CHAPTER 40

BASIC PRINCIPLES OF ANIMAL FORM AND

FUNCTION

1

REVIEW:1. anatomy—study of an organism’s structure2. physiology—study of biological functionYou Must Know:3. Four types of tissues and their general functions4. The importance of homeostasis and examples5. How feedback systems control homeostasis, and

one example of positive feedback and one example of negative feedback

2

I. Concept 40.1

A. Tissues 1. Are defined as groups of cell that have a common structure

and function2. Can be organized into functional units called organs3. Groups of organs that work together make up organ systems

(Ex: digestive, circulatory, and excretory systems)

3

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

4

5

6

2. 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

7

8

9

10

11

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)

12

13

14

15

16

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

17

18

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

2. The Nervous System•Neurons transmit information between specific locations•Only three type of cells receive nerve impulses: neuron, muscle cells, and endocrine cells

19

20

II. Concept 40.2

A. 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

21

22

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

D. Positive Feedback•Involves a change in some variable that triggers mechanisms that amplify rather than reverse the change•Very unstable•Ex: uterine contractions

23

24

III. Concept 40.3

A. Thermoregulation—refers to how animals maintain their internal temperature within a tolerable range

B. Endotherms (warm blooded)•Ex: mammals and birds•Are warmed mostly by heat generated by metabolism

C. Ectotherms (cold blooded)•Ex: most invertebrates, fishes, amphibians, reptiles•Generate relatively little metabolic heat, gaining most of

their heat from external sources

25

26

27

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

28

Countercurrent Exchange

29