3. Homeostasis

Feedback

an organs Reponses to the change in environment

Inhibitory response example

EG insulin released when blood sugar levels spike

Amplification response example

after ingesting food, pepsinogen released is converted to pepsin which aids food digestion and triggers further pepsin conversion

feedforward/Cephalic response

a system output that anticipates physiological changes and responds accordingly

EG: salivating at the smell of food/gag reflex

homeostasis

body system adjusting to external systems in order to maintian internal conditions

examples of homeostasis

blood pressure

temperature

pH

Electrolytes (Na/K, maintains certain impulses)

Examples of feedback

1. goosebumps when too cold

2. shivering

3. releasing ADH

4. vasodilatation

5. vasoconstriction

Allostasis

a process for actively maintaining homeostasis through changes in response to stressors

Examples of allostasis

1. increased blood flow when exercising 

2. body’s response to a cut

3. body producing calloses in response to friction of foot against shoe

4. bears increasing body fat before hibernation

5. fight/ flight

Different types of allostasis

• Acute

• repetitive

• Chronic

• Cumulative

Acute allostasis

one time response

Repetitive allostasis

same response more than once

Chronic allostasis

same response over a long period of time

Cumulative allatosis

Different allostatic responses over a long time period, the majority of a lifetime