Question

If the heart rate increases to very high level, then

Question 17 options:

	a) the oxygen constant of the blood falls to levels insufficient to maintain cardiac activity
	b) end-diastlic volume drops because ventricular filling time is so short
	c) end-systolic volume increases because the valves are open for only a short time
	d) the autonomic nervous system will release more epinephrine to the sinoatrial node to stabilize the heart rate
	e) stroke volume increases to keep cardiac output constant

Answer 1

If the heart rate increases to a very high level, then end diastolic volume drop because ventricular filing time is so short. Hence , option b is correct.