Flashcards in Patient: DAB Physiol Lect 1: CVS review Deck (9):
Describe atrial systole
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)
Describe ventricular contraction
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
When is atrial systole eliminated from the cardiac cycle? is it fatal?
Not fatal. Elimination happens in the elderly sometimes
When is systemic arterial pressure at its minimum?
Min - Diastolic
Define cardiac output
What is the average cardiac output for a person at rest?
flow from one ventricle
=heart rate (beats/min) x Stroke Volume (mL)
about 5L/min in a person at rest
Typical heart rate?
Heart rate of a very fitness conscious person?
Heart rate of someone with CVD
80-100 is high and associated with CVD
>100 is Tachycardia