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Chapter 42 Lecture and Animation Outline To run the animations you must be in Slideshow View. Use the buttons on the animation to play, pause, and turn audio/text on or off. Please Note: Once you have used any of the animation functions (such as Play or Pause), you must first click on the slide’s background before you can advance to the next slide. See separate PowerPoint slides for all figures and tables pre-inserted into PowerPoint without notes and animations. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. The Animal Body and Principles of Regulation Chapter 42 Organization of Vertebrate Body • There are four levels of organization 1. 2. 3. 4. Cells Tissues Organs Organ systems • Bodies of vertebrates are composed of different cell types – Humans have 210 3 Organization of Vertebrate Body • Tissues – Groups of cells that are similar in structure and function – 3 fundamental embryonic tissues are called germ layers • Endoderm, mesoderm, and ectoderm – In adult vertebrates, there are four primary tissues • Epithelial, connective, muscle, and nerve 4 Organization of Vertebrate Body • Organs – Combinations of different tissues that form a structural and functional unit • Organ systems – Groups of organs that cooperate to perform the major activities of the body – Vertebrate body contains 11 principal organ systems 5 Organization of Vertebrate Body Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell Tissue Organ Organ System Cardiac Muscle Cell Cardiac Muscle Heart Circulatory System 6 Organization of Vertebrate Body • General body plan of all vertebrates is essentially a tube within a tube – Inner tube – digestive tract – Outer tube – main vertebrate body • Supported by a skeleton – Outermost layer – skin and its accessories 7 Organization of Vertebrate Body • 2 main body cavities – Dorsal body cavity • Forms within skull and vertebrae – Ventral body cavity • Bounded by the rib cage and vertebral column • Divided by the diaphragm into – Thoracic cavity – heart and lungs » Pericardial cavity: Around the heart » Pleural cavity: Around the lungs – Abdominopelvic cavity – most organs » Peritoneal cavity – coelomic space 8 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Section 1 Cranial cavity Vertebrae Section 3 Section 2 Brain Vertebral cavity Spinal cord Dorsal body cavity Right pleural cavity Pericardial cavity Thoracic cavity Diaphragm Ventral body cavity Peritoneal cavity a. All vertebrates have dorsal and ventral body cavities 9 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Section 1 Cranial cavity Section 3 Section 2 Brain Muscles Mandible Pharynx Muscles Rib Vertebral cavity Pleural cavity Epiglottis Lungs Sternum Muscles Vertebra Esophagus Trachea Anterior vena cava Thoracic cavity Spleen Spinal cord Kidney Cecum Colon Small intestines Abdominal cavity b. Cross sections through three body regions 10 Epithelial Tissue • An epithelial membrane, or epithelium, covers every surface of the vertebrate body • Can come from any of the 3 germ layers • Some epithelia change into glands • Cells of epithelia are tightly bound together – Provide a protective barrier 11 Epithelial Tissue • Epithelia possess remarkable regenerative powers replacing cells throughout life • Epithelial tissues attach to underlying connective tissues by a fibrous membrane – Basal surface – secured side – Apical surface – free side – Inherent polarity important for their function 12 Epithelial Tissue • Two general classes – Simple – one layer thick – Stratified – several layers thick • Each class subdivided into – Squamous cells – flat – Cuboidal cells – about as wide as tall – Columnar cells – taller than they are wide 13 Simple Epithelium • Simple squamous epithelium – Lines lungs and blood capillaries – Delicate nature permits diffusion • Simple cuboidal epithelium – Lines kidney tubules and several glands • Simple columnar epithelium – Lines airways of respiratory tract and most of the gastrointestinal tract – Contains goblet cells – secrete mucus 14 15 Simple Epithelium • Glands of vertebrates form from invaginated epithelia • Exocrine glands – Connected to epithelium by a duct – Sweat, sebaceous, and salivary glands • Endocrine glands – Ductless – lost duct during development – Secretions (hormones) enter blood 16 Stratified Epithelium • 2 to several layers thick • Named according to the features of their apical cell layers • Epidermis is a stratified squamous epithelium – Terrestrial vertebrates have a keratinized epithelium • Contains water-resistant keratin – Lips are covered with nonkeratinized, stratified squamous epithelium 17 18 Connective Tissues • Derive from embryonic mesoderm • Divided into two major classes – Connective tissue proper • Loose or dense – Special connective tissue • Cartilage, bone, and blood • All have abundant extracellular material called the matrix – Protein fibers plus ground substance 19 Connective Tissue Proper • Fibroblasts produce and secrete extracellular matrix • Loose connective tissue – Cells scattered within a matrix that contains a large amount of ground substance – Strengthened by protein fibers • Collagen – supports tissue • Elastin – makes tissue elastic • Reticulin – helps support the network of collagen 20 Connective Tissue Proper • Adipose cells (fat cells) also occur in loose connective tissue – Develop in large groups in certain areas, forming adipose tissue Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 200 µm © Biophoto Associates/ Photo Researchers, Inc. 21 Connective Tissue Proper • Dense connective tissue – Contains less ground substance than loose connective tissue – Dense regular connective tissue • Collagen fibers line up in parallel • Makes up tendons and ligaments – Dense irregular connective tissue • Collagen fibers have different orientations • Covers kidney, muscles, nerves, and bone 22 23 Special Connective Tissue • Cartilage – Ground substance made from characteristic glycoprotein (chondroitin) and collagen fibers in long, parallel arrays – Firm and flexible tissue that does not stretch – Great tensile strength – Found in joint surfaces and other locations – Chondrocytes (cartilage cells) live within lacunae (spaces) in the ground substance 24 Special Connective Tissue • Bone – Osteocytes (bone cells) remain alive in a matrix hardened with calcium phosphate – Communicate through canaliculi • Blood – Extracellular material is the fluid plasma – Erythrocytes – red blood cells – Leukocytes – white blood cells – Thrombocytes – platelets 25 26 Muscle Tissue • Muscles are the motors of vertebrate bodies • Three kinds: smooth, skeletal, and cardiac – Skeletal and cardiac muscles are also known as striated muscles – Skeletal muscle is under voluntary control, whereas contraction of the other two is involuntary 27 Muscle Tissue • Smooth muscle – Found in walls of blood vessels and visceral organs – Contain a single nucleus • Skeletal muscle – Usually attached to bone by tendons, so muscle contraction causes bones to move – Muscle fibers (cells) are multinucleated – Contract by means of myofibrils, which contain ordered actin and myosin filaments 28 Muscle Tissue • Cardiac muscle – Composed of smaller, interconnected cells – Each with a single nucleus – Interconnections appear as dark lines called intercalated disks • Gap junctions link adjacent cells – Enable cardiac muscle cells to form a single functioning unit 29 30 Heartbeat intrinsic to the heart Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Isolated heart Heart placed in solution with nutrients and oxygen. Heart continues to contract with no connection to the nervous system. 31 Nerve Tissue • Cells include neurons and their supporting cells (neuroglia) • Most neurons consist of three parts – Cell body – contains the nucleus – Dendrites – highly branched extensions • Conduct electrical impulses toward the cell body – Axon – single cytoplasmic extension • Conducts impulses away from cell body 32 Nerve Tissue • Neuroglia – Do not conduct electrical impulses – Support and insulate neurons and eliminate foreign materials in and around neurons – Associate with axon to form an insulating cover called the myelin sheath • Gaps (nodes of Ranvier) are involved in acceleration of impulses 33 Nerve Tissue • Nervous system is divided into – Central nervous system (CNS) • Brain and spinal cord • Integration and interpretation of input – Peripheral nervous system (PNS) • Nerves and ganglia (collections of cell bodies) • Communication of signal to and from the CNS to the rest of the body 34 35 Overview of Organ Systems • Communication and integration – Three organ systems detect external stimuli and coordinate the body’s responses – Nervous, sensory, and endocrine systems • Support and movement – Musculoskeletal system consists of two interrelated organ systems 36 Overview of Organ Systems • Regulation and maintenance – Four organ systems regulate and maintain the body’s chemistry – Digestive, circulatory, respiratory, and urinary systems • Defense – The body defends itself – Integumentary and immune systems 37 Overview of Organ Systems • Reproduction and development – The biological continuity of vertebrates – In females, the system also nurtures the developing embryo and fetus 38 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nervous System Endocrine System Brain Hypothalamus Pituitary Skeletal System Skull Thyroid Thymus Spinal cord Adrenal gland Pancreas Sternum Pelvis Testis (male) Nerves Femur Ovary (female) 39 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Muscular System Digestive System Circulatory System Salivary glands Pectoralis major Esophagus Biceps Liver Rectus abdominus Stomach Small intestine Large intestine Heart Veins Arteries Sartorius Quadriceps Gastrocnemius 40 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lymphatic/Immune System Reproductive System (male) Reproductive System (female) Lymph nodes Thymus Spleen Bone marrow Vas deferens Penis Testis Fallopian tube Ovary Uterus Vagina Lymphatic vessels 41 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lymphatic/Immune System Reproductive System (male) Reproductive System (female) Lymph nodes Thymus Spleen Bone marrow Vas deferens Penis Testis Fallopian tube Ovary Uterus Vagina Lymphatic vessels 42 Homeostasis • As animals have evolved, specialization of body structures has increased • For cells to function efficiently and interact properly, internal body conditions must be relatively constant • The dynamic constancy of the internal environment is called homeostasis • It is essential for life 43 Homeostasis • Negative feedback mechanisms – Changing conditions are detected by sensors (cells or membrane receptors) – Information is fed to an integrating center, also called comparator (brain, spinal cord, or endocrine gland) – Compares conditions to a set point – If conditions deviate too far from a set point, biochemical reactions are initiated to change conditions back toward the set point 44 Homeostasis • Humans have set points for body temperature, blood glucose concentrations, electrolyte (ion) concentration, tendon tension, etc. • Integrating center is often a particular region of the brain or spinal cord • Effectors (muscles or glands) change the value of the condition in question back toward the set point value 45 Homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Response Move system towards set point Effector Causes changes to compensate for deviation Negative feedback (–) Stimulus Deviation from set point Sensor Integrating Center Constantly monitors conditions Compares conditions to a set point based on a desired value 46 Homeostasis • Mammals and birds are endothermic – Maintain a relatively constant body temperature independent of the environmental temperature – Humans 37oC or 98.6oF – Changes in body temperature are detected by the hypothalamus in the brain 47 Homeostasis • Negative feedback mechanisms often oppose each other to produce finer degree of control • Many internal factors are controlled by antagonistic effectors • Have “push–pull” action • Increasing activity of one effector is accompanied by decrease in the other 48 Homeostasis • Antagonistic effectors are involved in the control of body temperature • If hypothalamus detects high temperature – Promotes heat dissipation via sweating and dilation of blood vessels in skin • If hypothalamus detects low temperature – Promotes heat conservation via shivering and constriction of blood vessels in skin 49 Homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Negative feedback Stimulus Stimulus Room temperature changes from set point Body temperature deviates from set point (–) (–) Negative feedback Negative feedback Sensor Response Room warms, temperature increases toward set point Effector If Below Set Point • AC turns off • Furnace turns on a. Thermometer in wall unit detects the change in temperature (–) (–) Sensor Response Response Room cools, temperature decreases toward set point Body temperature rises Neurons in hypothalamus detect the change in temperature Integrating Center Integrating Center Set Point = 70F Set Point = 37C Thermostat compares temperature with set point Negative feedback Effector Effector If Above Set Point If Below Set Point • AC turns on • Furnace turns off • Blood vessels to skin contract • Muscles contract, shiver Neurons in hypothalamus compare input from sensory neurons with set point Response Body temperature drops Effector If Above Set Point • Blood vessels to skin dilate • Glands release sweat b. 50 Homeostasis • Positive feedback mechanisms – Enhance a change – not common – These do not in themselves maintain homeostasis – Important components of some physiological mechanisms • Blood clotting • Contraction of uterus during childbirth 51 Homeostasis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stimulus Fetus is pushed against the uterine opening Sensor Receptors in the inferior uterus detect increased stretch Integrating Center The brain receives stretch information from the uterus, and compares it with the set point (+) Positive feedback loop completed— results in increased force against inferior uterus (cervix), promoting the birth of the baby Response Oxytocin causes increased uterine contractions Effector If Above Set Point The pituitary gland is stimulated to increase secretion of the hormone oxytocin 52 Please note that due to differing operating systems, some animations will not appear until the presentation is viewed in Presentation Mode (Slide Show view). You may see blank slides in the “Normal” or “Slide Sorter” views. All animations will appear after viewing in Presentation Mode and playing each animation. Most animations will require the latest version of the Flash Player, which is available at http://get.adobe.com/flashplayer. 53 Regulating Body Temperature • Temperature is one of the most important aspects of the environment • Some organisms have a body temperature that conforms to the environment • Other organisms regulate their body temperature 54 • Q10 is a measure of temperature sensitivity – The rate of any chemical reaction is affected by temperature – The rate increases with increasing temperature – Every 10°C increase in temperature doubles the reaction rate 55 • Temperature determined by internal and external factors – Overall metabolic rate and body temperature are interrelated – Organisms must deal with external and internal factors that relate body heat, metabolism, and the environment body heat = heat produced + heat transferred 56 Mechanisms of heat transfer • Radiation. The transfer of heat by electromagnetic radiation • Conduction. The direct transfer of heat between two objects. Energy is transferred from hotter objects to colder ones. • Convection. Convection is the transfer of heat brought about by the movement of a gas or liquid. • Evaporation. Heat of vaporization or the amount of energy needed to change them from a liquid to a gas phase 57 • Ectotherms regulate temperature using behavior – Low metabolic rates – Regulate their temperature using behavior Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Preflight No wing movement Warm up Shiver-like contraction of thorax muscles Temperature (ºC) of thorax muscles 40 Flight Full-range movement of wings 35 30 25 –1 0 1 Time (min) 2 3 4 58 • Endotherms create internal metabolic heat – Conservation or dissipation – Heat transfer is controlled by amount of blood flow to the surface of the animal • Countercurrent exchange – Allows sustained high-energy activity – Tradeoff is the high metabolic rate 59 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Core body temperature 36°C 5°C Temperature of environment Warm blood Cold blood Cold blood Capillary bed Veins Artery Countercurrent heat exchange 60 • Body size and insulation – Changes in body mass have a large effect on metabolic rate – Smaller animals consume much more energy per unit – body mass than larger animals – Summarized in the “mouse to elephant” curve • Nonproportionality of metabolic rate versus size of mammals 61 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 8 7 Shrew Mass-specific metabolic rate (mL O2 × g–1 × h–1) 6 5 4 3 Harvest mouse 2 1 Kangaroo mouse Cactus mouse Mouse Flying squirrel Cat Rat Dog Sheep Rabbit 0 0.01 0.1 1 10 Human Horse Elephant 100 1000 log Mass (kg) Relationship between body mass and metabolic rate in mammals 62 • Mammalian thermoregulation is controlled by the hypothalamus – Neurons in the hypothalamus detect the temperature change – Stimulation of the heat-losing center • Peripheral blood vessel dilation • Sweating – Stimulation of heat-promoting center • • • • Thermogenesis Constriction of blood peripheral blood vessels Epinephrine production by adrenal glands Anterior pituitary produces TSH 63 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Perturbing factor Response Negative feedback Sun Body temperature falls Effector Stimulus Body temperature rises Stimulus Body temperature drops ( Sensor Integrating Center Thermoreceptors Hypothalamus ( • Blood vessels dilate • Glands release sweat ) Effector • Blood vessels constrict • Skeletal muscles contract, shiver ) Perturbing factor Snow and ice Response Negative feedback Body temperature rises Control of body temperature by the hypothalamus 64