lecture 11: initiation and regulation of heart beat

Question 1

what triggers cardiac action potential depolarisation

Answer 1

rapid influx of sodium ions

Question 2

what causes plateau of cardiac action potential

Answer 2

opening of slow voltage ghated calcium channels and closing of some potassium channels. net voltage change is zero but ions are still moving across

Question 3

what causes repolarisation in cardiac muscle cell

Answer 3

opening of potassium channels and closing of calcium channels

Question 4

pacemaker cell function

Answer 4

to initiate cardiac action potential. contained in SA node and AV node

Question 5

ECG P wave

Answer 5

caused by SA node and atrial muscle action potential depolarisation

Question 6

ECQ QRS complex

Answer 6

caused by action potential in common bundle, bundle branckes, purkinje fibres, ventricular muscle

Question 7

ECG T wave

Answer 7

caused by cell repolarisation in heart

Question 8

ECG P-Q interval

Answer 8

AV node causing delay

Question 9

ECG S-T interval

Answer 9

plateau phase in cardiac action potential