Patient: DAB Physiol Lect 1: CVS review

Question 1

Describe atrial systole

Answer 1

Contraction starts in the atria
Additional flow into the ventricle due to the contraction of the atrium, along with a small rise in pressure
Ventricular volume has now reached its maximum point in the cycle - the “End-Diastolic Volume”
Ventricles remain relaxed at this stage (wave of electrical depolarisation is delayed at the A-V boundary)

Question 2

Describe ventricular contraction

Answer 2

Contraction of the ventricle starts
The rapid rise in pressure causes the AV (mitral) valve to snap shut, preventing backflow into the atrium
As pressure continues to rise, the aortic valve opens allowing flow into the aorta and downstream vessels
Ventricular volume decreases
As the contraction ends, ventricular pressure falls and the aortic valve snaps shut to prevent backflow from the arteries
the ventricular volume reaches its minimum value - the end-systolic volume

Question 3

When is atrial systole eliminated from the cardiac cycle? is it fatal?

Answer 3

Not fatal. Elimination happens in the elderly sometimes

Question 4

When is systemic arterial pressure at its minimum?

and maximum?

Answer 4

Min - Diastolic

Max- Systolic

Question 5

Define cardiac output

What is the average cardiac output for a person at rest?

Answer 5

flow from one ventricle
=heart rate (beats/min) x Stroke Volume (mL)
about 5L/min in a person at rest

Question 6

Typical heart rate?

Answer 6

70bpm

Question 7

Heart rate of a very fitness conscious person?

Answer 7

<60bpm

Question 8

Heart rate of someone with CVD

Answer 8

<60bpm=Bradycardia
80-100 is high and associated with CVD
>100 is Tachycardia

Question 9

Typical Stroke volume?

Answer 9

70mL