the cardiac cycle Flashcards
1
Q
describe the sinoatrial node
describe atrioventricular node
A
other wise known as that pace maker it initiates the the muscles contraction for the
2
Q
describe atrial systole
A
- lasts 0.1 seconds
- the atria contracts ventricles relax
- the SA node sends a nerve to the left and right atria causing a cardiac muscle contraction
- blood is then forced down to the ventricles which are in diastole (relaxed)
- the tricuspid valve is then open because the ventricles are relaxed
3
Q
how long does each cardiac cycle last on average
A
0.8 seconds
4
Q
define heart rate, cardiac output and stroke volume
A
heart rate: number of heart beats per minute (BPM)
cardiac output: the amount off blood pushed out of a ventricle one minute= heart rate x stroke volume. (ML/MIN)
stroke volume: the amount of blood pushed out of the ventricles in one contraction (ML)
5
Q
ventricular systole
A
- lasts 0.3 seconds
- ventricles contact arteria relaxes
- nerve impulses reach the AV node down the septum to the apex
- the impulse’s move up the perkinje fibers this the results in an upward contraction and blood is squeezed into the pulmonary arteries and the aorta
- the bicuspid valve closes as the blood is pumping to prevent backflow
6
Q
describe diastole
A
- both the atria and ventricles are relaxed
- the ti and bi cuspid valves are open and both atria and ventricles fill with blood.
7
Q
what is the average heart rate per minute
A
65-80 BPM
