Chapter 40 Basic Principles of Animal Form Function
Chapter 40: Basic Principles of Animal Form & Function • AP Exam Payment Letter • Check your grades on the spreadsheets and report any discrepancies. • Are there any other exam questions? • This week we will begin our study of Human Anatomy & Physiology • Comparative anatomy among other animals will be covered as well.
Chapter 40: Basic Principles of Animal Form & Function Type of Evolution? Convergent evolution in fast swimmers (a) Tuna (b) Shark Homology or analogy? (c) Penguin Analogy – traits that each lineage evolved independently (d) Dolphin (e) Seal
Chapter 40: Basic Principles of Animal Form & Function 1. How has exchange with the environment evolved? - Simple diffusion from direct contact w/ environment - To internal exchange thru moist medium
Figure 40. 3 Contact with the environment Mouth Diffusion Gastrovascular cavity Diffusion (a) Single cell (b) Two cell layers
Figure 40. 4 Internal exchange surfaces of complex animals External environment Food CO 2 Mouth Respiratory system d oo Bl 0. 5 cm Cells Heart Nutrients Circulatory system 50 µm Animal body A microscopic view of the lung reveals that it is much more spongelike than balloonlike. This construction provides an expansive wet surface for gas exchange with the environment (SEM). 10 µm Interstitial fluid Digestive system Excretory system The lining of the small intestine, a digestive organ, is elaborated with fingerlike projections that expand the surface area for nutrient absorption (cross-section, SEM). Anus Unabsorbed matter (feces) Metabolic waste products (urine) Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM).
Chapter 40: Basic Principles of Animal Form & Function 2. Review…what is the hierarchy of biological organization? Atoms molecules organelles cells tissues organ systems…
What is a tissue & what are the 4 types? Group of cells in a matrix w/a common structure & function: – – Epithelial Connective Muscular Nervous
EPITHELIAL TISSUE Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often located where secretion or active absorption of substances is an important function. -Epithelial Tissue -Tightly packed sheets, cover the body, line organs & cavities w/in the body -Involved w/ secretion & absorption A stratified columnar epithelium A simple columnar epithelium A pseudostratified ciliated columnar epithelium Stratified squamous epitheli Cuboidal epithelia Simple squamous epithelia Basement membrane 40 µm
CONNECTIVE TISSUE 100 µm Chondrocytes Chondroitin sulfate Collagenous fiber Elastic fiber 100 µm -Connective Tissue -Binds & supports other tissues -3 types: -Collagenous -non-elastic – skin won’t rip -Elastic -elastin – skin reshapes -Reticular -Thin & branched -Made of collagen -Joins connective tissue to neighboring tissue Cartilage Loose connective tissue Adipose tissue Fibrous connective tissue Fat droplets 150 µm Nuclei 30 µm Blood Bone Central canal Red blood cells White blood cell Osteon 700 µm Plasma 55 µm
MUSCLE TISSUE 100 µm Skeletal muscle Muscle tissue (ch 49) -Long cells made of contractile proteins -Actin & myosin Multiple nuclei Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk Nucleus Smooth muscle 50 µm Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus 50 µm
Muscle tissue (ch 49) MUSCLE TISSUE 100 µm Skeletal muscle Multiple nuclei -3 kinds: 1. Skeletal – aka striated (w/ lines) 2. Cardiac – heart – branched cells 3. Smooth -no striations -In walls of digestive tract, bladder, arteries Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk Nucleus Smooth muscle 50 µm Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus 50 µm
MUSCLE TISSUE 100 µm Skeletal muscle Multiple nuclei Muscle fiber Sarcomere • Nervous tissue (ch 48) • Sense stimuli & transmits signals • neuron Cardiac muscle Nucleus Intercalated disk Nucleus Smooth muscle 50 µm Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus 50 µm
Chapter 40: Basic Principles of Animal Form & Function What is metabolism? - All of the chemical rxns within an organism - Catabolism – - breaks bonds – releases energy exergonic - Anabolism – - forms bonds – requires energy – endergonic
Figure 40. 7 Bioenergetics of an animal: an overview Organic molecules in food External environment Animal body Digestion and absorption Heat Nutrient molecules in body cells Carbon skeletons Cellular respiration Energy lost in feces Energy lost in urine Heat ATP Biosynthesis: growth, storage, and reproduction Heat Cellular work Heat
Chapter 40: Basic Principles of Animal Form & Function What is homeostasis? - Steady state, maintaining a constant condition of properties - regulating internal environment How is it achieved? - Negative feedback - the response is in the opposite direction of the stimulus - Positive feedback -response & stimulus are in the same direction
Figure 40. 11 A nonliving example of negative feedback: control of room temperature Response No heat produced How is set point maintained? Heater turned off Room temperature decreases Too hot Set point Too cold Set point Control center: thermostat Room temperature increases Heater turned on Response Heat produced
Chapter 40: Basic Principles of Animal Form & Function What are the 2 types of thermoregulation? - Ectothermic – heat & metabolism based on environment - Endothermic – heat & metabolism regulated internally
Figure 40. 12 The relationship between body temperature and environmental temperature in an aquatic endotherm and ectotherm 40 Body temperature (°C) River otter (endotherm) 30 20 Largemouth bass (ectotherm) 10 0 10 20 30 Ambient (environmental) temperature (°C) 40
How do organisms exchange heat with their environment? • Radiation • Emission of electromagnetic waves • Evaporation • Removal of heat from a surface of a liquid as gas molecules are released • Convection • Transfer of heat by the movement of air past a surface • Conduction • Transfer of heat from objects in direct contact
Figure 40. 13 Heat exchange between an organism and its environment Radiation is the emission of electromagnetic waves by all objects warmer than absolute zero. Radiation can transfer heat between objects that are not in direct contact, as when a lizard absorbs heat radiating from the sun. Convection is the transfer of heat by the movement of air or liquid past a surface, as when a breeze contributes to heat loss from a lizard’s dry skin, or blood moves heat from the body core to the extremities. Evaporation is the removal of heat from the surface of a liquid that is losing some of its molecules as gas. Evaporation of water from a lizard’s moist surfaces that are exposed to the environment has a strong cooling effect. Conduction is the direct transfer of thermal motion (heat) between molecules of objects in direct contact with each other, as when a lizard sits on a hot rock.
Chapter 40: Basic Principles of Animal Form & Function How can organisms exchange heat within their bodies? - Countercurrent heat exchange: - Arteries carrying warm blood/fluid down extremities - Passing veins carrying cool blood/fluid - Heat transfers from artery to vein
Figure 40. 15 Countercurrent heat exchangers 1 Arteries carrying warm blood down the legs of a goose or the flippers of a dolphin are in close contact with veins conveying cool blood in the opposite direction, back toward the trunk of the body. This arrangement facilitates heat transfer from arteries to veins (black arrows) along the entire length of the blood vessels. Canada goose Artery 1 35°C 30º 2 Near the end of the leg or flipper, where arterial blood has been cooled to far below the animal’s core temperature, the artery Vein can still transfer heat to the even colder 3 blood of an adjacent vein. The venous blood 33° continues to absorb heat as it passes warmer and warmer arterial blood traveling in the opposite direction. 27º 20º 18º 10º 9º 2 Pacific bottlenose dolphin 1 3 Blood flow 3 Vein Artery 2 3 As the venous blood approaches the center of the body, it is almost as warm as the body core, minimizing the heat lost as a result of supplying blood to body parts immersed in cold water. In the flippers of a dolphin, each artery is surrounded by several veins in a countercurrent arrangement, allowing efficient heat exchange between arterial and venous blood.
How do we achieve homeostasis for body temperature? 36 -38 o. C internal temp. Above set pt. – hypothalamus sweat glands & skin blood vessels dilate – result? Back to set pt. Fig. 40. 21 Human Thermoregulation Sweat glands secrete sweat that evaporates, cooling the body. Thermostat in hypothalamus activates cooling mechanisms. Increased body temperature (such as when exercising or in hot surroundings) Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Body temperature decreases; thermostat shuts off cooling mechanisms. Homeostasis: Internal body temperature of approximately 36– 38 C Body temperature increases; thermostat shuts off warming mechanisms. Decreased body temperature (such as when in cold surroundings) Blood vessels in skin constrict, diverting blood from skin to deeper tissues and reducing heat loss from skin surface. Skeletal muscles rapidly contract, causing shivering, which generates heat. Thermostat in hypothalamus activates warming mechanisms.
How do we achieve homeostasis for body temperature? 36 -38 o. C internal temp. Below set pt. – hypothalamus constrict blood vessels in skin & contract skeletal muscles (shivering) Result? Fig. 40. 21 Human Thermoregulation Sweat glands secrete sweat that evaporates, cooling the body. Thermostat in hypothalamus activates cooling mechanisms. Increased body temperature (such as when exercising or in hot surroundings) Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Body temperature decreases; thermostat shuts off cooling mechanisms. Homeostasis: Internal body temperature of approximately 36– 38 C Body temperature increases; thermostat shuts off warming mechanisms. Decreased body temperature (such as when in cold surroundings) Blood vessels in skin constrict, diverting blood from skin to deeper tissues and reducing heat loss from skin surface. Skeletal muscles rapidly contract, causing shivering, which generates heat. Thermostat in hypothalamus activates warming mechanisms.
Chapter 40: Basic Principles of Animal Form & Function How do animals thermoregulate in temperature extremes? - Torpor – physiological state in which activity is low & metabolism is decreased - Hibernation – winter – bears, Belding’s ground squirrels - Estivation – summer – many reptiles, bees
Figure 40. 22 Body temperature and metabolism during hibernation in Belding’s ground squirrels Additional metabolism that would be necessary to stay active in winter Temperature (°C) Metabolic rate (kcal per day) 200 100 Actual metabolism 0 35 30 25 Arousals Body temperature 20 15 10 5 0 -5 -10 -15 Outside temperature June August Burrow temperature October December February April
- Slides: 26
