General physiology

Question 1

What metabolic factor is derived from break down of high energy phosphates, used by the coronary arteries for regulating flow?

Answer 1

Adenosine

Question 2

What is the name of the receptor on the sarcoplasmic reticulum? What binds to it and what is the result?

Answer 2

Ryanodine receptor
Bound by calcium entering the myocyte, triggers release of more calcium

Question 3

What is the role of ANP?

Answer 3

Released in response to atrial stretch
- Dilates afferent arteriole, constricts efferent arteriole increasing glomerular filtration
- Also involved in decreasing sodium resorption in the distal tubule

Question 4

How is the majority of calcium removed from the sarcoplasm during relaxation of cardiac muscle?

Answer 4

Actively via SERCA pumps on the sarcoplasmic reticulum (80%)
The other 20% is pumped out of the cell via channels

Question 5

Subunits of fetal hemoglobin vs. adult hemoglobin

Answer 5

Fetal: Alpha and gamma subunits (higher affinity for O2)
Adult: Alpha and beta subunits

Question 6

What is the effect of living at a high altitude on pulmonary pressures?

Answer 6

Higher PA pressures

Lower O2 => constriction of pulmonary vasculature => higher pulmonary pressures

Question 7

What does it mean to shift the hemoglobin dissociation curve to the right?

What four factors would move the curve to the right then?

Answer 7

Move to the right = decreased affinity of hemoglobin for O2, dropping more off

1) Increase in H+
2) Increased pCO2
3) Increased temperature
4) Increased BPG (increases when pO2 is low for a while)

Question 8

What occurs in phase 0 of a cardiac action potential?

Answer 8

Opening of the fast sodium channels with rapid depolarization

Question 9

What occurs in phase 1 of a cardiac action potential?

Answer 9

Initial repolarization by closing of the fast sodium channels, opening of some K channels

Question 10

What occurs in phase 2 of cardiac action potential?

Answer 10

Opening of slower calcium channels, resulting in a plateau to the repolarization
Closure of some of the initial potassium channels

Question 11

What occurs in phase 3 of the cardiac action potential?

Answer 11

Repolarization via closure of calcium channels and opening of K channels

Question 12

What occurs in phase 4 of the cardiac action potential?

Answer 12

Baseline resting conductance, as established by K channels

Question 13

Describe the different physiologic effects of Valsava vs hand grip

Answer 13

Valsava primarily decreases preload
Hand grip increases afterload

Question 14

What is the relationship between wall tension and radius of the ventricle?

Answer 14

Proportional

Question 15

What is the relationship between wall tension and the thickness of the ventricle?

Answer 15

Inverse

Question 16

What is a dietary change you can make when a patient has a chylous effusion?

Answer 16

Avoidance of long chain fatty acids, optimizing medium chain fatty acids