5 Levels of Organization-

1) The body- 2) Organ systems-

3) Organ4) Tissue

muscle

skin

nerve

5) Cell-

Nerve cell Red blood cell

Muscle cell

Homeostasis- internal stability or "steady state" maintained by the body. (27-3)

1) no matter what the external temperature is, we keep our internal temperature at _______.98.6˚ F

- When cold, you must use ________ to create heat through the process of shivering

food

-When too warm, we __________.sweat

2) O2 vs. CO2 levels- job of the lungs and circulatory system. Information from brain sent to these organs by hormones to help balance O2 vs. CO2 hormones

3.) protection from the external world-

a.) skin-b.) Hair on head, nose, face

c) nailsd) mucus