1. Unifying Concepts of Animal Structure and Function
CHAPTER 21
Unifying Concepts of Animal Structure and Function

6. Biology and Society: Keeping Cool
This soccer player just finished a rigorous game.
His body heated up, but his body temperature didn’t rise significantly.
Evaporation of sweat cooled the skin.
Surface blood vessels widened to allow heat to escape.
Copyright © 2007 Pearson Education Inc., publishing as Pearson Benjamin Cummings

7. Figure 21.1

8. Under extreme conditions, his body could lose the ability to regulate its temperature.
This condition is called heat stroke.

9. The Structural Organization of Animals
Life is characterized by a hierarchy of organization.
In animals,
Individual cells are grouped into tissues.
Tissues combine to form organs.
Organs are organized into organ systems.
Organ systems make up the entire organism.

10. Figure 21.2

11. Form Fits Function
Analyzing a biological structure gives us clues about what it does and how it works.

12. Figure 21.3

13. Biologists distinguish anatomy from physiology.
Anatomy is the study of the structure of an organism
Physiology is the study of the function of an organisms structure

14. In most multicellular animals, cells are grouped into tissues.
A tissue is an integrated group of similar cells that perform a specific function.

15. Epithelial tissue, also called epithelium,
Covers the surface of the body
Lines organs and cavities with in the body

16. Figure 21.4

17. Epithelial tissue is made of sheets of tightly packed cells.
The cells are riveted together in a continuous layer.
The body continuously renews surface-lining epithelium.

18. The structure of connective tissue correlates with its function.
Connective tissues have a sparse population of cells scattered through an extra cellular matrix
The matrix consists of a web of protein fibers embedded in a uniform foundation.
The structure of connective tissue correlates with its function.
It binds and supports other tissues

19. Figure 21.5

20. Loose connective tissue is the most widespread connective tissue.
Connective tissue - types
Loose connective tissue is the most widespread connective tissue.
It binds epithelia to underlying tissues
It holds organs in place

21. Adipose tissue stores fat.
Connective tissue - types
Adipose tissue stores fat.
It stockpiles energy
It pads and insulates the body.

22. Blood is a connective tissue with a matrix of liquid
Connective tissue - types
Blood is a connective tissue with a matrix of liquid
Red and white blood cells are suspended in plasma
Transports food and gases

23. Fibrous connective tissue has a dense matrix of collagen
Connective tissue - types
Fibrous connective tissue has a dense matrix of collagen
It forms tendons & ligaments

24. The matrix of cartilage is strong but rubbery.
Connective tissue - types
The matrix of cartilage is strong but rubbery.
It functions as a flexible, boneless skeleton
It forms the shock-absorbing pads that cushion the vertebrae of the spinal column.

25. Connective tissue - types
Bone is a rigid connective tissue with a matrix of rubbery fibers hardened w/ deposits of calcium

26. Muscle Tissue
Muscle tissue consists of bundles of long, thin, cylindrical cells called muscle fibers
Each cell has specialized proteins that contract when the cell is stimulated by a nerve.

27. Figure 21.6

28. Skeletal muscle is attached to bones by tendons.
It is responsible for voluntary movements.
The contractile apparatus forms a banded pattern in each cell or fiber.
It is said to be striated or striped

29. Cardiac muscle is found only in heart tissue.
Its contraction accounts for the heartbeat.
Cardiac muscle cells are branched & joined to one another
Striated muscle not made of muscle fibers

30. Smooth muscle is named for its lack of obvious striations
It is found in the walls of various organs.
It is involuntary
intestines

31. Nervous tissue makes communication of sensory information possible.
Sensory input is received and processed.
Motor output is then relayed to make body parts respond.
Nervous tissue is found in the brain & spinal cord

32. The basic unit of nervous tissue is the neuron, or nerve cell.
Neurons can transmit electrical signals rapidly over long distances.

33. Organs and Organ Systems
The next level in the structural hierarchy is the organ.
An organ consists of two or more tissues packed into one working unit the performs a specific function
Examples: heart. liver. stomach. brain. lungs.

34. Figure 21.7

35. The organs of humans and most other animals are organized into organ systems.
Organ systems are teams of organs that work together to perform a vital bodily function

36. Figure 21.8 part 1

37. Figure 21.8 part 2

38. Figure 21.8 part 3

39. Figure 21.8 part 4

40. Figure 21.8 part 5

41. Figure 21.8 part 6

42. Figure 21.8 part 7

43. How organisms interact with their environment

44. Exchanges with the External Environment
Every organism is an open system.
This means that organisms continuously exchange chemicals and energy with their surroundings.
Organisms must do this to survive.

45. An animal’s size and shape affect how it exchanges energy and materials with its surroundings.
All living cells must be bathed in a watery solution so that exchange of material can occur

46. Exchange with the environment is easy for single-celled organisms.
The entire surface area of an amoeba is in contact with the environment.

47. Figure 21.9a

48. A hydra has a body wall only two cell layers thick.
Both layers are bathed in pond water, enabling exchange with the environment.

49. Figure 21.9b

50. Animals with complex body forms face the same basic problem.
Every living cell must be bathed in fluid
Every cell must have access to essential nutrients from the outside environment
Complex animals have extensively folded or branched internal surfaces
These maximize surface area for exchange with the environment.

51. Lungs exchange oxygen and carbon dioxide with the air.
The epithelium of the lungs has a very large total surface area for this purpose.

52. Figure 21.10

53. Examples of the exchange of materials with the external environment

54. Figure 21.11

55. Regulating the Internal Environment
Every living organism has the ability to respond to its environment.
How do animals adjust to changing environmental conditions?
homeostasis

56. Homeostasis
Homeostasis is the body’s tendency to maintain relatively constant conditions in the internal environment even when the external environment changes

57. Figure 21.12

58. Negative and Positive Feedback
Most mechanisms of homeostasis depend on a common principle called negative feedback
The results of some process inhibit that very process.
Negative Feedback
Positive Feedback

59. Figure 21.13

60. Less common is positive feedback.
The results of a process intensify that same process.
Example: uterine contractions during childbirth

61. Thermoregulation is the maintenance of internal body temperature.
Endotherms derive the majority of their body heat from their metabolism.
Ectotherms obtain body heat primarily by absorbing it from their surroundings.

62. Humans and other animals have a number of structures and mechanisms that aid in thermoregulation.

63. Figure part 1

64. Figure part 2

65. Fever is an abnormally high internal temperature.
It is a body-wide response that usually indicates an ongoing fight against infection.

66. In addition to the brain’s temperature control center,
A number of other mechanisms help animals cope with heat gained from or lost to the environment.

67. Figure 21.15

68. Living cells depend on a precise balance of water and solutes.
Osmoregulation
Living cells depend on a precise balance of water and solutes.
Osmoregulation is the control of the gain or loss of the gain or loss of water and dissolved soluted

69. Osmoronformers Osmoregulators
Are organisms whose internal and external environments have similar solute concentrations.
Include most marine invertebrates.
Osmoregulators
Are organisms who actively regulate their water loss or gain.
Include freshwater animals and most marine vertebrates, as well as all land animals.

70. Homeostasis in Action: The Urinary System
The urinary system plays a central role in homeostasis.
It forms and excretes urine while regulating the amount of water and solutes in body fluids.

71. In the human urinary system, the main processing centers are the two kidneys.
The kidneys contain many fine tubes (tubules) and an intricate network of capillaries.

72. The anatomy of the human urinary system
Nephron Introduction

73. Figure 21.16a, b

74. Nephrons are the functional units of the kidneys.
Hormonal control of the nephrons allows the body to control its internal concentration of water and dissolved molecules.

75. Figure 21.16c

76. The kidneys perform four excretory functions.
Bowman’s Capsule and Proximal Tubule
Loop of Henle and Distal Tubule
Collecting Duct
Effect of ADH

77. Skip !!!!!!!!!!!!!!!!!!!!!!
Figure 21.17

78. Kidney failure can be caused by injury, illness, or many other factors.
One option for treatment of kidney failure is dialysis.

79. Figure 21.18

80. Evolution Connection: How Physical Laws Limit Animal Form
An animal’s ability to exchange materials with the environment is limited by physical laws.
Physical requirements constrain what natural selection can “invent.”
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81. The constraints of the physical world account for the similarity among aquatic swimmers.
This is an example of Convergent Evolution

82. Figure 21.19