Cardiac muscle and the heartbeat

Question 1

myogenic

Answer 1

contracts without an external stimulus

Question 2

intrinsic rhythmicity

Answer 2

the intrinsic (internal) rhythm of contraction and relaxation in the cardiac muscle of the heart

Question 3

sinoatrial node (SAN)

Answer 3

a specialised group of cells in the right atrium with the fastest natural intrinsic rhythm; it generates a regular electrical signal and acts as the heart’s own natural pacemaker to keep the heart beating regularly

Question 4

atrioventricular node (AVN)

Answer 4

a group of cells stimulated by the wave of excitation from the SAN and the atria; it imposes a delay before transmitting the impulse to the bundle of His

Question 5

bundle His

Answer 5

a group of conducting fibres in the septum of the heart

Question 6

Purkyne tissue

Answer 6

conducting fibres that penetrate down through the septum of the heart, spreading between and around the ventricles

Question 7

electrocardiogram (ECG)

Answer 7

technology used to investigate the rhythms of the heart by producing a record of the electrical activity of the heart