Intro To Physiology And Homeostasis

Question 1

What is physiology?

Answer 1

The study of normal functioning of a living organism and its component parts, including all its chemical and physical processes

Question 2

Why is physiology an integrative science?

Answer 2

1. Encompasses many disciplines
   - closely tied to anatomy (structure dictates function)
2. Contains emergent properties
   - complex system that cannot be explained by knowledge of individual components
3. Integration between organ systems
   - any process involves multiple organ systems

Question 3

What are the levels of organization?

Answer 3

Chemistry, molecular biology, cell biology, physiology, ecology

Question 4

Do physiologists focus on function(teleological approach) or mechanistic approach

Answer 4

Mechanistic approach (how)

Question 5

What is homeostasis?

Answer 5

Ability to maintain a relatively stable internal environment despite exposure to external variability (blood pressure, body temp, ion/molecule concentration, gas partial pressures,etc.)

Question 6

What is pathophysiological state?

Answer 6

When organism attempts to compensate after loss of homeostasis but compensation fails and results in illness or disease

Question 7

Why must we maintain stable internal environment?

Answer 7

Constancy is important; most cells are not tolerant to changes in surroundings

Question 8

What is the law of mass balance?

Answer 8

If the amount of a substance in the body is to remain constant, any gain must be offset by an equal loss and any gain must be offset by a loss
Ex) excess water, urination and sweating

Question 9

Why is ECF and ICF in homeostasis not mean equilibrium?

Answer 9

Body compartments are in dynamic steady state but are not in equilibrium but rather disequilibrium

Question 10

How is homeostasis maintained?

Answer 10

Control systems (local or reflex)

Question 11

What is local control?

Answer 11

Restricted to tissues or cell involved

Question 12

What is reflex control?

Answer 12

Uses long distance signalling (systemic). Refers to any long-distance pathway that uses nervous, endocrine system or both
2 parts: response loop and feedback loop

Question 13

What is feedback loop?

Answer 13

Modulates response loop (changes stimulus)
Feeds back to influence the input
Can be antagonistic

Question 14

Negative feedback loop?

Answer 14

A pathway where the response opposes or removes the stimulus signal
Homeostatic (stabilizes a system)

Question 15

Positive feedback loop?

Answer 15

Not homeostatic. Reinforces a stimulus to drive the system away from normal value, requires intervention outside the loop to cease response

Question 16

Feedforward control?

Answer 16

Reflexes that allow body to predict change is about to occur (anticipatory)

Question 17

What are biological rhythms?

Answer 17

Variables that change predictably and create repeating patterns or cycles of changes