Homeostasis

Question 1

Definition

Answer 1

The body’s maintenance of a stable internal environment despite an ever-changing outside environment

Question 2

Internal Environment

Answer 2

a. fluids in which body cells live- extracellular fluid (interstitial fluid & blood plasma)
- sugars, proteins, fats, diffuse into skin/extracellular fluid
- plasma in blood mirrors cytoplasm of the cells
b. internal environment must contain appropriate concentration of chemicals & must be at the right temperature/pressure
c. dynamic process, always adjusting

Question 3

What throws Homeostasis off?

Answer 3

Stress- any stimulus that creates an imbalance in the internal environment that disrupts homeostasis
Ex:
- external: heat, cold, pressure, oxygen levels
- internal: tumor, blood pressure, emotional distress

Question 4

Homeostasis Mechanisms

Answer 4

Body’s way of correcting imbalances (controlled by endocrine & nervous system):
- Stimulus: light (chem, pain, touch, sound)
- Receptor: photoreceptor (sends message to CC)
- Control Center: brain (receives message)
- Effector: muscle or gland
- Response: movement or secretion

Question 5

Negative Feedback

Answer 5

Coming back to normal (homeostasis)
a. Most common type of feedback
- Control of body temperature
- Thirsty
- Cold (shiver)
- Control of blood sugar

Question 6

Positive Feedback

Answer 6

Moves system away from normal & output intensifies input (stimulus)
- Usually temporary in response to injury or crisis
ex: wound healing, labor/delivery
- Oxytocin: during labor/delivery
- Disease= result of homeostatic imbalance