutrients from the capillaries to the neurons. Oligodendrocyte: Wrap around the axons of nerve cells in the CNS to form myelin. These cells are smaller than astrocytes. Microglia: The smallest of the neuroglial cells of the CNS. They can migrate and act as phagocytes to remove waste products in nervous tissue. Schwann Cells: The neuroglial cells of the peripheral nervous system. They form the myelin sheath by winding around the nerve processes. Myelin: A lipoprotein sheath that increases the speed of impulse conduction and insulates the nerve from this process. Nodes of Ranvier: The unmyelinated gaps between segments of myelin sheath. Central Nervous System (CNS): The control center of the body. Brain: Contained within the skull. Telencephalon: The largest part of the brain composed of the cerebrum. Cerebrum: Divided into a right and left hemispheres that are connected by the Corpus Collosum. Carries out higher brain function. Right Hemisphere: Controls the skeletal muscles http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (16 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual on the left side of the body. Left Hemisphere: Control the skeletal muscles on the right side of the body. Cerebral Cortex: A thin layer of Gray matter composed of nerve cell bodies. Gyri (Convolutions): Numerous folds on the surface of the cerebral hemispheres. Increase the surface area of the cerebral cortex. Grooves: Depressions between the gyri. Fissures: Deep grooves. Longitudinal Fissure: Separates the cerebrum into right and left hemispheres. Transverse Fissure: Separates the cerebellum from the cerebral hemispheres. Sulci: Shallow grooves. White Matter: Myelinated nerve axons that connect the cortex to other parts of the cortex, brain, and spinal cord. Basal Ganglia (Basal Nuclei): Masses of nerve cell bodies located deep within the white matter of the cerebrum. Lobes: The functional areas of the cerebral hemisphere, named for the overlying bones. Frontal: Houses the motor area of the brain. Olfactory Bulb: A mass of gray matter on http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (17 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual the ventral side of the frontal lobe that houses the center for smelling. Occipital: Houses of the vision centers of the brain. Temporal: Houses the hearing centers of the brain. Parietal: Houses the areas associated with temperature, pressure, tough, and pain sensations. Lateral Ventricles: Two spaces, each surrounded by a cerebral hemisphere, that are filled with cerebrospinal fluid. Diencephalon: The portion of the brain stem between the cerebrum and mesencephalon and surrounding the third ventricle. Thalmus: Two oval masses consisting of mostly gray matter and connected by the interthalamic adhesion that function as the central relay center for sensory impulses to the cerebral cortex and some motor fibers from the cortex to other brain centers. All senses except smell come through the thalamus. It also interprets an awareness of pain, touch, and temperature. Hypothalamus: Located beneath the thalamus. It communicates with the thalamus, cortex, pituitary, and other parts of the brain. Through the pituitary it is the main link between the nervous and endocrine systems. Infundibulum: The stalk attaching the pituitary gland to the hypothalamus. Pituitary: Secretes hormones necessary for growth, maturation, and reproduction. It is divided into the anterior and posterior pituitary. It is also nicknamed the "master gland" Third Ventricle: A cerebrospinal fluid filled space enclosed by the diencephalon and encircling the interthalamic adhesion. Optic Chiasm: A crossover link between the two optic nerves lying anterior to the pituitary. Mammillary Bodies: Two small rounded bodies that are involved in reflexes related to the sense of smell. Mesencephalon: The midbrain. It is located between the http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (18 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual diencephalon and the pons. Rostral Colliculi: Two rounded prominences that house the visual reflex centers. Caudal Colliculi: Two rounded prominences that house the auditory reflex centers. Cerebral Aqueduct: The ventricular tube running through the midbrain that connects the third and fourth ventricles. Metencephalon: The portion of the brain that consists of the pons and cerebellum. Pons: The bulge between the midbrain and the medulla oblongata that functions as the bridge between the brain and spinal cord and different parts of the brain. The nuclei within the pons and medulla oblongata work together to regulate breathing. Cerebellum: The 2nd largest subdivision of the brain and it functions as the motor reflex center in coordinating subconscious and conscious skeletal muscle movements. Proprioceptors in muscles, tendons, and joints, vestibular receptors in the inner ear, and visual receptors in the eyes relay sensory information to the cerebellum. The cerebellum then evaluates the information and sends out motor impulses to adjust muscle actions to maintain posture and balance and coordinate muscle movements. Vermis: The central portion of the cerebellum. Lateral Masses: The indented parts of the cerebellum on either side of the vermis that form parallel ridges. Cerebellar Cortex: The thin outer layer of gray matter of the cerebellum. Abor Vitae: The white matter tracts branching into the cerebellum. Cerebellar Peduncles: Bundles of fibers that connect the cerebellum to the brain stem. Caudal Peduncles: Connect the medulla, spinal cord, and cerebellum. Middle Peduncles: Connect the cerebellum and pons. Rostral Peduncles: Connect the midbrain and http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (19 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual cerebellum. Myencephalon: The caudal portion of the brain. Medulla Oblongata (Medulla): The caudal portion of the brain stem that continues on to become the spinal cord. The cardiac reflex center controls the rate and strength of heart contractions. The vasomotor center regulates blood pressure by controlling the diameter of blood vessels. The respiratory center controls breathing rhythm. Other "non-vital" reflex centers control coughing, sneezing, swallowing, and vomiting. Pyramids: Motor tracts coming from the cerebral cortex on the ventral surface of the medulla. Fourth Ventricle: A cerebrospinal fluid filled space located between the medulla and cerebellum. Spinal Cord: The long column of nervous tissue located within the vertebral canal. It is a direct continuation of the medulla oblongata. Divisions Cervical Thoracic Lumbar Sacral Coccygeal Important Spinal Cord Parts Cervical Enlargement: An enlargement of the caudal part of the cervical and cranial part of the thoracic spinal cord. The brachial plexus emerges form here. Lumbar Enlargement: An enlargement near where the pelvic limb attaches. Conus Medularis: The tapered end of the spinal cord. Filum Termiale: The fibrous cord derived from the pia matter, which extends from the conus to the caudal vertebrae. It helps to anchor the spinal cord in the spinal canal. Cauda Equina: The "horses tail" formed by the nerve roots leaving the caudal portion of the spinal cord. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (20 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Dorsal Median Fissure: The groove extending the length of the dorsal side of the spinal cord dividing it into symmetrical lateral halves. Ventral Median Fissure: The groove extending the length of the ventral surface of the spinal cord. Gray Matter: The nerve cell bodies and synapses that form the central H-shaped pattern in the spinal cord. White Matter: The axons that run up and down the spinal cord and surrounds the H-shaped mass of gray matter. These tracts connect the brain and the various segments of the spinal cord. It is the myelin around the nerve fibers that gives it the white color. Ascending Tracts: The axons that travel up the cord and carry sensory impulses to the brain. Descending Tracts: The axons of the neurons in the brain that travel down the cord and carry motor impulses. Notes http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (21 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Special Senses (Eye and Ear) Eye: The organ of sight that consists of the eyeball and its accessory structures. Eyeball Fibrous tunic: The outer coat of the eyeball. Sclera: The fibrous tissue that gives the eyeball shape and http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (22 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual protects the inner structures. The "white of the eye". Cornea: The transparent fibrous coat that lets light into the eyeball. Vascular Tunic: The middle layer of the eyeball consisting mainly of blood vessels and smooth muscle. It supplies nutrients to the eyeball and controls the shape of the lens and size of the pupil. Choroid: A thin, dark, highly vascular membrane inside the sclera. It supplies the retina and serves to absorb light that is not reflected out of the eyeball. Tapetum: A light-reflecting layer of cells of the inner choroid. Its is only present in part of the choroid and its size varies between species in which it is present (Ex: dogs, cats, horses, ruminants). It allows for greater vision with minimal light. Its reflection of light is seen as the characteristic greenish glow of the eyes at night when a light is shined on them. Ciliary Body: The thickest portion of the vascular tunic between the choroid and the iris. Ciliary Muscle: The smooth muscle that alters the shape of the lens. Ciliary Processes: The folds on the inner surface of the ciliary body that secrete the aqueous humor. Suspensory Ligament: The ligament that attaches the lens to the ciliary body, holds the lens in position, and allows the shape to be changed due to the ciliary muscle. Iris: The colored, doughnut-shaped part of the eye that surrounds the pupil. The muscles within it react to light to increase or decrease the size of the pupil to regulate the amount of light entering the eyeball. Corpora Nigra (Granula Iridica): Several black masses at the upper and lower edges of the iris. Found only in horses and ruminants. Pupil: The central opening of the iris that allows light to enter the eyeball. Nervous Tunic (Retina): The inner coat of the eyeball that functions in image formation. It lines the caudal part of the eyeball and ends at http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (23 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual the edge of the ciliary body. This border is scalloped and is call the ora serrata. It consists of three layers of neurons. Photoreceptors: The light sensitive layer of the retina made. Rods: The dendrites that are sensitive to dim light and shapes (night vision). Cones: The dendrites sensitive to color and sharpness of vision. They are densely concentrated in the central fovea located in the macula lutea (the yellow area in the caudal part of the retina). Bipolar Neurons: The intermediate layer of the retina that receives impulses from the rods and cones and passes them along to the neuronal ganglia. Ganglion Neurons: The third layer of the retina that passes the impulse from their axons to the optic nerve. Optic Disc: The area on the retina where the axons from the ganglion neurons leave the eyeball as the optic nerve. It has no cones or rods in this area and is called the blind spot. Lens: The transparent, biconvex structure located caudal to the iris. It is arranged in layers of protein fibers (like the layers of an onion) and is part of the refractory mechanism of the eye. Interior of the Eye Anterior Cavity: Lies anterior to the lens and is divided into two chambers. Anterior Chamber: The part of the anterior cavity between the cornea and the lens. Posterior Chamber: The part of the anterior cavity between the iris, lens, and suspensory ligament. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (24 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Aqueous Humor: The watery fluid, similar to cerebrospinal fluid, that fills the anterior cavity. It is secreted by the ciliary processes into the posterior chamber, flows through the pupil to the anterior chamber and drains at the periphery of the anterior chamber into the blood. It maintains intraocular pressure. Posterior Cavity: The larger cavity that lies between the lens and the retina. Vitreous Humor: The jelly-like substance that fills the posterior cavity, maintains the shape of the eyeball, and holds the retina in place. Muscles of the Eye Intrinsic Muscles: Muscles in the interior of the eye. Pupillary Sphincter: Contracts the pupil. Pupillary Dilator: Dilates the pupil. Cilary Muscles: Control the shape of the lens. Extrinsic Muscles: Muscles outside the eyeball that move the eyeball. Superior Rectus Action: Eye looks up. Innervation: Oculomotor (III) Inferior Rectus Action: Eye looks down. Innervation: Oculomotor (III) Lateral Rectus Action: Eye rotates laterally. Innervation: Abducens (VI) Medial Rectus Action: Eye rotates medially. Innervation: Oculomotor (III) Superior Oblique http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (25 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Action: Eye rolls, looks down, and to the side. Innervation: Trochlear (IV) Inferior Oblique Action: Eye rolls, looks up, and to the side. Innervation: Oculomotor (III) Accessory Structures of the Eye Eyelids: Also called palpebrae. Two moveable folds that protect the rostral surface of the eyeball. Lateral and Medial Angles: The angles made by the joining of the upper and lower eyelids. Lacrimal Caruncles: The triangular prominence in the medial angle. Lacrimal Puncta: Openings into the lacrimal canals on the upper and lower eyelids near the median angle. Lacrimal Glands: Secrete "tears" to keep the eyeball moist, provide lubrication, and keep the eye clean and free of foreign material.. Located dorsal to the eyeball. Conjunctiva: The special mucous membrane lining the eyelid and eyeball. Palpebral Conjunctiva: Lines the inner surface of the eyelid. Bulabar Conjunctiva: Reflection of the palpebral conjunctiva onto the eyeball. Third Eyelid (Palpebra Tertia): The fold of the conjunctiva, reinforced by cartilage, located between the eyelid’s median angle and the eyeball. Retraction of the eyeball causes the third eyelid to move across and protect the eyeball. Ear: The organ of hearing and balance. Outer Ear: Consists of the pinna and the external auditory meatus. Pinna (Auricle): The fleshy appendage attached to the side of the skull by muscles and ligaments. It is very mobile and functions to catch http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (26 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual and direct sound towards the middle ear. Auricular Cartilage: The elastic framework of the pinna and external auditory meatus. Both sides are covered with skin. External Auditory Meatus: The passage from the pinna to the ear drum. Middle Ear (Tympanic Cavity): Consists of the tympanic membrane, auditory ossicles and the opening to the auditory tube. Tympanic Membrane (Ear Drum): The thin, semitransparent membrane between the external auditory meatus and the middle ear. Sound causes it to vibrate. Auditory Ossicles: The three bones extending from the ear drum to the oval window of the cochlea. They transmit and amplify vibrations of the ear drum to he oval window. Malleus (Hammer): The small bone connecting the inner surface of the tympanic membrane to the incus. Incus (Anvil): The bone between the malleus and the stapes. Stapes (Stirrup): The smallest bone in the body. It fits into the oval window. Auditory Tube (Eustachian Tube): The passageway between the middle ear and the nasopharynx. It equalizes pressure on both sides of the tympanic membrane to protect it from rupturing. Swallowing or yawning opens the auditory tube, allowing air into the middle ear. Inner Ear: The osseous and membranous labyrinth. Osseous (Bony) Labyrinth: A series of cavities in the temporal bone that are lines with periosteum. Divided into the vestibule, cochlea, and semicircular canals. Perilymph: The fluid within the bony labyrinth, surrounding the membranous labyrinth. Membranous Labyrinth: A series of tubes and sacs within the bony labyrinth. Endolymph: The fluid within the membranous labyrinth. Cochlea: The snail shell-like part of the inner ear associated with hearing. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (27 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Bony Labyrinth of the Cochlea: A spiral canal making a number of turns around a central bony core (modiolus). Scala Vestibuli: The bony canal that communicates with the vestibule, the oval window of the middle ear, and the scala tympani at the apex of the cochlea. Scala Tympani: A continuation of the scala vestibuli from the apex of the cochlea to the round window. Membranous Labyrinth: Divides the bony labyrinth into two channels – the scala vestibuli and the scala tympani and forms the cochlear duct. Cochlear Duct (Scala Media): The spiral canal extending from the base to the apex of the cochlea. It is filled with endolymph and contains the spiral organ. Spiral Organ (Organ of Corti): The organ of hearing. It consists of a series of hair cells on the inner surface of the membranous labyrinth. The bending of the free ends of the hair cells by the vibrating of the endolymph generates a mechanical signal transmitted by the cochlear branch of the vestibulocochlear nerve (VIII) to the brain where it is received as sound. Vestibule: The central expanded portion of the bony labyrinth. Membranous Labyrinth of the Vestibule: Consist of two sacs – the saccule and the utricle. Maculae: Static equilibrium receptors located perpendicular to each other in the utricle and saccule. Hair (Receptor) Cells: The receptor cells of the maculae that carry impulses to the vestibular branch of the vestibulocochlear nerve (VIII). Otolithic Membrane: A gelatinous layer over the hair cells in which they are embedded. Otoliths: Calcium carbonate crystal forming a layer over the otolithic membrane. Semicircular Canals: Three bony canals arising from the vestibule and arranged at approximately right angles to each other. Ampulla: An enlarged swelling at the end of each semicircular http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (28 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual canal. Membranous Labyrinth of the Semicircular Canals: Forms the semicircular ducts that communicate with the utricle. Crista: The receptor organ found in the ampulla of each semicircular duct. It is composed of hair cells and supporting cell. Cupula: The gelatinous mass covering the crista. Notes http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (29 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (30 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Skeletal System Osteology: The study of bones. Compact (Dense) Bone: Bone tissue with no apparent spaces in which the layers of the lamellae are fitted tightly together. Cancellous (Spongy) Bone: Porous bone tissue with a reticular of latticework structure. Usually filled with bone marrow. Parts of the Bone Diaphysis: The shaft or long main portion of the bone. Located between the epiphyses. Epiphysis: The extremities or ends of the bone. Metaphysis: The region in mature bone where the epiphyses join the diahysis. Epiphyseal Plate: The region in growing bone between the diaphysis and the epiphysis made of hyaline cartilage. It is eventually replaced with bone and becomes the metaphysis. Articular cartilage: A thin layer of hyaline cartilage that covers the epiphysis where the bone forms a joint with another bone. Periosteum: A dense, white, fibrous covering around the surface of the bone. It does not cover the area where the articular cartilage is located. Medullary (Marrow) Cavity: The space within the diaphysis that contains the fatty yellow marrow (functions in fat storage) in adults. Endosteum: A layer of osteoprogenitor cells and osteoblasts that lines the medullary cavity. It also contains some osteoclasts. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (31 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Markings on Bone Condyle: Large articular prominence. Cotyloid: A deep articular depression. Crest: A prominent border or ridge. Epicondyle: A prominence just proximal to the to a condyle. Facet: A smooth flat surface. Fissure: A narrow cleft-like opening between adjacent bones. Foramen: An opening through a bone. Fossa: A small hollow. Fovea: A shallow, non-articular depression. Groove: A long narrow furrow accommodating a vessel, nerve, or tendon. Head: A rounded articular process. Meatus: A tube-like canal through a bone. Notch: A depression at the edge of a bone. Process: Any prominent, roughened projection from a bone. Spine: A sharp, slender process. Trochanter: A large, blunt process found only on the femur. Trochlea: A pulley-shaped structure. Tubercle: A small, rounded process. Tuberosity (Tuber): A large, usually roughened process. Bone Cells Osteoprogenitor: Unspecialized precursor cells that are able to differentiate into http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (32 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual osteoblasts. Osteoblasts: Cells that participate in bone formation by secreting some organic components and inorganic salts. Osteocytes: A mature bone cell that maintains the daily activity of the bone tissue. Osteoclast: A large multi-nuclear cell that develops from a monocyte and destroys or reabsorbs bone tissue. Classification of Bones Long Bones: Bones with a greater length than width. Consist of a diaphysis and a variable number of epiphyses. Metacarpals, metatarsals, and phalanges have one, others have two and the femur has four. Short Bones: Bones that are somewhat cube-shaped and nearly equal in length and width. Flat Bones: Bones that are generally thin and composed of two more or less parallel plates of compact bone enclosing a layer of spongy bone. Irregular Bones: Unpaired bones with complex shapes that do not fit into any of the above categories. Ex: vertebra and some facial bones. Sesamoid Bones: Small bones embedded within tendons where a great deal of pressure develops. They help to reduce friction. Pneumatic Bones: Bones that contain air spaces or sinuses. Ex: frontal and maxillary bones. Axial Skeleton Skull: Comprised of the cranial and facial bones. (22 bones in humans) Cranial Bones: Bones that enclose and protect the brain. Frontal http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (33 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Parietal Temporal Zygomatic Process External Acoustic (Auditory) Meatus Occipital Occipital Condyles Jugular Process Sphenoid Ethmoid Facial Bones Nasal Paranasal Sinuses: Air-filled cavities in some cranial and facial bones that are lined by mucous membranes that are continuous with the lining of the nasal cavity. Included are the frontal, maxillary, sphenoid, palatine, lacrimal, and conchal sinuses. Maxilla Incisive: Bones that hold the upper incisors. Absent in humans. Zygomatic Temporal Process Mandible Lacrimal Palatine Inferior (Ventral) Nasal Concha Vomer Interparietal: Found only in the horse and cat. Hyoid Bone http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (34 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Vertebral Column Cervical Atlas Axis Thoracic Lumbar Sacral Lumbosacral: In birds the lumbar and sacral vertebra are fused together. Coccygeal Species Cervical Thoracic Lumbar Sacral Caudal Horse 7 18 6 5 15-20 Cattle 7 13 6 5 18-20 Sheep 7 13 6-7 4 16-18 Swine 7 14-15 6-7 4 20-23 Human 7 12 5 5 4 Cat/Dog 7 13 7 3 21-25 Parts of the Vertebrae Intervertebral Foramen Intervertebral Discs Vertebral Foramen Body Spinous Process Transverse Process Wings Articular Process Thorax Sternum http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (35 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Xiphoid Process Ribs Head Tubercle Intercostal Space Costal Cartilage Appendicular Skeleton: The bones of the limbs and their supporting girdles. Pectoral (Shoulder) Girdle Clavicle: Absent in the horse and cow. Scapula Spine Acromion Supraspinous Fossa Infraspinous Fossa Subscapular Fossa Glenoid Cavity Thoracic Limb Humerus Head Intertubercle Groove Greater Tubercle Lesser Tubercle http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (36 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Body Deltoid Tuberosity Humeral Condyle Lateral Epicondyle Medial Epicondyle Olecranon Fossa Radial Fossa Radius Head Carpal Articular Surface Ulna Olcranon Tochlear Notch Styloid Process Interosseous space Carpals Radial Intermediate Ulnar Accessory C1 C2 C3 C4 Metacarpals I: The most medial metacarpal. Absent in the horse, cow, and pig. II: Missing in the cow. Known as the medial Splint bone in the horse. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (37 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual III: Known as the Cannon bone in the horse. Fused with IV in the cow. IV: Known as the lateral Splint bone in the horse. Fused with III in the cow. Phalanges: There are generally five digits (corresponding to the fingers) that are numbered from medial to lateral, each generally consisting of a proximal, middle, and distal phalanx and a varying number of sesamoid bones. Digit I: Known as the dew claw in carnivores and only having a proximal and distal phalanx. Missing in the cow and horse. Thumb in humans. Digit II: Medial dew claw in the cow. Absent in the horse. Pointer finger in humans. Digit III: Medial "toe" in the cow. The only digit present in the horse. Index finger in humans. Proximal Phalanx: Known as the Long Pastern in the horse. Middle Phalanx: Known as the Short Pastern in the horse. Distal Phalanx: Known as the Coffin bone in the horse. Proximal Sesamoids: Located at the Fetlock joint. Distal Sesamoid: Known as the Navicular bone in the horse. Digit IV: Lateral "toe" in the cow. Absent in the horse. Ring finger in humans. Digit V: Lateral dew claw in the cow. Pinky finger in humans. Pelvic Girdle Coxal (Hip) Bones Ilium Pubis http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (38 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Ischium Acetabulum Obturator Foramen Pelvic Symphysis Pelvic Limb Femur Greater Trochanter Lesser Trochanter Medial and Lateral Condyles Femoral Trochlea Patella Trochlear Tubercle Tibia Medial and Lateral Condyles Tibial Tuberosity Fibula Lateral Malleolus Tarsals: Known as the Hock. Tibial Tarsal (Talus) Fibular Tarsal (Calcaneus) Calcanean Tuberosity: Point of the hock. Metatarsals: Same pattern as in the fore limb. Phalanges: Same as in the fore limb. Joints Fibrous Joints: Generally allow little or no movement. Sutures: Joints between the skull bones. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (39 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Syndesmosis: Unites two bones with a sheet of connective tissue. Ex: Attachment between the costal cartilage. Gomphosis: The implantation of the teeth into the jaw bones. Not a true joint because the teeth are not considered part of the skeleton. Cartilaginous Joints: Can have slight or no movement. Synchondrosis: A temporary joint of hyaline cartilage. Ex: Epiphysisal plates. Symphysis: A joint that occurs along the midline of the body. They may or may not ossify with age. Ex: Pelvic symphysis. Synovial Joint: A mobile joint characterized by its mobility, a joint cavity, articular cartilage, synovial membrane, and fibrous capsule. Joint Capsule Fibrous Layer Synovial Membrane Synovial Fluid: A viscous fluid produced by the synovial membrane to lubricate a joint, supply nutrients, and remove waste from the hyaline cartilage. Ligaments: Strong bands of white, fibrous connective tissue connecting bones to keep the joint in position. Meniscus: A plate or disc of fibrocartilage that partially or completely divides a joint cavity. Allows greater motion and less concussion. Bursa: A sac-like structure between skin and bone, tendon and bone, muscle and bone, or ligament and bone that reduces friction between the tissues. Synovial Sheath: A structure similar to a bursa that is wrapped completely around a tendon to reduce the friction between the tendon and the underlying bone. Classification of Synovial Joints: A joint can be either simple (two articular surfaces) or compound (more than two articular surfaces). http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (40 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Plane: Two flat articular surfaces allowing a simple gliding motion. Ball-and-Socket: A multi-axial joint allowing universal (all types of movement). Hinge: A joint that allows movement at right angles (flexion and extension). Pivot: A joint that allows rotation around a longitudinal axis of a bone. Ellipsoid (Condyloid): A joint formed by a oval-shaped condyle of one bone fitting into an elliptical cavity of another. This allows for flexion, extension, abduction, and adduction. Notes http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (41 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (42 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Muscular System Terminology Muscle: The contractile organs that are responsible for movements, both voluntary and involuntary, of the body parts of animals. Origin: The less movable of the muscle attachments. Insertion: The more mobile muscle attachment. Tendon: A white, fibrous, dense connective tissue that attaches muscles to bone. Epimysium: The fibrous connective tissue around muscles. Perimysium: The fibrous connective tissue that separate muscle bundles. Endomysium: The fibrous connective tissue that separates each muscle fiber. Sarcolemma: The cell membrane of a muscle fiber. Muscle Attachments Fleshy: The attachment of the muscle to the periosteum of the bone by very short tendons. It appears that muscle is attached directly to the bone. Tendinous: The attachment of spindle-shaped or pennate muscles to bones by tendons. Aponeurotic: The flat tendonous sheets associated with flat muscle (like those of the abdominal wall). http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (43 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Muscle Movement: Can be flexion, extension, abduction, adduction, rotation or circumduction. Arrangement of Muscle Fibers Parallel: The muscle bundles run parallel to each other the entire length of muscle. This arrangement allows the greatest shortening, but less strength during a contraction. Pennate: The muscle bundles are arranged to cover a tendon at an angle. This allows for stronger contractions and less shortening. Unipennate: A pennate muscle whose tendon runs along one side. Bipennate: A pennate muscle whose muscle bundles cover a tendon in two direction. Multipennate: A pennate muscle whose tendons branch inside the muscle. Sphincter: A muscle whose fibers encircle an opening. Contraction of the fibers closes the opening. Muscle of the Thoracic Limb Extrinsic Muscles of the Thoracic Limb (Shoulder): Muscles that connect the thoracic limb to the head, neck, and trunk. Superficial Muscles Brachiocephalicus Origin: Mastoid process and back of neck. Insertion: Cleidocephalicus - the skull or the neck and skull/mastoid process in carnivores. Cleidobrachialis - insertion is the humerus. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (44 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Action: Pulls thoracic limb cranially (forward) or flexes the neck and head laterally. Innervation: Accessory and axillary. Trapezius Origin: Dorsal surface of neck and spines of vertebrae from T3 to T9. Insertion: Spine of scapula. Action: Elevates thoracic limb (shoulder) and draws it forward or backward. Innervation: Accessory. Omotransversarius Origin: Distal scapular spine. Insertion: Wing of atlas. Action: Pulls the thoracic limb cranially (forward) and/or depresses and pulls the head and neck laterally. Innervation: Accessory and cervical. Latissimus Dorsi Origin: Thoracolumbar fascia. Insertion: Teres major tubercle of the humerus. Action: Flexes shoulder or draw thoracic limb caudally. Innervation: Thoracodorsal Superficial Pectoral Origin: Sternum Insertion: Humerus (lesser tubercle). Action: Adduct and retract the thoracic limb. Innervation: Pectoral. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (45 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Deep Muscles Rhomboideus Origin: Cervical part – dorsal neck and thorax. Capital part (in carnivores) – nuchal crest of skull. Insertion: Dorsal border of scapula and scapular cartilage. Action: Draws shoulder dorsocranially. Innervation: Dorsal branch of spinal nerve. Serratus Ventralis Origin: Cervical part – Transverse process of vertebrae C3 – C7. Thoracic part – ribs 1 to 7or 8. Insertion: Serrated face of scapula. Action: Raise thorax, shift weight to contralateral limb and support trunk. Innervation: Long thoracic. Deep Pectoral Origin: Sternum. Insertion: Lesser tubercle of humerus. Action: Adduct and retract the thoracic limb (flex shoulder). Innervation: Pectoral and lateral thoracic. Intrinsic Muscles of the Thoracic Limb: Muscles that have their origin and insertion on the thoracic limb bones. Intrinsic Muscles of the Shoulder and Thoracic Limb Deltoid Origin: Scapular part – spine of scapula. Acromial part (absent in pigs and horses) – acromion process. Insertion: Deltoid tuberosity. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (46 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Action: Flex shoulder. Innervation: Axillary Supraspinatus Origin: Supraspinous fossa of scapula. Insertion: Greater and lesser tubercles of the humerus. Action: Stabilize and extend the shoulder. Innervation: Suprascapular Infraspinatus Origin: Infraspinous fossa of scapula. Insertion: Greater tubercle of humerus. Action: Stabilize, flex, and extend the shoulder. Innervation: Suprascapular Subscapularis Origin: Subscapular fossa. Insertion: Lesser tubercle of humerus. Action: Adduct and extend shoulder joint. Innervation: Subscapular. Teres Major Origin: Caudal border of scapula. Insertion: Teres major tuberosity of humerus. Action: Flex shoulder. Innervation: Axillary. Teres Minor Origin: Caudal border of scapula. Insertion: Teres minor tuberosity of humerus. Action: Flex shoulder. Innervation: Axillary. Coracobrachialis http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (47 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Origin: Coracoid process of scapula. Insertion: Lesser tubercle of humerus. Action: Flex shoulder. Innervation: Musculocutaneous. Biceps Brachii Origin: Supraglenoid tubercle of scapula. Insertion: Radial tuberosity. Action: Flex elbow and extend shoulder. Innervation: Musculocutaneous. Brachialis Origin: Brachial groove of humerus. Insertion: Radius. Action: Flex elbow. Innervation: Musculocutaneous. Triceps Brachii Long Head Lateral Head Medial Head Accessory Head: Absent in horses. Origin: Long Head – caudal edge of scapula. Lateral, medial, and accessory heads – humerus. Insertion: All heads – Olecranon of ulna. Action: Extend elbow. Innervation: Radial. Anconeus Origin: Olecranon fossa of humerus. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (48 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Insertion: Olecranon of ulna. Action: Extend elbow. Innervation: Radial. Tensor Fasciae Antebrachii Origin: Lattissimus dorsi. Insertion: Olecranon of ulna and antibrachial fascia. Action: Extend elbow. Innervation: Radial. Dorsolateral Forearm (Antebrachial) Muscles Extensor Carpi Radialis Origin: Lateral epicondyle of humerus. Insertion: Metacarpus. Action: Extend carpal joint and flex elbow. Innervation: Radial. Common Digital Extensor Origin: Lateral epicondyle of humerus. Insertion: Dorsal portion of distal phalanges. Action: Extend digits. Innervation: Radial. Lateral Digital Extensor Origin: Lateral epicondyle of humerus. Insertion: Middle phalanges. Action: Extend digits. Innervation: Radial. Lateral Ulnar Origin: Lateral epicondyle of humerus. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (49 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Insertion: Proximal end of Metacarpal V. Action: Flex carpal joint. Innervation: Radial. Pronator Teres Origin: Medial epicondyle of humerus. Insertion: Medial surface of radius. Action: Pronates paw Innervation: Median Supinator Origin: Lateral epicondyle of humerus. Insertion: Radius. Action: Supinates paw. Innervation: Radial. Oblique Carpal Extensor Origin: Cranial surface of forearm. Insertion: Proximal metacarpus. Action: Extend carpus and abduct carnivore’s first digit. Innervation: Radial. Caudal Antebrachial Muscles Flexor Carpi Radialis Origin: Medial epicondyle of humerus. Insertion: Proximal metacarpus. Action: Flex carpus. Innervation: Median. Flexor Carpi Ulnaris Origin: Ulnar head – Olecranon of ulna. Humeral http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (50 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual head – medial epicondyle of humerus. Insertion: Accessory carpal bone. Action: Flex carpus. Innervation: Ulnar. Superficial Digital Flexor Origin: Medial epicondyle of humerus. Insertion: Palmar surface of middle phalanges. Action: Flex digits and carpus. Innervation: Ulnar. Deep Digital Flexor Humeral Head Radial Head Ulnar Head Origin: Humerus, radius, and ulna. Insertion: Tuberosities of distal phalanges. Action: Flexes digits and carpus. Innervation: Median and ulnar. Muscles of the Pelvic Limb Sublumbar Muscles Psoas Minor Origin: Vertebrae T13 – L5. Insertion: Body of ilium. Action: Stabilize back. Innervation: Ventral branches of thoracic and lumbar. Psoas Major Origin: Lumbar vertebrae. Insertion: Lesser trochanter of femur. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (51 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Action: Flex hip and outwardly rotate thigh. Innervation: Ventral branches of thoracic and lumbar and femoral. Iliacus Origin: Wing of ilium. Insertion: Lesser trochanter of femur. Action: Flex hip and outwardly rotate thigh. Innervation: Ventral branches of lumbar and femoral. Quadratus Lumborum Origin: Transverse process of lumbar vertebrae. Insertion: Wing of sacrum and ilium. Action: Stabilizes lumbar vertebrae. Innervation: Ventral branches of lumbar and femoral. Pelvic Muscles Internal Obturator Origin: Interior of pelvis. Insertion: Caudal surface of femur. Action: Rotate femur laterally. Innervation: Ischiatic. Gemelli Origin: Ischium. Insertion: Caudal surface of femur. Action: Rotate femur laterally. Innervation: Ischiatic. Quadratus Femoris Origin: Ischium. Insertion: Caudal surface of femur. Action: Extend hip and adduct thigh. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (52 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Innervation: Ischiatic. External Obturator Origin: Ventral surface of pubis and ischium. Insertion: Caudal surface of femur. Action: Adduct thigh. Innervation: Obturator. Muscles of the Hip and Thigh Superficial Gluteal: (absent in ruminants) Origin: Dorsal to hip joint. Insertion: Third trochanter. Action: Abduct limb of femur. Insertion: Gluteal. Middle Gluteal Origin: Wing of ilium. Insertion: Greater trochanter of femur. Action: Extend and abduct pelvic limb. Innervation: Gluteal. Deep Gluteal Origin: Body of ilium. Insertion: Greater trochanter of femur. Action: Extend and abduct pelvic limb. Innervation: Gluteal. Biceps Femoris Origin: Ischiatic tuberosity. Insertion: Patella, tibia, and calcanean tuberosity of the fibular tarsal bone. Action: Extend hip, stifle, and tarsus and flex stifle. Innervation: Ischiatic. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (53 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Tensor Fasciae Latae Origin: Tuber coxae Insertion: Lateral femoral fascia. Action: Flex hip joint and extend stifle. Innervation: Gluteal. Semitendinosus Origin: Ischiatic tuberosity. Insertion: Tibia and calcanean tuberosity of the fibular tarsal bone. Action: Extend hip and tarsus and flex stifle. Innervation: Ischiatic. Sartorius Origin: Ilium. Insertion: Medial side of stifle. Action: Flex hip and stifle. Innervation: Femoral. Gracilis Origin: Pelvic symphysis. Insertion: Medial side of stifle. Action: Adduct pelvic limb. Innervation: Obturator. Pectineus Origin: Pubis. Insertion: Femur. Action: Adduct pelvic limb and flex hip. Innervation: Obturator. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (54 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Quadriceps Rectus Femoris Vastus Lateralis Vastus Medialis Vastus Intermedius Origin: Rectus femoris – iIlium. All vastus – proximal femur. Insertion: Patella and tibial tuberosity. Action: Rectus femoris – flex hip and extend stifle. All vastus – extend stifle. Innervation: Femoral. Adductor Origin: Ventral surface of hip bones. Insertion: Femur. Action: Adduct pelvic limb. Innervation: Obturator. Semimembranosus Origin: Ischiatic tuberosity. Insertion: Femur and tibia. Action: Extend hip, flex or extend stifle. Innervation: Ischiatic. Muscle of the Crus (True Leg) Cranial Tibial Origin: Proximal tibia. Insertion: Proximal metatarsus. Action: Flex tarsus. Innervation: Fibular. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (55 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Long Digital Extensor Origin: Extensor fossa of femur. Insertion: Extensor processes of distal phalanges. Action: Extend stifle and digits and flex tarsus. Innervation: Fibular. Long Fibular Origin: Lateral collateral ligament of stifle. Insertion: Tarsal and or metatarsal bones. Action: Flex tarsus. Innervation: Fibular. Third Fibular Origin: Extensor fossa of femur. Insertion: Metatarsal bones. Action: Extend stifle and flex tarsus. Innervation: Fibular. Lateral Digital Extensor Origin: Fibula. Insertion: Lateral digit. Action: Extend digits and flex tarsus. Innervation: Fibular. Gastrocnemius Origin: Distocaudal surface of femur. Insertion: Calcanean tuberosity of the fibular tarsal bone. Action: Extend tarsus and flex stifle. Innervation: Tibial. Deep Digital Flexor Origin: Tibia and fibula. Insertion: Distal phalanges. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (56 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Action: Flex digits. Innervation: Tibial. Superficial Digital Flexor Origin: Femur. Insertion: Calcanean tuberosity of the fibular tarsal bone. Action: Flex stifle and digits and extend tarsus. Innervation: Tibial. Stay Apparatus: The mechanism that allows a horse to rest while standing without muscle fatigue. This allows a horse to instantly be able to flee. Thoracic Limb: The body weight is suspended by tendons and ligaments similar to a sling. Pelvic Limb: The pelvic limb is stabilized by the locking of the patella and the patellar ligament over the trochlear tubercle of the femur. Muscles of the Abdomen External Abdominal Oblique Origin: Lower eight ribs and thoracolumbar fascia. Insertion: Aponeurosis of the ventral midline (linea alba) and iliac crest. Action: Contraction of both sides compresses the abdomen. Contraction of one side bends the body laterally. Innervation: Branches of the T7 to T12 thoracic nerves and the iliohypogastric. Internal Abdominal Oblique Origin: Iliac crest, inguinal ligament, and thoracolumbar fascia. http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (57 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Insertion: Cartilage of last three or four ribs. Action: Contraction of both sides compresses the abdomen. Contraction of one side bends the body laterally. Innervation: Branches of the T8 to T12 thoracic nerves, the iliohypogastric, and iliolinguinal. Transversus Abdominis Origin: Iliac crest, inguinal ligament, lumbar fascia, and cartilage of last six ribs. Insertion: Xiphoid process, aponeurosis of ventral midline (linea alba), and pubis. Action: Compress abdomen. Innervation: Branches of the T8 to T12 thoracic nerves, the iliohypogastric, and iliolinguinal. Rectus Abdominis Origin: Pubic crest and pubic symphysis. Insertion: Cartilage of ribs five through seven and xiphoid process. Action: Compresses abdomen to aid in defecation, urination, forced expiration, and childbirth and flexes the vertebral column. Innervation: Branches of T7 to T12 thoracic nerves. Muscles of the Thorax External Intercostal Origin: Inferior border of above rib. Insertion: Superior border of below rib. Action: Expand thorax during inspiration. Innervation: Intercostals. Internal Intercostals http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (58 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Origin: Superior border of below rib. Insertion: Inferior border of above rib. Action: Reduce diameter of thorax during expiration. Innervation: Intercostals. Diaphragm Origin: Xiphoid process, costal cartilage of last six ribs, and lumbar vertebrae. Insertion: Central tendon. Action: Forms floor of thoracic cavity and pull caudally during inspiration to increase the length of the thoracic cavity. Innervation: Phrenic. Notes http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (59 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Cardiovascular System Blood: A liquid connective tissue that has functions in transport, regulation, and protection. Transportation: transports oxygen, carbon dioxide, nutrients from gastrointestinal tract, heat and waste from cells, and hormones Regulation: regulates pH through buffers, body temperature, water cell content Protection: protects against blood loss (clotting mechanism) and against foreign microbes and toxins (phagocytic white blood cells, antibodies, interferon) Components of Blood: composed of blood plasma and formed elements (cells and cell fragments) Blood Plasma: a straw-colored liquid that is ~ 91.5% water and ~ 8.5% solutes (mostly proteins) Formed Elements Erythrocytes (red blood cells): 99% of formed elements Contain hemoglobin, which carries oxygen and gives whole blood its red color Biconcave discs with no nuclei or other organelles Cannot reproduce or carry on extensive metabolic activity and can only live ~120 days http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (60 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual 5.4 million per mm3 of blood for males and 4.8 for females Leukocytes (white blood cells): nucleated cells, some can live for several months or years, but most only live a few days (during infection, some phagocytic WBC’s live only a few hours) Granular Leukocytes: have granules in the cytoplasm that can be seen with a microscope Neutrophils: have a nucleus with five lobes connected by very thin chromatin strands and granules stain "neutral" (a pale lilac color) with a combination of acidic and basic dyes Active in phagocytosis and ingest bacteria and dispose of dead cell matter Contain proteins that exhibit antibiotic activity against bacteria, fungi, and viruses Eosinophils: have a nucleus with two lobes connected by a strand and large, uniform granules that stain red or orange with acidic dyes Believed to release enzymes that combat histamine and other mediators of inflammation in allergic reactions Basophils: have a bilobed or irregular nucleus that is often S-shaped and the granules are round and variable in size and stain blue-purple with basic dyes Involved in hypersensitivity allergic and inflammatory reactions Agranular Leukocytes: do not have granules that can be seen with a microscope Lymphocytes: have a darkly-stained round or slightly indented nucleus T cells: attack viruses, fungi, and http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (61 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual transplanted cells, cancer cells, and some bacteria B cells: destroy bacteria and inactivate their toxins Natural Killer cells: attack a wide variety of infectious microbes and spontaneously arising tumor cells Monocytes: have a kidney-shaped or horseshoeshaped nucleus and the cytoplasm has a foamy appearance Migrate into tissues and differentiate into macrophages Clean up cellular debris and microbes following infection Thrombocytes (Platelets): 250,000 to 400,000 in each mm3 of blood Disc-shaped cells with no nuclei and many granules Help with blood clotting and live 5 to 9 days Blood Types: four different blood types result from a combination of three different alleles of the I B antigen and i A=I AI A gene. I A codes for the A antigen, I B codes for the codes for neither. or I Ai B = I B I B or I Bi AB = I A I B O = ii These blood types can be either Rh + or Rh - AB+ blood types are often called Universal Recipients O- blood types are often called Universal Donors Circulation http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (62 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Systemic Circulation: pumped by the left side of the heart Receives oxygenated blood from the right side of the heart. Pulmonary Circulation: pumped by the right side of the heart Receives deoxygenated blood from the systemic system. Blood Flow Through the Body: Left Atrium ⇒ Left Ventricle ⇒ Aorta ⇒ Systemic Arteries Þ Arterioles ⇒ Capillaries (O2 unloaded and CO2 loaded) Þ Venules ⇒ Veins ⇒ Superior Vena Cava ⇒ Right Atrium ⇒ Right Ventricle ⇒ Pulmonary Trunk ⇒ Pulmonary Arteries (to right and left lungs) Þ Pulmonary Capillaries (O2 loaded and CO2 unloaded) ⇒ Veins ⇒ Left Atrium (where it starts over) Parts of the Heart Pericardium: A triple layer sac that that surrounds and protects the heart. Fibrous Pericardium: tough, inelastic, dense, irregular, connective tissue Rests on and is attached to the diaphragm Protects the heart, prevents overstretching and anchors the heart Serous Pericardium: thinner, delicate, double layer Parietal Layer: fused to the fibrous pericardium Visceral Layer (Epicardium): adheres tightly to the heart Pericardial Fluid: between the parietal and the visceral layers http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (63 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Coronary Sulcus: external groove that separates the atria and ventricles Anterior and Posterior Sulcus: external groove that separate the right and left ventricles Interatrial Septum: internal wall that separates the atria Fossa Ovalis: an oval depression that is the remnant of the foramen ovale (opening in the fetal septum that closes soon after birth) Interventrical Septum: internal wall that separates the ventricles Trabeculae Carneae: irregular folds of the myocardium in the ventricles Atrioventricular (AV) Valves: valves between the atria and ventricles Tricuspid Valve: lies between the right atrium and ventricle (has three flaps) Bicuspid (Mitral) Valve: lies between the left atrium and ventricle (has two flaps) Chordae Tendineae: tendon-like cords that attach to the papillary muscles on the inner surfaces of the ventricles Semilunar (SL) Valves: lie between the ventricles and the vessels leaving the heart Pulmonary Semilunar Valve: lies between the pulmonary trunk and the right ventricle Aortic Semilunar Valve: lies between the left ventricle and the aorta http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (64 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Respiratory System Nose: the internal structures function to warm, moisten, and filter incoming air receive olfactory stimuli modify speech sounds External Nares or Nostrils: openings Internal Nares: openings into the pharynx Nasal Septum: vertical partition diving the nasal cavity into right and left halves Pharynx (Throat): a funnel-shaped tube that starts at the internal nares and extends to the to the larynx Common passageway for food and air Resonance chamber for speech sounds Houses tonsils, which helps eliminate foreign invaders through immune reactions http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (65 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Nasopharynx: lies posterior to the nasal cavity and extends to the soft palate Two internal nare openings, two Eustachian tube openings, and the oropharynx opening Oropharynx: lies posterior to the oral cavity and extends from the soft palate to the level of the hyoid bone Has only one opening, the one from the mouth Laryngopharynx: begins at the level of the hyoid bone and connects the esophagus and the larynx Larynx (Voice Box): a short passage that connect the larnygopharynx and the trachea Lies anterior to C4 – C6 Composed of nine pieces of cartilage (thyroid, epiglottis, cricoid, arytenoid, cuneiform, and corniculate cartilages) Thyroid Cartilage is termed the Adam’s Apple Voice Production: occurs when air passes over the vocal cords (folds of mucous membranes) If air is directed over the vocal cords, they will vibrate and send sound waves through the column of air in the pharynx, nose and mouth. The greater the air pressure, the louder the sound. The pitch is controlled by the tension on the vocal cords. Trachea (Windpipe): A tubular passage that extends from the larynx to the fifth thoracic vertebrae where it divides into the primary bronchi. Has 16 – 20 C-shaped incomplete rings of hyaline cartilage Carina: an internal ridge where the trachea divides into the right and left primary bronchi Bronchi: the right primary bronchus goes to the right lung and the left primary http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (66 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual bronchus goes to the left lung Also contain incomplete rings of hyaline cartilage Each primary bronchi divides into secondary bronchi, then to tertiary bronchi Lungs: a pair of cone shaped organs in the thoracic cavity Mediastinum: along with the heart, it separates the thoracic cavity into two distinct chambers Pleural Membrane: two layers of serous membrane that encloses and protects each lung Parietal Pleura: superficial layer of that lines the wall of the thoracic cavity Visceral Pleura: deep layer that covers the lungs themselves Right lung has three lobes, while the left has two Lobules: many small compartments associated with each bronchopumonary segment (a segment of lung supplied by each tertiary bronchi) Each lobule is wrapped in elastic connective tissue and contains a lymphatic vessel, an arteriole, a venule, and a branch from a terminal bronchi Terminal bronchioles subdivide in to microscopic branches called respiratory bronchioles Respiratory bronchioles subdivide into several alveolar ducts Numerous alveoli and alveolar sacs surround the alveolar ducts Alveoli: where the exchange of O2 and CO2 occurs Inspiration: breathing in Caused by lowering the pressure in the lungs, this is done by increasing the volume of the lungs Lung volume is increased by the contraction of the diaphragm and external http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (67 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual intercostals Expiration: breathing out Passive process that results in the elastic recoil of the chest wall and lungs (they have a natural tendency to spring back after being stretched Starts when the inspiratory muscles relax During labored breathing expiration becomes active and involves the internal intercostals and abdominal muscles Urinary System Kidneys: the smooth bean-shaped organs of the urinary system that filter the blood resulting in the production of urine. (Cattle have lobular (not smooth) kidneys and the right kidney of the horse is heart-shaped.) Located in the lumbar region of the abdomen around the last thoracic / first lumbar vertebrae. They lie behind the peritoneum in non-ruminants and hang down into the abdominal cavity in ruminants. The rumen also pushes the left kidney to the right of the median plane. The right kidney lies slightly more cranially than the left kidney with the exception of the pig, where they lie at the same level. Perirenal Fat: mass of fat surrounding the kidney that protects it and holds it in place http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (68 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Fibrous capsule: a layer of connective tissue that is loosely attached to the kidney, except at the hilus Hilus: the area where the vessels and ureters leave the kidneys Cortex: outer layer of kidney, beneath the capsule Contains the renal corpuscles and the renal tubules Medulla: inner layer of the kidney Contain ducts and nephric loops Lobes: the units of the kidney (are only visible in the cow) Renal Papilla: the apex of a kidney lobe that drips urine into the ureter Renal Pelvis: the expanded proximal end of the ureter Calyx: cup-shaped structure in pigs and cows that receives urine from the renal papilla Renal Sinus: the potential space occupied by the ureter, branches of the renal artery and vein, the lymphatic vessels, and the nerves entering the kidney Note: We will not cover the micro-anatomy of the kidney since that was covered in detail in lecture. Adrenal Glands: endocrine glands that lie cranial to the kidneys. Except in the horse they lie medial to the kidney. Ureter: the fibro-muscular tubes that carry urine from the kidneys to the urinary bladder The ureters enter the bladder at an acute (sharp) angle to allow for emptying into a full bladder and to prevent back flow. Urinary Bladder: a very distensible pouch that receives and stores urine from the kidneys When distended the bladder lies not only within the pelvic cavity but also extends into the abdominal cavity http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (69 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Urethra: the fibro-muscular tube that carries urine from the bladder for release outside the body. In males it also carries semen for ejaculation. Urine and semen are expelled separately. Notes: Digestive System Oral Cavity: the space extending from the lips to the pharynx http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (70 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Philtrum: the median cleft in the upper lip of carnivores and small ruminants Teeth: used for primarily for mastication, but also for food prehension (gathering) Gomphosis: the implantation of the teeth into the alveoli (bony sockets) of the mandible, maxilla, and incisive bones - not a true joint because the teeth are not part of the skeleton Incisors (I): the most rostral teeth embedded in the incisive (maxillary bone in humans) and the mandible bones Dental Pad: replaces the upper incisors and canines in ruminants Canines (C): the large tooth (one on each side) between the incisive and cheek teeth (premolars and molars) Premolars (P): the rostral cheek teeth Molars (M): the caudal cheek teeth Carnassial (Sectorial) Teeth: the 4th upper premolar and the 1st lower molar in dogs and cats that is used for shearing Tusks: the canine teeth of the pig Wolf Teeth: a term used to describe the rudimentary upper 1st premolar which is usually absent in horses Needle Teeth: the pigs deciduous 3rd incisors and canines that are usually "nipped" off in newborn pigs Deciduous Dentition: the "baby teeth" – they are usually smaller and fewer of them than the permanent teeth Permanent Dentition: the teeth that replace the "baby teeth" which must last throughout the animal’s life Tongue: the muscular organ in the oral cavity that aids in swallowing, food movement during mastication, vocalization, taste, temperature control (panting in dogs), and prehension of food (in species such as the cow) Contains taste-buds for gustatory function (taste) Contain papillae that serve a gustatory function and or a mechanical http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (71 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual function to direct food caudally (there are several types of papillae) Apex: the rostral free end of the tongue Root: the caudal end of the tongue that is attached to the hyoid apparatus Salivary Glands: glands that secrete saliva into the oral cavity to wet and lubricate food for swallowing Saliva: a fluid consisting mainly of water, some protein, electrolytes, and IgA antibodies Pharynx: the common passage of the digestive and respiratory systems Connects the oral cavity and the esophagus and moves food toward the esophagus through undulating muscle contractions Oropharynx: extends from the oral cavity to the epiglottis Laryngopharynx: passage for food and water from the oropharynx to the esophagus – extends from the epiglottis to the entrance of the esophagus Soft Palate: divides the naso- and oro- pharnyx Esophagus: the muscular tube that is the passage of food from the pharynx to the stomach First part of the alimentary canal Lined with cornified epithelium to protect it Lies dorsal to the trachea and ventral to the vertebrae Passes through the hiatus of the diaphragm and terminates at the cardia of the stomach Non- Ruminant (Simple or Monogastric) Stomach: single compartment stomach found in carnivores, horses, pigs, and humans Receives food (ingesta) from esophagus and stores it temporarily Secretes digestive enzymes such as pepsin and hydrochloric acid Its muscular movements mix the ingesta and enzymes and move them slowly on to the duodenum Parts of the Simple Stomach http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (72 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Greater Curvature: the long convex surface of the stomach that leads from cardia to the pylorus Lesser Curvature: the short concave surface of the stomach that extends from the cardia to the pylorus Parietal Surface: the side of the stomach in contact with the liver Visceral Surface: the side of the stomach in contact with the rest of the abdominal viscera Cardia: the part of the stomach around the esophagus – the "fixed" point of the stomach Cardiac Opening: the esophageal opening into the stomach Fundus: The blind, expanded portion of the left side of the stomach adjacent to the esophagus Body: the largest part of the stomach that extends from the cardia to the pylorus Pylorus: the distal part of the stomach that opens into the duodenum at the pyloric valve (a sphincter muscle) Ruminant Stomach: a four compartment stomach found in cows, sheep, goats, ect. Forestomach (Proventriculus): the three proximal, non-glandular compartments that consist of the rumen, reticulum, and omasum Rumen: the largest of the four compartments, filling most of the left side of the abdomen A fermentation vat for microorganisms that break down the unusable cellulose into metabolizable components Papillae: numerous mucosal projections on the interior surface a "pile rug" appearance http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (73 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Cardiac Opening: the esophageal entrance into the rumen Reticulum: the most cranial compartment located on the median plane against the diaphragm Interior has a honeycomb appearance Omasum: the spherical compartment caudal to the reticulum Is sometimes termed the "Bible" or "Book" due to the page like appearance of its muscular laminae Omasal Laminae: parallel leaf-like structures projecting into the interior from the wall Abomasum: the elongated "true stomach" that is lined with glandular tissue Pylorus: the part of the abomasum that opens into the duodenum Gastric Groove: a channel through the stomach that follows the lesser curvature of the stomach, found in all domestic species, but is of greatest importance to the suckling ruminant Suckling with the head tilted up causes the lips of the gastric groove to close, forming a tube from the cardiac opening to the abomasum. This causes milk to bypass the rumen, reticulum, and omasum and empty directly into the abomasum. This reflex disappears in adults, except in response to some liquid salts. Small Intestine: the principle site of digestion and absorption which extends from the pylorus to the large intestine Duodenum: receives ingesta from the stomach Bile and pancreatic secretions empty into the descending duodenum Jejunum: the longest part of the small intestine which extends from the duodenum to the ileum Ileum: the short terminal portion of the small intestine that empties into the large intestine Large Intestine: the portion of the digestive tract that functions to dehydrate the fecal contents by absorbing water – it includes the cecum, colon and rectum http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (74 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual The size, shape, and structures vary widely between species. Cecum: the blind diverticulum off the beginning of the colon which is the site of fermentative digestion Horse: the horses cecum is a huge comma-shaped structure occupying most of the right abdominal cavity Colon: the portion of the digestive tract that carries ingesta from the small intestine to the rectum Divided into the ascending, transverse, and descending colon Horse: has a long double horseshoe shaped loop of the ascending colon Rectum: the portion of the large intestine that lies within the pelvic cavity and extends from the colon to the anus Anal Canal: the short terminal portion of the alimentary canal that opens to the exterior as the anus Accessory Organs Liver: the largest gland in the body Secrete bile into the duodenum via the bile duct Serves to metabolize carbohydrates and fats, detoxifies the body (drugs and toxins), produces plasma proteins, inactivates polypeptide hormones, ect. Gall Bladder: a sac-like structure that stores and concentrates bile to be discharged into the duodenum Absent in the horse Pancreas: a v-shaped gland that has both an endocrine and an exocrine function Endocrine: secretes insulin and glucagon into the blood to keep sugar at a constant level Exocrine: secretes enzymes that aid in the digestion of carbohydrates, fats, and proteins http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (75 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Notes: http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (76 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Male Anatomy Scrotum: the sac-like structure that supports, protects, and regulates the temperature of the testes Made of two lobes Homologous to the Labia majora in the female The skin portion has a large number of sweat and sebaceous (oil) glands The Tunica dartos is the smooth muscle portion Testes: paired structures that are the primary sex organ of the male Produces the male gametes (spermatozoa) Produces hormones Housed within the scrotum Tunica vaginalis: an extension of the peritoneum that covers the testes Tunica albuginea testis: the outer connective tissue layer http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (77 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Parenchyma: the functional layer of the testes Contains the Seminiferous tubules Site of Spermatogenesis Makes up 80% of testis weight Germ cells (Spermatogonia): become sperm Seritoi cells (Nurse cells): form the blood-testis barrier Leydig cells (Interstitial cells): Located between the seminiferous tubules Produce testosterone Epididymis: paired convoluted tubules that transport sperm from the testes to the ductus deferens Concentrates, stores, and matures sperm Spermatic Cord: paired structures that connect the testes to the urethra Carry the nerve and blood supply to the testes Carry sperm to the urethra through the ductus derferens (vas deferens) Support the testes Temperature regulation through the creamaster muscles Ductus Deferens: paired structures that transport sperm during ejaculation and connect the epididymis to the pelvic urethra Surrounded by a thick layer of smooth muscle Ampulla: the enlarged end near the urethra Absent in the boar Urethra: single duct that transports both urine and sperm Divided into two parts Pelvic urethra Penile urethra Accessory Sex Glands: glands located along the pelvic urethra http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (78 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Contribute to fluid volume of semen Provide nutrients, buffers, and other substances necessary for sperm motility and fertility Secrete seminal plasma Vesicular Glands (Seminal Vessicles): paired, lobular gland, that looks like a "cluster of grapes" Contribute to over one-half of the total semen volume Secretes fluids to protect against shifts in pH Secretes the gelatinous material in stallion semen Prostate Gland: single gland that secretes Na, Cl, Ca, Mg Secretions cleans the urethra in the stallion Bulbourethral Glands (Cowper’s Gland): paired glands Secretions cleans the urethra in the bulls Secretes the gelatinous material in boar semen Penis: the organ of copulation in the male Used by both the reproductive and urinary systems Contains the penile urethra Sigmoid Flexure: an s-shaped bend in the penis of bulls, rams, and boars Allows the penis to be retracted completely into the body Absent in the stallion Glans Penis: the free end of the penis Shape varies depending on species Homologous to the clitoris in the female Most species have a fibroelastic penis with some erectile tissue Horse, however, has a great deal more erectile tissue which engorges with blood during sexual excitement causing the penis to extend (erection) Prepuce (Sheath): encloses the free end of the penis Homologous to the labia minora in the female http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (79 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Sperm Pathway Out of the Body: Seminiferous tubules Epididymis Ductus Deferens Pelvic Urethra Penile Urethra Temperature Control of the Testes: the testes need to be maintained 4 to 10 0F lower than normal body temperature (91-97 0F) Scrotum and Spermatic Cord Tunica dartos muscles (controls the scrotum’s surface area) Creamaster muscles (controls proximity to the body) Cold weather causes these muscles to contract decreasing the surface area and drawing the testes closer to the body Hot weather cause these muscles to relax increasing the surface area and allow the testes to swing down away from the body Sebaceous and Sweat Glands Cold weather these glands are not as active Hot weather causes these glands to become more active allowing evaporation to cool the scrotum Pampiniform Plexus The arteries that supply blood to the testes are very convoluted and pass through a pampiniform plexus of testicular veins. This allows the arterial blood entering the testes to be cooled by the venous blood leaving the testes. As the spermatic cord lengthens during hot weather, more surface area is provided for the heat exchange. Notes: http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (80 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Female Anatomy Vulva: the outermost portion of the female reproductive tract Made of two portions Labia majora – outer lips Labia minora – inner lips Vestibule: the common pathway of the reproductive and urinary tract Terminal portion of the vagina Site of the urethral opening Clitoris: erectile tissue located just inside the vulva Homologous to the glans penis in the male Contains numerous sensory nerves and increases sexual excitement in the female during copulation Vagina: copulatory organ and birth canal Site of sperm deposition in most species Contains many mucosal glands Made of highly elastic muscle and connective tissue Cervix: thick-walled, inelastic "tube" that separates the vagina the uterus Usually a single structure except in species with duplex or didelphic uteruses Prevents contamination of the uterus Serves as a sperm reservoir Shape is species specific Annular rings in cow and ewe Corkscrew in pigs Mucosal folds in mares Uterus: organ that contains the fetus during pregnancy Produces hormones http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (81 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Site of placental attachment There are several types of uteri Bicornuate: two horns, no body, one cervix, one vagina Swine and dogs Biparite: two horns, one body, one cervix, one vagina Horses, cattle, and sheep Duplex: two uteri, two cervix, one vagina Rabbits and small rodents Simplex: no horns, one body, one cervix, one vagina Humans and primates Didelphic: two uteri (each with one body and one horn), two vagina, two vulva openings (Males of these species have a forked penis.) Kangaroos, opossums, and other marsupials Oviducts (Fallopian or Uterine Tube): paired structures that connect the ovaries and uterus Transports ova and sperm Made up of several segments Fimbria: finger-like projections that surround the ovary to "catch" the oocyte when released during ovulation Infundibulum: funnel-shaped portion of the tube connected to the fimbria Ampulla-Isthmus Junction: site of fertilization Uterotubal Junction: connection site of the oviduct and uterus Ovaries: paired structures that are the primary sex organs in the female Produces the female gametes (oocytes) Produces hormones Follicles: structure that contains the oocyte Corpus luteum: the structure formed after the follicle ruptures at ovulation and produces progesterone http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (82 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (83 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Embryo/Fetal Development Terminology: Zygote: As soon as the diploid number of chromosomes is returned at fertilization, what was once and ovum and sperm are now a zygote. Embryo: From the two-cell stage until differentiation is complete the conceptus is known as an embryo. This is usually not pat day 40 in the horse or day 60 in humans. Morula: When the embryo has undergone three or four cell divisions and is at the 16 to 32 cell stage it is known as a morula. The individual cells of the morula are known as blastomeres. Blastocyst: After fluid begins to collect in the innercellular spaces and forms a cavity (called a blastocele) the embryo is known as a blastocyst. Embryoblast: The cells of the inner cell mass which are located at one pole are now called the embryoblast. Trophoblast: The outer cell mass that becomes the epithelial wall of the blastocyst is called the trophoblast. The trophoblast will eventually become part of the placenta. During the blastocyst stage the embryo hatches out of the Zona Pellucida Fetus: After differentiation has been complete and until parturition the conceptus is known as a fetus. 1st Trimester: during the first 1/3rd of pregnancy in any species is the period of when there is the largest increases in cell numbers This is time from fertilization to organogenisis http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (84 of 85) [6/10/2008 11:57:21 AM] ANSC 2401 Lab Manual Organogenisis: the differentiation and formation of the organs Nervous system is the first to begin to form but the last to complete Heart is the first organ to complete formation Heartbeat can be detected at ~ Day 25 after conception This period is when the embryo is most susceptible to problems with development Most congenital malformation have their origins during this period 2nd Trimester: this is the period of growth and maturation of the organ systems During this trimester, the germ cells are migrating into the gonads Therefore, the female has the highest number of oocytes she will ever have at this time 3rd Trimester: this is the period of largest growth and weight gain in the fetus The fetus is putting on weight and preparing for birth Hair coat is put on the fetus Gestation Lengths (Averages) Swine 114 Days Sheep 148 Days Humans 266 Days (280 Days after last menstration) Cattle 280 Days Horses 340 Days http://www.ttuhsc.edu/som/obgyn/faculty/Prien/Lecture%20notes/ASFT2401LAB/ANSC%202401%20Lab%20Manual.htm (85 of 85) [6/10/2008 11:57:21 AM]