cardiac output

Question 1

cardiac output equation

Answer 1

cardiac output (cm3 min-1) = stroke volume (cm3) x heart rate (bpm)

Question 2

what is cardiac output

Answer 2

the total volume of blood pumped out by the heart in one minute

Question 3

what is stroke volume

Answer 3

the amount of blood pumped out of the left ventricle in one pump

Question 4

what does myogenic mean

Answer 4

the contraction of muscle without receiving any stimulus from the nervous system as the nerve impulse is generated by the cardiac muscle itself

Question 5

sequence of events to cause a heart best

Answer 5

1. the SAN generates an electrical impulse which spreads across the atria walls causing them to contract
2. a band of non-conducting collagen tissue prevents the impulses being transferred directly to the ventricles
3. the impulse is channelled to the AVN and then through the bundle of his
4. from the bundle of his the impulse is transmitted via the purkyne fibres from the apex of the ventricles and upwards
5. both ventricles contract simultaneously from the apex upwards and blood is pushed out of the ventricles into the aorta and pulmonary artery

Question 6

why is there a delay between the impulse reaching the AVN

Answer 6

to allow for the atria to empty fully into the ventricles