cardiac cycle

Question 1

what does it mean by systole

Answer 1

contraction to push blood out of

Question 2

what does it mean by diastole

Answer 2

relation to fill with blood

Question 3

what is atrial systole

Answer 3

atrial walls contract due to high pressure in the atria forcing blood through the atrio ventricular valves into the ventricles which are in diastole

Question 4

what is ventricular systole

Answer 4

ventricles walls contact immediately after atrial systole finishes to force blood through the semi lunar valves into the arteries

Question 5

what is the sinoatrial node

Answer 5

.pacemaker of the heart
.electrical impulses starts here (myogenic because the impulse has not came from a nerve)
.located in the right atrium

Question 6

what is the atrioventricular node

Answer 6

.receives impulses from the SAN
.gives time for the myogenic signal to spread across the atria causing atrial systole
.the AVN then sends signals down to the Bundle of His
.located at the bottom of the night atrium close to the septum

Question 7

what is the Bundle of His

Answer 7

runs down the septum from AVN to the bottom of the ventricles

Question 8

what are the Purkinje fibres

Answer 8

branches off from the Bundle of His into the ventricle walls to cause ventricular systole

Question 9

what does myogenic mean

Answer 9

heart creates own electrical impulses
BUT
the heart rate can be controlled externally by the medulla oblongata in the brain

Question 10

what nerves are active at rest and during exercise

Answer 10

.at rest the vagus nerve is active and tells the SAN to decrease the heart rate
.during exercise the sympathetic nerve is active and tells the SAN to increase the heart rate in order to supply the heart with more blood and o2