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