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Chapter 40 Basic Principles of Animal Form and Function

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[object Object],[object Object],Figure 40.1

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Physical Laws and Animal Form ,[object Object],[object Object]

[object Object],[object Object],Figure 40.2a–e (a) Tuna (b) Shark (c) Penguin (d) Dolphin (e) Seal

Exchange with the Environment ,[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],Figure 40.3a Diffusion (a) Single cell

[object Object],[object Object],Figure 40.3b Mouth Gastrovascular cavity Diffusion Diffusion (b) Two cell layers

External environment Food CO 2 O 2 Mouth Animal body Respiratory system Circulatory system Nutrients Excretory system Digestive system Heart Blood Cells Interstitial fluid Anus Unabsorbed matter (feces) Metabolic waste products (urine) 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). 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). Inside a kidney is a mass of microscopic tubules that exhange chemicals with blood flowing through a web of tiny vessels called capillaries (SEM). 0.5 cm 10 µm 50 µm Figure 40.4

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[object Object],[object Object],[object Object],[object Object],Tissue Structure and Function

Epithelial Tissue ,[object Object],[object Object],[object Object]

[object Object],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. A stratified columnar epithelium A simple columnar epithelium A pseudostratified ciliated columnar epithelium Stratified squamous epithelia Simple squamous epithelia Cuboidal epithelia Basement membrane 40 µm Figure 40.5

Connective Tissue ,[object Object],[object Object],[object Object]

[object Object],Collagenous fiber Elastic fiber Chondrocytes Chondroitin sulfate Loose connective tissue Fibrous connective tissue 100 µm 100 µm Nuclei 30 µm Bone Blood Central canal Osteon 700 µm 55 µm Red blood cells White blood cell Plasma Cartilage Adipose tissue Fat droplets 150 µm CONNECTIVE TISSUE Figure 40.5

Muscle Tissue ,[object Object],[object Object],[object Object]

Nervous Tissue ,[object Object],[object Object]

[object Object],MUSCLE TISSUE Skeletal muscle 100 µm Multiple nuclei Muscle fiber Sarcomere Cardiac muscle Nucleus Intercalated disk 50 µm Smooth muscle Nucleus Muscle fibers 25 µm NERVOUS TISSUE Neurons Process Cell body Nucleus 50 µm Figure 40.5

Organs and Organ Systems ,[object Object],[object Object]

[object Object],[object Object],Figure 40.6 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 consists mainly of smooth muscle tissue. 0.2 mm Serosa. External to the muscularis is the serosa, a thin layer of connective and epithelial tissue.

[object Object],[object Object],[object Object],[object Object],[object Object],Bioenergetics

Energy Sources and Allocation ,[object Object],[object Object],[object Object],[object Object]

[object Object],[object Object],Figure 40.7 Organic molecules in food Digestion and absorption Nutrient molecules in body cells Cellular respiration Biosynthesis: growth, storage, and reproduction Cellular work Heat Energy lost in feces Energy lost in urine Heat Heat External environment Animal body Heat Carbon skeletons ATP

[object Object],[object Object],[object Object],Quantifying Energy Use

[object Object],[object Object],Figure 40.8a, b This photograph shows a ghost crab in a respirometer. Temperature is held constant in the chamber, with air of known O 2 concentration flowing through. The crab’s metabolic rate is calculated from the difference between the amount of O 2 entering and the amount of O 2 leaving the respirometer. This crab is on a treadmill, running at a constant speed as measurements are made. (a) (b) Similarly, the metabolic rate of a man fitted with a breathing apparatus is being monitored while he works out on a stationary bike.

[object Object],[object Object],Bioenergetic Strategies

Stem Elongation ,[object Object],[object Object],[object Object]

[object Object],[object Object],Influences on Metabolic Rate

Size and Metabolic Rate ,[object Object],[object Object]

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Activity and Metabolic Rate

[object Object],[object Object],Figure 40.9 Maximum metabolic rate (kcal/min; log scale) 500 100 50 10 5 1 0.5 0.1 A H A H A A A H H H A = 60-kg alligator H = 60-kg human 1 second 1 minute 1 hour Time interval 1 day 1 week Key Existing intracellular ATP ATP from glycolysis ATP from aerobic respiration

[object Object],[object Object],Energy Budgets

[object Object],[object Object],Figure 40.10a, b Endotherms Ectotherm Annual energy expenditure (kcal/yr) 800,000 Basal metabolic rate Reproduction Temperature regulation costs Growth Activity costs 60-kg female human from temperate climate Total annual energy expenditures (a) 340,000 4-kg male Adélie penguin from Antarctica (brooding) 4,000 0.025-kg female deer mouse from temperate North America 8,000 4-kg female python from Australia Energy expenditure per unit mass (kcal/kg•day) 438 Deer mouse 233 Adélie penguin 36.5 Human 5.5 Python Energy expenditures per unit mass (kcal/kg•day) (b)

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[object Object],[object Object],Regulating and Conforming

[object Object],[object Object],Mechanisms of Homeostasis

[object Object],[object Object],Figure 40.11 Response No heat produced Room temperature decreases Heater turned off Set point Too hot Set point Control center: thermostat Room temperature increases Heater turned on Too cold Response Heat produced Set point

[object Object],[object Object],[object Object],[object Object],Ectotherms and Endotherms

[object Object],[object Object],Figure 40.12 River otter (endotherm) Largemouth bass (ectotherm) Ambient (environmental) temperature (°C) Body temperature (°C) 40 30 20 10 10 20 30 40 0

Modes of Heat Exchange ,[object Object],Figure 40.13 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. 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 . 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.

Balancing Heat Loss and Gain ,[object Object],[object Object]

Insulation ,[object Object],[object Object],[object Object]

[object Object],[object Object],Hair Sweat pore Muscle Nerve Sweat gland Oil gland Hair follicle Blood vessels Adipose tissue Hypodermis Dermis Epidermis Figure 40.14

[object Object],[object Object],Circulatory Adaptations

[object Object],[object Object],Figure 40.15 1 3 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. Canada goose Artery Vein 35°C Blood flow Vein Artery 30º 20º 10º 33° 27º 18º 9º Pacific bottlenose dolphin 2 1 3 2 3 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 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 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. 3

[object Object],[object Object],Figure 40.16a, b (a) Bluefin tuna. Unlike most fishes, the bluefin tuna maintains temperatures in its main swimming muscles that are much higher than the surrounding water (colors indicate swimming muscles cut in transverse section). These temperatures were recorded for a tuna in 19°C water. (b) Great white shark. Like the bluefin tuna, the great white shark has a countercurrent heat exchanger in its swimming muscles that reduces the loss of metabolic heat. All bony fishes and sharks lose heat to the surrounding water when their blood passes through the gills. However, endothermic sharks have a small dorsal aorta, and as a result, relatively little cold blood from the gills goes directly to the core of the body. Instead, most of the blood leaving the gills is conveyed via large arteries just under the skin, keeping cool blood away from the body core. As shown in the enlargement, small arteries carrying cool blood inward from the large arteries under the skin are paralleled by small veins carrying warm blood outward from the inner body. This countercurrent flow retains heat in the muscles. 21º 25º 23º 27º 29º 31º Body cavity Skin Artery Vein Capillary network within muscle Dorsal aorta Artery and vein under the skin Heart Blood vessels in gills

Cooling by Evaporative Heat Loss ,[object Object],[object Object],[object Object]

[object Object],[object Object],Behavioral Responses

Adjusting Metabolic Heat Production ,[object Object],[object Object]

[object Object],[object Object],Figure 40.20 PREFLIGHT PREFLIGHT WARMUP FLIGHT Thorax Abdomen Temperature (°C) Time from onset of warmup (min) 40 35 30 25 0 2 4

[object Object],[object Object],Feedback Mechanisms in Thermoregulation

[object Object],[object Object],Figure 40.21 Thermostat in hypothalamus activates cooling mechanisms. Sweat glands secrete sweat that evaporates, cooling the body. Blood vessels in skin dilate: capillaries fill with warm blood; heat radiates from skin surface. Body temperature decreases; thermostat shuts off cooling mechanisms. Increased body temperature (such as when exercising or in hot surroundings) 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.

Adjustment to Changing Temperatures ,[object Object],[object Object]

Torpor and Energy Conservation ,[object Object],[object Object],[object Object]

[object Object],[object Object],Additional metabolism that would be necessary to stay active in winter Actual metabolism Body temperature Arousals Outside temperature Burrow temperature June August October December February April Temperature (°C) Metabolic rate (kcal per day) 200 100 0 35 30 25 20 15 10 5 0 -5 -10 -15 Figure 40.22

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