Chapter 40

1. Chapter 40 Basic Principles of Animal Form and Function

2. Figure 40.1 Anatomy and Physiology • Comparative study of animals • form and function are closely correlated

3. Morphology • Physical laws and the environment constrain animal size and shape • Can place limits on the range of animal forms

4. Morphology • Evolutionary convergence • different species’ independent adaptation to an environmental challenge (a) Tuna (b) Shark (c) Penguin (d) Dolphin Figure 40.2a–e (e) Seal

5. Body size and shape affect interactions with the environment

6. Exchange with the Environment • Size and shape • directly effect how animal exchanges energy and materials with surroundings • Exchange involves dissolved substances crossing a membrane

7. Outside of cell Hydrophilic region TEM of a plasma membrane. The plasma membrane, here in a red blood cell, appears as a pair of dark bands separated by a light band. (a) Inside of cell 0.1 µm Hydrophobic region Hydrophilic region Phospholipid Proteins (b) Structure of the plasma membrane Plasma membrane • Functions as a selective barrier • Allows sufficient passage of nutrients and waste Carbohydrate side chain Figure 6.8 A, B

8. Diffusion (a) Single cell Single cell • protist living in water • Has surface area sufficient to accomodate its entire volume Figure 40.3a

9. Multicellular animal • with a sac body plan • body walls are only two cells thick, facilitating diffusion Mouth Gastrovascular cavity Diffusion Diffusion Figure 40.3b (b) Two cell layers

10. Complex organisms – highly folded internal surfaces External environment Food CO2 O2 Mouth Animal body Respiratory system Blood 50 µm 0.5 cm 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). Cells Heart Nutrients Circulatory system 10 µm Interstitial fluid Digestive system Excretory system The lining of the small intestine, a diges- tive organ, is elaborated with fingerlike projections that expand the surface area for nutrient absorption (cross-section, SEM). Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM). Anus Unabsorbed matter (feces) Metabolic waste products (urine) Figure 40.4

11. Animal form and function • Animals are composed of cells • Groups of cells with common structure and function make up tissues • Different tissues make up organs • Which together make up organ systems

12. Tissue Structure and Function • Different types of tissues • Have structures suited to their functions • Tissues classified into four main categories • Epithelial • Connective • Muscle • Nervous

13. Epithelial Tissue • Epithelial tissue • Covers the outside of the body and lines organs and cavities within the body • Contains cells that are closely joined

14. Epithelial tissue • Covers outside and lines inside of body Columnar epithelia, which have cells with relatively large cytoplasmic volumes, are often located where secretion or active absorption of substances is an important function. A simple columnar epithelium A stratified columnar epithelium A pseudostratified ciliated columnar epithelium • EPITHELIAL TISSUE • Cells closely joined • Act as barrier Stratified squamous epithelia Cuboidal epithelia Simple squamous epithelia Basement membrane Figure 40.5 40 µm

15. Connective Tissue • Connective tissue • Functions mainly to bind and support other tissues • Contains sparsely packed cells scattered throughout an extracellular matrix

16. Connective Tissue CONNECTIVE TISSUE • Binds and supports • Sparsely packed cells in an extra-cellular matrix 100 µm Chondrocytes Collagenous fiber Chondroitin sulfate Elastic fiber 100 µm Cartilage Loose connective tissue Adipose tissue Fibrous connective tissue Fat droplets Nuclei 150 µm 30 µm Blood Bone Central canal Red blood cells White blood cell Osteon Plasma Figure 40.5 700 µm 55 µm

17. Muscle Tissue • composed of long cells (muscle fibers) • contract in response to nerve signals • 3 types in vertebrate body: • skeletal • cardiac • smooth

18. Nervous Tissue • Senses stimuli and transmits signals throughout the animal

19. Muscle and nervous tissue MUSCLE TISSUE 100 µm Skeletal muscle Multiple nuclei Muscle fiber Sarcomere Cardiac muscle 50 µm Nucleus Intercalated disk Smooth muscle Nucleus Muscle fibers 25 µm NERVOUS TISSUE Process Neurons Cell body Nucleus Figure 40.5 50 µm

20. Lumen of stomach Mucosa. The mucosa is an epithelial layer that lines the lumen. Submucosa. The submucosa is a matrix of connective tissue that contains blood vessels and nerves. Muscularis. The muscularis consistsmainly of smooth muscle tissue. Serosa. External to the muscularis is the serosa,a thin layer of connective and epithelial tissue. 0.2 mm Organs • Organ tissues usually arranged in layers Figure 40.6

21. Organ systems • Based on major functions Table 40.1

22. Energy • Chemical energy in food sustains animal form and function • Used for growth, repair, physiology, reproduction • All organisms require chemical energy for • Growth, repair, physiological processes, regulation, and reproduction

23. Energy Sources and Allocation • Animals harvest chemical energy • From the food they eat • Bioenergetics is flow of energy thru an animal

24. Organic Compound Carbon Dioxide Oxygen Water Energy ATP and heat C6H12O6 O2 6CO2 6H20 G = -686 kcal/mol

25. Bioenergetics • Food used for energy or biosynthesis Organic molecules in food External environment Animal body Digestion and absorption Heat Energy lost in feces Nutrient molecules in body cells Energy lost in urine Cellular respiration Carbon skeletons Heat ATP Biosynthesis: growth, storage, and reproduction Cellular work Heat Figure 40.7 Heat

26. Quantifying Energy Use • An animal’s metabolic rate • The amount of energy an animal uses in a unit of time

27. (a) This photograph shows a ghost crab in arespirometer. Temperature is held constant in thechamber, with air of known O2 concentration flow-ing through. The crab’s metabolic rate is calculatedfrom the difference between the amount of O2entering and the amount of O2 leaving therespirometer. This crab is on a treadmill, runningat a constant speed as measurements are made. (b) Similarly, the metabolic rate of a manfitted with a breathing apparatus isbeing monitored while he works outon a stationary bike. Figure 40.8a, b Quantifying Energy Use • Can measure metabolic rate • determine amount of oxygen consumed or carbon dioxide produced by an organism

28. Measure energy value of intake and excretions …..

29. Measure heat production ….. One kilocalorie = heat necessary to raise 1L of H2O 1C Direct Calorimetry Measuring the heat as foods burn completely http://web.umr.edu/~gbert/bomb.gif

30. Does size matter?

31. Twice the radius Surface area of a sphere = 4πr2 So, if radius is 6 cm Surface area = 452.16 cm2 Surface area of a sphere = 4πr2 So, if radius is 12 cm Surface area= 1808.64 cm2 Volume of a sphere = 4/3πr3 So, if radius is 6 cm Volume = 904.32 cm3 Volume of a sphere = 4/3πr3 So, if radius is 12 cm Volume = 7234.56 cm3 Surface to volume ratio = .5 Surface to volume ratio = .25

32. Twice the radius Surface area of a sphere = 4πr2 So, if radius is 24 cm Surface area = 7234.56 cm2 Surface area of a sphere = 4πr2 So, if radius is 48 cm Surface area= 28938.24 cm2 Volume of a sphere = 4/3πr3 So, if radius is 24 cm Volume = 57876.48 cm3 Volume of a sphere = 4/3πr3 So, if radius is 48 cm Volume = 463011.84 cm3 Surface to volume ratio = .125 Surface to volume ratio = .063

33. What other factors affect metabolic rate? Activity Basal metabolic rate (BMR) – rate of a nongrowing endotherm that is at rest, has an empty stomach, and is not experiencing stress Human BMR Adult males 1600 – 1800 kcal/day Adult females 1300 – 1500 kcal/day Standard metabolic rate (SMR) – rate of a resting, fasting, nonstressed ectotherm at a particular temperature

34. Bioenergetic Strategies • Birds and mammals mainly endothermic, • warmed mostly by heat from metabolism • Typically higher metabolic rates • Amphibians and reptiles other than birds are ectothermic • gain heat mostly from external sources • lower metabolic rates

35. 500 A = 60-kg alligator A H 100 H A H = 60-kg human 50 H Maximum metabolic rate (kcal/min; log scale) 10 H H 5 A 1 A A 0.5 0.1 1 minute 1 second 1 hour 1 day 1 week Time interval Key Existing intracellular ATP ATP from glycolysis ATP from aerobic respiration Metabolic rate • In general, animal’s maximum possible metabolic rate • inversely related to the duration of the activity Figure 40.9

36. Endotherms Ectotherm Reproduction 800,000 Temperature regulation costs Basal metabolic rate Growth 340,000 Activity costs Annual energy expenditure (kcal/yr) 8,000 4,000 0.025-kg female deer mouse from temperate North America 4-kg male Adélie penguin from Antarctica (brooding) 60-kg female human from temperate climate 4-kg female python from Australia (a) Total annual energy expenditures 438 Human 233 Energy expenditure per unit mass (kcal/kg•day) Python Deer mouse Adélie penguin 36.5 5.5 Energy expenditures per unit mass (kcal/kg•day) (b) Energy Budgets • An animal’s use of energy • Is partitioned to BMR (or SMR), activity, homeostasis, growth, and reproduction Figure 40.10a, b

37. Homeostasis • Animals regulate their internal environment within relatively narrow limits • Homeostasis is a balance between external changes and internal control mechanisms

38. Regulating and Conforming • Regulating and conforming • Are two extremes in how animals cope with environmental fluctuations

39. Regulating and Conforming • regulator • uses internal controls to moderate internal change in the face of external, environmental fluctuation • conformer • allows its internal condition to vary with certain external changes

40. Response No heat produced Heater turned off Room temperature decreases Set point Too hot Set point Too cold Set point Control center: thermostat Room temperature increases Heater turned on Response Heat produced Homeostasis • A homeostatic control system has three functional components • A receptor, a control center, and an effector Figure 40.11

41. Homeostasis • Most homeostatic control systems function by negative feedback • buildup of the end product of the system shuts the system off • or positive feedback • a change in some variable triggers mechanisms that amplify the change • Eg. childbirth

42. Thermoregulation • involves anatomy, physiology, and behavior • Thermoregulation • Is the process by which animals maintain an internal temperature within a tolerable range

43. 40 River otter (endotherm) 30 Body temperature (°C) 20 Largemouth bass (ectotherm) 10 0 10 20 30 40 Ambient (environmental) temperature (°C) Ectotherms vs endotherms • Ectotherms generally tolerate greater variation in internal temperature than endotherms Figure 40.12

44. Cost • Endothermy more energetically expensive than ectothermy • But buffers animals’ internal temperatures • enables animals to maintain a high level of aerobic metabolism

45. 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. 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. 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. Modes of Heat Exchange • Organisms exchange heat by four physical processes Figure 40.13

46. Insulation • Insulation, major thermoregulatory adaptation in mammals and birds • Reduces flow of heat between animal and environment • Includes feathers, fur, or blubber

47. Integumentary system • In mammals, acts as insulating material Hair Epidermis Sweat pore Muscle Dermis Nerve Sweat gland Hypodermis Adipose tissue Blood vessels Oil gland Figure 40.14 Hair follicle

48. Circulatory Adaptations • Many endotherms and some ectotherms • Can alter the amount of blood flowing between the body core and the skin

49. Circulatory Adaptations • In vasodilation • Blood flow in the skin increases, facilitating heat loss • In vasoconstriction • Blood flow in the skin decreases, lowering heat loss

50. Pacific bottlenose dolphin 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. 1 Canada goose Blood flow 1 Artery Vein Vein Near the end of the leg or flipper, where arterial blood has been cooled to far below the animal’s core temperature, the artery can still transfer heat to the even colder blood of an adjacent vein. The venous blood continues to absorb heat as it passes warmer and warmer arterial blood traveling in the opposite direction. 2 Artery 3 35°C 33° 3 30º 27º 20º 18º 2 10º 9º 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. 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. 2 3 Countercurrent heat exchange • Many marine mammals and birds • Have arrangements of blood vessels, countercurrent heat exchangers • reduce heat loss 3 1 Figure 40.15