Bi 103 Notes: Chapter 27: Animal Homeostasis and Organization

I. Organization of the Animal Body

A. Tissue: Cells that are similar in structure and perform a specialized function.

1. Epithelial Tissue

a) Covers body surface, lines body cavities

b) Form glands: Exocrine and Endocrine

c) Continually replaced by mitosis.

Examples

1) Skin: forms impermeable barrier

2) Intestinal lining: permeable barrier

3) Lung lining: Self-cleaning barrier

2. Connective Tissue

a) Function: Binds/supports other tissues,

b) Consists of cells & extracellular material (i.e. collagen)

Types:

1) Loose connective tissue (i.e. beneath skin)

2) Fibrous connective tissue (i.e. ligaments and tendons)

3) Specialized connective tissue

a) Cartilage: cushions, flexible support

b) Bone: protection, support- allows movement

c) Fat (Adipose): storage, insulation

d) Blood: protection, transport

3. Muscle Tissue

a) Cells which contract when stimulated

Types:

1) Skeletal muscle: voluntary control

2) Cardiac muscle: involuntary control

3) Smooth muscle: involuntary control

4. Nervous Tissue

a) Cells which can conduct electrical impulses

b) In brain, spinal cord, peripheral nerves

Cell Types:

1) Neurons (generate/conduct impulse)

2) Glial cells (support & protect neurons)

B. Organ: Structure with 2+ tissues that function together.

1) Example: Skin

C. Organ System: 2+ organs cooperating to achieve a function

1) Example: Digestive system

II. Homeostasis

A. The process of maintaining a relatively stable internal environment

1) Dynamic equilibrium (always under adjustment)

B. Maintained by feedback systems (have sensor, control center, effector)

1) Negative Feedback (see figure 27.1)

a) Effector counteracts change detected by sensor

2) Positive Feedback (see figure 27.1)

a) Promotes change to a conclusion (i.e. childbirth)

C. Communication Systems are Critical to Maintain Homeostasis

1) Nervous System

a) Electrical communication via nerve/muscle tissue : Fast; Short duration

2) Endocrine System

a) Chemical communication via bloodstream: Slow; Long duration