4.1 - Cardiovascular Review

Question 1

Smooth muscle contraction is triggered by calcium entry into the cell, what does it bind to then?

Answer 1

Calmodulin - secondary messenger

Question 2

What happens after Calcium binds to calmodulin in smooth muscle contraction?

Answer 2

It forms a complex: Myosin light chain kinase (MLCK)
–> MLCK stimulates phosphorylation of myosin which activates it. Activated myosin forms a cross bridge with actin (contraction)

Question 3

What factors stimulate contraction of smooth muscle in BVs?

Answer 3

–> Increased intracellular calcium
–> Increased AngII or NA in plasma
–> Stimulation of Alpha 1 agonist

Question 4

What factors stimulate relaxation of vascular smooth muscle?

Answer 4

–> Decreased intracellular calcium
–> Stimulation of beta2 receptors
–> Any drug than increases intracellular cAMP or cGMP levels
–> Increased nitric oxide

Question 5

What causes angina?

Answer 5

Ischemia of heart tissue d/t oxygen utilization by the heart exceeding the oxygen delivery to the heart via the coronaries.

Question 6

What are the three kinds of angina?

Answer 6

Stable - usually occurs with physical exertion, emotional stress, or other triggers than increase the heart’s workload

Variable/Prinzmetal - D/t vasospasm, unpredictable

Unstable - Occurs more frequently, lasts longer, and it often not relieved by rest. May represent a pre-myocardial infarction state.

Question 7

What can we do to increase O2 oxygen delivery to the heart to treat angina?

Answer 7

Reperfusion through:
–> Angioplasty (remove blockage or stent)
–> Coronary bypass
–> Reversal of vasospasm pharmaceutically

Question 8

How can we decrease oxygen utilization by the heart to treat angina?

Answer 8

by decreasing:
–> Heart performance (contractility)
–> Heart rate
–> Blood pressure (Afterload)
–> Heart filling/venous return (Preload)

Question 9

What four variables control heart oxygen utilization?

Answer 9

–> Contractility
–> Heart rate
–> Afterload (The pressure required to open the aortic valve)
–> Preload (Pressure on ventricular walls by end diastole)

Question 10

What is afterload?

Answer 10

The pressure or work required to open the aortic valve d/t pressure at the arteriole level
—> Prof uses example of blowing air through carboard tube vs small straw

Question 11

What is preload?

Answer 11

The amount of force on the ventricular walls during filling
–> Influenced by the end diastolic volume
–> A vehicle carrying a full load consumes for gasoline