Environmental demands on CV system (week 12) FINISHED

Question 1

How does the myocardium respond to exercise?

Answer 1

Thickness varies directly with stress on the chamber walls.

With vigorous exercise, the left ventricle size increases.
Increase is due to increased ventricular volume.

Question 2

What is the CV response to acute exercise?

Answer 2

SNS activation

Vasodilation of vessels in skeletal muscles, beta 2 receptors + coronary arteries = increased blood flow to skeletal and heart muscles

Vasoconstriction in the rest of the vascular system = increase in MAP and increase in the circulating volume from veins.

Increase in HR, SV = increase in CO

Question 3

What is the resting value of CO?

Answer 3

5L/min

Question 4

When do the increased of CO become more a result of HR than of SV?

Answer 4

When exercise intensity exceeds 40%-60%

Question 5

What is CV drift?

Answer 5

Gradual decrease in SV and systemic MAP and pulmonary arterial pressures and an increase in HR.

Occurs with steady-state prolonged exercise of exercise in a hot environment