Cardiovascular Adaptions during Exercise (6)

Question 1

factors that explain large SV and low HR of endurance trained athletes

Answer 1

increased vagal tone and decreased sympathetic drive- slow HR
increased blood volume, myocardial contractility, and compliance of the left ventricle , all of which augment the heart’s stroke volume

Question 2

mechanisms that could increase the heart’s SV during exercise

Answer 2

1. enhanced cardiac filling in diastole followed by a more forceful systolic contraction
2. normal ventricular filling with subsequent more forceful ejection and emptying during systole
3. training adaptations that expand blood volume and reduce resistance to blood flow in peripheral tissues

Question 3

any factor that increases venous return or slows the heart produces

Answer 3

greater preload during the cardiac cycle’s diastolic phase

= more powerful ejection stroke during systole

Question 4

frank-starling law

Answer 4

force of contraction of cardiac muscle remains proportional to its initial resting length