1. BASIC PRINCIPLES OF ANIMAL FORM AND FUNCTION
CHAPTER 40
BASIC PRINCIPLES OF ANIMAL FORM AND FUNCTION

2. REVIEW: anatomy—study of an organism’s structure
physiology—study of biological function
You Must Know:
Four types of tissues and their general functions
The importance of homeostasis and examples
How feedback systems control homeostasis, and one example of positive feedback and one example of negative feedback

3. I. Concept 40.1: Animal form and function are correlated at all levels of organization
Size and shape affect the way an animal interacts with its environment
Many different animal body plans have evolved and are determined by the genome
The ability to perform certain actions depends on an animal’s shape, size, and environment
Evolutionary convergence reflects different species’ adaptations to a similar environmental challenge
Physical laws impose constraints on animal size and shape

4. Mouth Gastrovascular cavity Exchange Exchange Exchange 0.15 mm 1.5 mm
Fig. 40-3
Mouth
Gastrovascular
cavity
Exchange
Exchange
Exchange
Figure 40.3 Contact with the environment
0.15 mm
1.5 mm
(a) Single cell
(b) Two layers of cells

5. Multicellular organisms with a sac body plan have body walls that are only two cells thick, facilitating diffusion of materials
More complex organisms have highly folded internal surfaces for exchanging materials
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6. Figure 40.4 Internal exchange surfaces of complex animals
External environment
CO2
Food O2
Mouth
Animal
body
Respiratory
system
Blood
50 µm
0.5 cm
Lung tissue
Nutrients
Cells
Heart
Circulatory
system
10 µm
Interstitial
fluid
Digestive
system
Figure 40.4 Internal exchange surfaces of complex animals
Lining of small intestine
Excretory
system
Kidney tubules
Anus
Unabsorbed
matter (feces)
Metabolic waste products
(nitrogenous waste)

7. Metabolic waste products (nitrogenous waste)
Fig. 40-4a
External environment
CO2
Food O2
Mouth
Animal
body
Respiratory
system
Blood
Nutrients
Cells
Heart
Circulatory
system
Interstitial
fluid
Digestive
system
Figure 40.4 Internal exchange surfaces of complex animals
Excretory
system
Anus
Unabsorbed
matter (feces)
Metabolic waste products
(nitrogenous waste)

8. Lining of small intestine
Fig. 40-4b
0.5 cm
Figure 40.4 Internal exchange surfaces of complex animals
Lining of small intestine

9. Fig. 40-4c
50 µm
Lung tissue
Figure 40.4 Internal exchange surfaces of complex animals

10. Kidney tubules 10 µm Fig. 40-4d
Figure 40.4 Internal exchange surfaces of complex animals
Kidney tubules

11. In vertebrates, the space between cells is filled with interstitial fluid, which allows for the movement of material into and out of cells
A complex body plan helps an animal in a variable environment to maintain a relatively stable internal environment
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12. Hierarchical Organization of Body Plans
Most animals are composed of specialized cells organized into tissues that have different functions
Tissues make up organs, which together make up organ systems
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13. Tissues
1. Are defined as groups of cell that have a common structure and function
2. Can be organized into functional units called organs
3. Groups of organs that work together make up organ systems (Ex: digestive, circulatory, and excretory systems)

14. B. Four types of tissue:
1. Epithelial Tissue
Occurs in sheets of tightly packed cells
Covers the body, lines the organs and acts as a protective barrier
One side of the epithelium is always bound to an underlying surface called the basement membrane (basal surface)
Always has one free surface facing either air or a fluid environment

15. It contains cells that are closely joined
The shape of epithelial cells may be cuboidal (like dice), columnar (like bricks on end), or squamous (like floor tiles)
The arrangement of epithelial cells may be simple (single cell layer), stratified (multiple tiers of cells), or pseudostratified (a single layer of cells of varying length)
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18. Connective Tissue
Mainly supports and binds other tissues
Consists of scattered cells within an extracellular matrix
Ex: cartilage, tendons, ligaments, bone, adipose tissue, and blood

19. There are three types of connective tissue fiber, all made of protein:
Collagenous fibers provide strength and flexibility
Elastic fibers stretch and snap back to their original length
Reticular fibers join connective tissue to adjacent tissues
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20. Connective tissue contains cells, including
Fibroblasts that secrete the protein of extracellular fibers
Macrophages that are involved in the immune system
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21. In vertebrates, the fibers and foundation combine to form six major types of connective tissue:
Loose connective tissue binds epithelia to underlying tissues and holds organs in place
Cartilage is a strong and flexible support material
Fibrous connective tissue is found in tendons, which attach muscles to bones, and ligaments, which connect bones at joints
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22. Adipose tissue stores fat for insulation and fuel
Blood is composed of blood cells and cell fragments in blood plasma
Bone is mineralized and forms the skeleton
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27. 3. Muscle Tissue
Responsible for nearly all types of body movement
Muscle filaments are made of the proteins actin (thin) and myosin (thick)
Muscle fibers contract when stimulated by a nerve impulse
Most abundant tissue in most animals
Three types of muscle: skeletal (voluntary), cardiac (involuntary—makes up heart), smooth (involuntary)

28. Muscle Tissue It is divided in the vertebrate body into three types:
Skeletal muscle, or striated muscle, is responsible for voluntary movement
Smooth muscle is responsible for involuntary body activities
Cardiac muscle is responsible for contraction of the heart
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33. 4. Nervous Tissue Functional unit is the neuron (nerve cell)
Senses stimuli and transmits signals from one part of the body to another part
Includes other neurons, glands, muscles and the brain

35. C. For animal survival tissue, organs, and organ systems
C. For animal survival tissue, organs, and organ systems must act in a coordinated manner
1. The Endocrine System
Involves glands that produce chemicals called hormones that are released into the bloodstream and carried to specific glands
A hormone may affect one or more regions throughout the body
Hormones are relatively slow acting, but can have long-lasting effects

36. C. For animal survival tissue, organs, and organ systems
C. For animal survival tissue, organs, and organ systems must act in a coordinated manner
2. The Nervous System
Neurons transmit information between specific locations
Only three type of cells receive nerve impulses: neuron, muscle cells, and endocrine cells

38. II. Concept 40.2 Homeostasis
Process by which animals maintain a relatively constant internal environment, even when the external environment changes significantly
“steady state”
B. Homeostatic control systems function by having a set point (body temperature), sensors to detect any stimulus above or below the set point, and a physiological response that helps return the body to its set point

40. C. Negative Feedback
Animal response to the stimulus in a way that reduces the stimulus
Ex: in response to exercise, the body temperature rises, which initiates sweating to cool the body
Positive Feedback
Involves a change in some variable that triggers mechanisms that amplify rather than reverse the change
Very unstable
Ex: uterine contractions

41. Alterations in Homeostasis
Set points and normal ranges can change with age or show cyclic variation
Homeostasis can adjust to changes in external environment, a process called acclimatization
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43. III. Concept 40.3
Thermoregulation—refers to how animals maintain their internal temperature within a tolerable range
Endotherms (warm blooded)
Ex: mammals and birds
Are warmed mostly by heat generated by metabolism
Ectotherms (cold blooded)
Ex: most invertebrates, fishes, amphibians, reptiles
Generate relatively little metabolic heat, gaining most of their heat from external sources

44. Endothermy is more energetically expensive than ectothermy
In general, ectotherms tolerate greater variation in internal temperature, while endotherms are active at a greater range of external temperatures
Endothermy is more energetically expensive than ectothermy
The body temperature of a poikilotherm varies with its environment, while that of a homeotherm is relatively constant
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47. Balancing Heat Loss and Gain
Organisms exchange heat by four physical processes: conduction, convection, radiation, and evaporation
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48. Radiation Evaporation Convection Conduction Fig. 40-10
Figure Heat exchange between an organism and its environment
Convection
Conduction

49. Heat regulation in mammals often involves the integumentary system: skin, hair, and nails
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50. Hair Epidermis Sweat pore Dermis Muscle Nerve Sweat gland Hypodermis
Fig
Hair
Epidermis
Sweat
pore
Dermis
Muscle
Nerve
Sweat
gland
Figure Mammalian integumentary system
Hypodermis
Adipose tissue
Blood vessels
Oil gland
Hair follicle

51. Five general adaptations help animals thermoregulate:
Insulation
Circulatory adaptations
Cooling by evaporative heat loss
Behavioral responses
Adjusting metabolic heat production
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52. Insulation
Insulation is a major thermoregulatory adaptation in mammals and birds
Skin, feathers, fur, and blubber reduce heat flow between an animal and its environment
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53. Circulatory Adaptations
Regulation of blood flow near the body surface significantly affects thermoregulation
Many endotherms and some ectotherms can alter the amount of blood flowing between the body core and the skin
In vasodilation, blood flow in the skin increases, facilitating heat loss
In vasoconstriction, blood flow in the skin decreases, lowering heat loss
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54. D. Countercurrent Exchange
This is the method by which many birds and mammals reduce heat loss
Heat transfer involves antiparallel arrangement of blood vessels such that warm blood from the core of the animal, en route to the extremities, transfers heart to colder blood returning form the extremities.
Heat that would have been lost to the environment is conserved in the blood returning to the core of the animals

55. Countercurrent Exchange

56. Cooling by Evaporative Heat Loss
Many types of animals lose heat through evaporation of water in sweat
Panting increases the cooling effect in birds and many mammals
Sweating or bathing moistens the skin, helping to cool an animal down
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57. Behavioral Responses
Both endotherms and ectotherms use behavioral responses to control body temperature
Some terrestrial invertebrates have postures that minimize or maximize absorption of solar heat
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58. Fig
Figure Thermoregulatory behavior in a dragonfly

59. Adjusting Metabolic Heat Production
Some animals can regulate body temperature by adjusting their rate of metabolic heat production
Heat production is increased by muscle activity such as moving or shivering
Some ectotherms can also shiver to increase body temperature
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60. Concept 40.4: Energy requirements are related to animal size, activity, and environment
Bioenergetics is the overall flow and transformation of energy in an animal
It determines how much food an animal needs and relates to an animal’s size, activity, and environment
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61. Energy Allocation and Use
Animals harvest chemical energy from food
Energy-containing molecules from food are usually used to make ATP, which powers cellular work
After the needs of staying alive are met, remaining food molecules can be used in biosynthesis
Biosynthesis includes body growth and repair, synthesis of storage material such as fat, and production of gametes
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62. Organic molecules in food External environment Animal body
Fig
Organic molecules
in food
External
environment
Animal
body
Digestion and
absorption
Heat
Energy lost
in feces
Nutrient molecules
in body cells
Energy lost in
nitrogenous
waste
Carbon
skeletons
Cellular
respiration
Heat
Figure Bioenergetics of an animal: an overview
ATP
Biosynthesis
Cellular
work
Heat
Heat

63. Quantifying Energy Use
Metabolic rate is the amount of energy an animal uses in a unit of time
One way to measure it is to determine the amount of oxygen consumed or carbon dioxide produced
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64. Fig
Figure Measuring rate of oxygen consumption in a running pronghorn

65. Minimum Metabolic Rate and Thermoregulation
Basal metabolic rate (BMR) is the metabolic rate of an endotherm at rest at a “comfortable” temperature
Standard metabolic rate (SMR) is the metabolic rate of an ectotherm at rest at a specific temperature
Both rates assume a nongrowing, fasting, and nonstressed animal
Ectotherms have much lower metabolic rates than endotherms of a comparable size
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66. Influences on Metabolic Rate
Metabolic rates are affected by many factors besides whether an animal is an endotherm or ectotherm
Two of these factors are size and activity
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67. Size and Metabolic Rate
Metabolic rate per gram is inversely related to body size among similar animals
Researchers continue to search for the causes of this relationship
The higher metabolic rate of smaller animals leads to a higher oxygen delivery rate, breathing rate, heart rate, and greater (relative) blood volume, compared with a larger animal
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68. Activity and Metabolic Rate
Activity greatly affects metabolic rate for endotherms and ectotherms
In general, the maximum metabolic rate an animal can sustain is inversely related to the duration of the activity
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69. Energy Budgets
Different species use energy and materials in food in different ways, depending on their environment
Use of energy is partitioned to BMR (or SMR), activity, thermoregulation, growth, and reproduction
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70. Torpor and Energy Conservation
Torpor is a physiological state in which activity is low and metabolism decreases
Torpor enables animals to save energy while avoiding difficult and dangerous conditions
Hibernation is long-term torpor that is an adaptation to winter cold and food scarcity
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71. Estivation, or summer torpor, enables animals to survive long periods of high temperatures and scarce water supplies
Daily torpor is exhibited by many small mammals and birds and seems adapted to feeding patterns
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72. Stimulus: Perturbation/stress
Fig. 40-UN1
Homeostasis
Response/effector
Stimulus:
Perturbation/stress
Control center
Sensor/receptor