Intro to Physiology

Question 1

What is physiology?

Answer 1

The branch of science that deals with the normal functioning of living organisms and their parts

Question 2

Define Pathophysiology

Answer 2

The mechanism by which a disease process causes the organ to fail

Question 3

Where does stomach acid come from?

Answer 3

Carbonic anhydrase reaction in Parietal cells frees up H+ ions. H+ is actively pumped out into the lumen

Question 4

Carbonic anhydrase reaction

Answer 4

CO2 + H2O -*> H2CO3 -> H+ + HCO3- REVERSIBLE

Question 5

Carbonic Anhydrase function

Answer 5

Contributes indirectly to H+ crossing cell membrane (& across epithelia) - H+ is charged and cannot cross readily cross cell membranes - CO2 is uncharged and readily crosses the membrane Helps indirectly to transport CO2 around body - CO2 is poorly soluble in blood - H+ and HCO3- are highly soluble

Question 6

Define homeostasis

Answer 6

is the regulation of the cell’s or the body’s internal environment (= extracellular fluid) so that it tends to maintain a stable, constant condition

Question 7

Feedback loop components

Answer 7

Sensor -> effector organ/physiological action -> physical change (response) -> Body parameter -> external cause -> physical change -> Perturbation (inside the body) -> Sensor

Question 8

Negative feedback loop general principles

Answer 8

stability - thermoregulation

opposing influences - insulin and glucagon

sensors - baroreceptors

Question 9

Positive feedback

Answer 9

positive feedback is when a small change is amplified and the initial stimulus causes further stimuli which intensifies until the stimulus is removed e.g. childbirth

Question 10

Positive feedback general principles

Answer 10

amplification - lactation and suckling

all or none - parturition

2 stages:

extrinsic (initiate), Intrinsic (amplify) - Action Potential Depolarisation