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Transcript
Chapter 4 Body Basics Body Chemistry Concepts Matter: comprised of an atom that contains protons and electrons Protons: + charged particles in the nucleus of the atom Electrons: - charged particles that surround the nucleus of an atom Number of electrons equals the number of protons, atoms are neutral Elements: each type of atom; under ordinary conditions, a substance that cannot be broken down into distinctive components ◦ Building blocks of matter Minerals: elements that are found in the earth’s crust Essential nutrients Ca, Fe, K Essential Elements Molecules Molecule: matter that forms when two or more atoms interact and are held together by a chemical bond Chemical bond: attraction that holds atoms together Definitions…. Compounds: molecules that contain two or more different elements Solution: evenly distributed mixture of two compounds Solvent: primary compound of a solution Solute: lesser component in a solution Solubility: describes how easily a substance dissolves in liquid solvent More definitions…. Ion: atom or group of atoms that has a positive or negative charge H+: hydrogen ion chemical formula Electrolytes: ions that conduct electricity when they are dissolved in a solution Acids: substances that donate hydrogen ions Bases: substances that accept hydrogen ions pH: measure of the acidity or alkalinity of a solution And more definitions…. Chemical reactions: process that changes that atomic arrangement of molecules Digestion: process by which large ingested molecules are mechanically and chemically broken down Salt: substance when acid combines with a base Metabolism: the sum of all chemical reactions occurring in living cells Basic Physiology Concepts Anatomy: the scientific study of cells and other body structures Physiology: scientific study of the functioning of cells and other body structures Human Cell Human Cell Organelles: structures in cells that perform specialized functions Nucleus: Organization and expression of the genetic material (DNA) Plasma membrane: Movement of substances into and out of the cell Ribosome: protein synthesis Mitochondrion: Site of ATP (high-energy molecule) synthesis Cells cont… Tissues: collection of cells that perform a specific function Epithelial tissues: cells that line every body surface (skin, inside of blood vessels) Connective tissues: type of cells that hold together, protect and support organs (fat, bone and blood) Organization of the human body Cell Organ Tissue System Definitions Organ: collection of tissues that perform a specific function Organ system: Collection of organs that work together to perform a major function Homeostasis: relatively constant internal environment in the body that is critical for good health and survival Definitions… Arteries: vessels that carry blood away from the heart Capillaries: smallest blood vessels Veins: vessels that return blood to the heart. Cardiovascular System •Heart •Blood vessels •Blood •Circulation of blood throughout the body Respiratory System Exchange of O2 and CO2 Blood transports the respiratory gases, with hemoglobin carrying the oxygen The heart pumps oxygen-poor blood to the lungs –In the lungs it picks up O2and drops off CO2 –In the tissues, cells pick up CO2and drop off O2 –Gases diffuse down pressure gradients in the lungs and the tissues Gas exchange in the body Hemoglobin is a protein in red blood cells –It carries most of the oxygen in the blood Heme group Iron atom O2 loaded in lungs O2 unloaded in tissues Polypeptide chain O2 O2 Hemoglobin helps buffer the pH of blood and carries some CO2 Most CO2 in the blood combines with water to form carbonic acid ◦ –The carbonic acid breaks down to form H+ions and bicarbonate ions ◦ –These help buffer the blood Most CO2 is transported to the lungs in the form of bicarbonate ions Lymphatic System Defense and immunity against infectious agents, fluid balance, WBC production, absorption of fat-soluble nutrients from intestinal track Other parts: ◦ Lymphatic fluid ◦ WBC ◦ Primary lymphoid organs Bone marrow and thymus ◦ Secondary lymphoid organs Spleen, lymph nodes Lymphatic System Lymphoid Cells Lymphocytes are the main cells involved in the immune response ◦ Two main varieties: T cells B cells T cells and B cells protect the body against antigens ◦ Antigen – substances that can stimulate the immune system Self Nonself Bacteria and their toxins; viruses Mismatched RBCs or cancer cells Lymphocytes T cells ◦ Manage the immune response ◦ Attack and destroy foreign cells B cells ◦ Produce plasma cells, which secrete antibodies ◦ Antibodies immobilize antigens Other Lymphoid Cells Macrophages – phagocytize foreign substances and help activate T cells Dendritic cells – spiny-looking cells with functions similar to macrophages Reticular cells – fibroblast–like cells that produce a stroma, or network, that supports other cell types in lymphoid organs Thymus The thymus differs from other lymphoid organs in important ways ◦ It functions strictly in T lymphocyte maturation ◦ It does not directly fight antigens ◦ The stroma of the thymus consists of starshaped epithelial cells (not reticular fibers) ◦ These epithelial cells (thymocytes) secrete the hormones that stimulate lymphocytes to become immunocompetent Thymus Spleen Largest lymphoid organ, located on the left side of the abdominal cavity beneath the diaphragm It is served by the splenic artery and vein, which enter and exit at the hilus Functions: ◦ Site of lymphocyte proliferation ◦ Immune surveillance and response ◦ Cleanses the blood Additional Spleen Functions Stores breakdown products of RBCs for later reuse Spleen macrophages salvage and store iron for later use by bone marrow Site of fetal erythrocyte production (normally ceases after birth) Stores blood platelets Spleen Lymphoid Tissue Diffuse lymphatic tissue – scattered reticular tissue elements in every body organ ◦ Larger collections appear in the lamina propria of mucous membranes and lymphoid organs Lymphatic follicles (nodules) – solid, spherical bodies consisting of tightly packed reticular elements and cells ◦ Germinal center composed of dendritic and B cells ◦ Found in isolation and as part of larger lymphoid organs Tonsils Simplest lymphoid organs; form a ring of lymphatic tissue around the pharynx Location: Palatine tonsils – either side of the posterior end of the oral cavity Lingual tonsils – lie at the base of the tongue Pharyngeal tonsil – posterior wall of the nasopharynx Tubal tonsils – surround the openings of the auditory tubes into the pharynx Urinary System Elimination of salts, water, and wastes; maintenance of fluid balance Muscular System Movement and stability of body Facts about muscles Muscle: A tissue composed of fibers capable of contracting to effect bodily movement There are about 650 muscles in the human body. Every person has a unique tongue print. Hiccups are spasm of the diaphragm. Types of Muscles Skeletal muscles: Attached to bones. (what happens when you extend your arm?) Smooth muscle: Surround organs, tubes, eg. stomach, urinary bladder, blood vessels. Contract propels content through organs (eg. expel urine). Cardiac muscles: Heart muscle makes your heart pump blood. Skeletal System Facts about skeletal system Do we have more bones when we are a baby or when we are all grown up? Baby has 305 bones and an adult has 206 bones. This is because as we grown some of our bones join together to form one bone. The longest bone in our bodies is the femur (thigh bone). The smallest bone is the stirrup bone inside the ear. Each hand has 26 bones in it. our nose and ears are not made of bone; they are made of cartilage, a flexible substance that is not as hard as bone. Differences between males and females: Males and females have slightly different skeletons, including a different elbow angle. Males have slightly thicker and longer legs and arms; females have a wider pelvis and a larger space within the pelvis, through which babies travel when they are born. Five main functions of the human skeleton Protect the vital organs we talked about last week 2. Give us shape 3. Allow us to move because our muscles are attached to our bones 4. Storage of nutrients such as calcium and silicon 5. Formation of blood cells Nervous System Thought process, regulation and coordination of many body activities, detection of changes in external and internal environments Basic nerve structure 3 types of nerve structures sensory neurone relay neurone motor neurone Endocrine System Main Function: It releases hormones into the blood to signal other cells to behave in certain ways. It is a slow but widespread form of communication. Regulation and coordination of many body activities, including growth, nutrient balance, and reproduction Endocrine System (Pituitary Gland) Function: It secretes nine hormones that directly regulate many body functions and controls functions of other glands. Disorders: Too much growth hormones (GH) in early childhood can result in a condition called gigantism. Too little GH can result in Pituitary Dwarfism. Endocrine (thyroid gland) Function: plays a major role in regulation the body’s metabolism. Disorders: If the Thyroid Gland produces too much Thyroxin, it can cause a condition known as Hyperthyroidism. If too little thyroxin produces it is called Hypothyroidism. Endocrine (pancreas) Function: The Insulin and Glycogen in the Pancreas help to keep the level of glucose in the blood stable. Disorders: When the Pancreas fails to produce or properly use Insulin, it can cause a condition known as Diabetes Mellitus. Endocrine (Adrenal Gland) Functions: -The adrenal glands release Adrenaline in the body that helps prepare for and deal with stress. -Also regulates kidney function. Endocrine (ovaries) Functions: ◦ Pair of reproductive organs found in women that produce eggs. ◦ Also secrete estrogen and progesterone, which control ovulation and menstruation. Endocrine (testes) Functions: ◦ Pair of reproductive glands that produces sperm. ◦ Also secrete Testosterone to give the body its masculine characteristics. Integumentary System Functions of skin Protection Cushions and insulates and is waterproof Protects from chemicals, heat, cold, bacteria Screens UV Synthesizes vitamin D with UV Regulates body heat Prevents unnecessary water loss Sensory reception (nerve endings) Dermis Strong, flexible connective tissue: your “hide” Cells: fibroblasts, macrophages, mast cells, WBCs Fiber types: collagen, elastic, reticular Rich supply of nerves and vessels Critical role in temperature regulation (the vessels) Two layers ◦ Papillary – areolar connective tissue; includes dermal papillae ◦ Reticular – “reticulum” (network) of collagen and reticular fibers Burns First-degree (epidermis only; redness) Second-degree (epidermis and dermis, with blistering) Third-degree (full thickness, destroying epidermis, dermis, often part of hypodermis) Skin Cancer Nails Hair Functions of hair ◦ Warmth – less in man than other mammals ◦ Sense light touch of the skin ◦ Protection - scalp Parts ◦ Root imbedded in skin ◦ Shaft projecting above skin surface Make up of hair – hard keratin Hair cont… Types of hair ◦ Vellus: fine, short hairs ◦ Intermediate hairs ◦ Terminal: longer, courser hair Hair color ◦ Amount of melanin for black or brown; distinct form of melanin for red ◦ White: decreased melanin and air bubbles in the medulla ◦ Genetically determined though influenced by hormones and environment Reproductive System Procreation Reproduction Primary sex organs (gonads) – testes in males, ovaries in females ◦ Gonads produce sex cells called gametes and secrete sex hormones Accessory reproductive organs – ducts, glands, and external genitalia Sex hormones – androgens (males), and estrogens and progesterone (females) Digestive System Digestion and absorption of nutrients Digestion Phases and structures Phases ◦ Ingestion ◦ Movement ◦ Digestion ◦ Absorption ◦ Further digestion Structures •Mouth •Oral Cavity •Pharynx •Esophagus •Stomach •Duedenum •Jejenum •IIleum •Cecum •Ascending colon •Transverse colon Mouth Mechanical digestion Senses taste and texture Salivary glands Esophagus A tube that extends about 10 inches from the back of the mouth, the pharynx, to the top of the stomach Epiglottis: flap of tissue that folds down over the windpipe to keep food from entering the respiratory system Gastroesophageal sphincter: section of esophagus next to stomach that controls the opening to the stomach Stomach Holds up to four cups of food Chyme: mixture of gastric juices and partially digested food Pyloric sphincter: controls the rate in which chyme is released into the small intestine Stomach usually empties in about 4 hours Stomach cont… Functions ◦ Mix food ◦ Reservoir ◦ Start digestion of Protein Nucleic acids Fats ◦ Activates some enzymes ◦ Destroy some bacteria ◦ Makes intrinsic factor – B 12 absorption ◦ Destroys some bacteria ◦ Absorbs Alcohol Water Lipophilic acid B 12 Small intestine 6 1/2 feet long Villa 3 sections ◦ Duodenum ◦ Jejunum ◦ Ileum Villi in small intestine Small intestine cont… Secretes digestive enzymes ◦ Peptidases Amino Di Tri◦ Sucrases ◦ Maltase ◦ Lactase ◦ Saccharidases Di Tri◦ Lipase ◦ Nucleases •Requires pancreatic enzymes & bile to complete digestion Large intestine Regions ◦ Cecum – Appendix ◦ Colon Ascending Transverse Descending ◦ Rectum ◦ Anal canal Chyme becomes feces Feces Formation Chyme dehydrated to form feces Feces composition ◦ ◦ ◦ ◦ ◦ Water Inorganic salts Epithelial cells Bacteria Byproducts of digestion Defecation ◦ Peristalsis pushes feces into rectum ◦ Rectal walls stretch Accessory Organs Play role in digestion even though chyme does not move through them Liver: ◦ process and stores nutrients ◦ Makes cholesterol ◦ Uses lipids to make bile Gallbladder ◦ When food and fat are in the duodenum, the small intestine send signal for gallbladder to release bile into duodenum Pancreas ◦ Produces and secretes most of the enzymes that break down carbs, protein, and fat in GI tract ◦ Secretes biocarbonate ions that neutralizes HCL in chyme Liver cont… Liver: Functions ◦ Makes bile Detergent – emulsifies fats Release promoted by: Vagus n. CCK Secretin Contains Water Bile salts Bile pigments Electrolytes Cholesterol Lecithin More Liver…yuck ◦ Detoxifies/removes Drugs Alcohol ◦ Stores ◦ ◦ ◦ ◦ Gycolgen Vitamins (A, D, E, K) Fe and other minerals Cholesterol Activates vitamin D Fetal RBC production Phagocytosis Metabolizes absorbed food molecules Carbohydrates Proteins Lipids Dual blood supply ◦ Hepatic portal vein Direct input from small intestine ◦ Hepatic artery/vein Direct links to heart