CHAPTER 20

Animal Structure & Function

Anatomy: study of an organism’s structures

Physiology: study of the functions of an organism’s structures

Levels of Structural Organization

•Tissues – a cooperative unit of many very similar cells that perform a specific function

-Epithelial -Connective -Muscle -Nervous

Sect 20.2-20.3

Epithelial tissue occurs in sheets of closely packed cells that covers the body & lines internal organs

• Simple - single layer

• Stratified -multiple layers

• Squamous - floor tile

• Cuboidal - dice• Columnar - bricks

Mucous membrane – smooth, moist epithelium that lines digestive tract & air tubes leading to lungs (secretes slimy soln that lubricates & keeps a surface moist)

Sect 20.4

Simple Squamous

Simple Cuboidal

Simple Columnar

Stratified Squamous

Stratified Cubodial

Stratified Columnar

Connective tissue consists of a sparse population of cells scattered through a nonliving substance called matrix• Loose connective tissue – binding &

packaging material, holding other organs & tissues in place

• Adipose tissue – contains fat, pads, insulates body, stores fuel molecules

Sect 20.5

•Fibrous connective tissue – has a matrix of densely packed parallel bundles of collagen

- tendons – join muscles to bone - ligaments – join bones to bones

at joints

•Cartilage – flexible & strong support material

•Bone – mineralized that is very rigid (but not brittle unless lack of Calcium)

•Blood – liquid matrix known as plasma

Muscle tissue – bundles of long, excitable cells called muscle fibers that are capable of contraction

•Skeletal muscle – attached to bones (striated, voluntary) Sect

20.6

Cardiac muscle – forms the walls of heart (striated, involuntary)

Smooth muscle – found in walls of digestive tract, bladder, & other internal organs (involuntary)

Nervous tissue forms the communication system that transmits information as nerve signals

•Neurons – functional units of nervous tissue

•Support tissues – nourish & insulate

Sect 20.7

Organs

•Made up of different tissues organized for a specific function - mesenteries are membranes that suspend many organs

- 2 body cavities that house the organs

- diaphragm - sheet of muscle that separates the 2 cavities

Sect 20.9

Body Cavities•Thoracic Cavity - upper

cavity•Abdominal Cavity - lower

cavity

Organ Systems

•Consists of several organs working toward the same function

•12 organ systems in human body:

Sect 20.10

12 Organ Systems1. Digestive Circulatory

p. 420-4212. Respiratory3. Cardiovascular4. Lymphatic5. Immune6. Excretory7. Reproductive8. Endocrine9. Nervous10. Muscular11. Skeletal12. Integumentary

Exchange w/Environment(Internal Environment)

• Interstitial fluid - bathes the cells• direct exchange does not occur

between blood and cells that make up tissues and organs

• blood - body cells- blood

Sect 20.12

Regulation

• Internal environment of an animal always fluctuates slightly

- in response to external conditions

- homeostasis - ability to maintain a constant environment

Sect 20.13

•Humans maintain homeostasis based on negative feedback: a change in internal or external environment causes processes to reverse that change

•similar to a thermostat•controls things like temp., pH,

[salt]