Describe how the rhythmicity of the heart is established and maintained with respect to the different stages in the cardiac cycle (6 marks)

The Sinoatrial Node (SAN) generates the wave of excitation/ Action potential (AP).

The AP spreads across the atrial walls, stimulating the myocardial cells to contract This initiates the atrial systole.

The AP is then transmitted to the Atrioventricular Node (AVN).

Here it is delayed.

Once Atrial systole has finished the AP is conducted down the purkinje fibres/ bundle of His.

when it reaches the apex/base of the Heart it spreads across the ventricular walls.

This stimulates the myocardial cells in this region to contract.

This initiates the ventricular systole.

HM
Answered by Haider M. Biology tutor

6234 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

How can a child have cystic fibrosis when neither of the parents have the disorder? (5 Marks)


What are the features of ATP which lead it to being termed the 'universal currency' of the cell?


Outline how a heartbeat is initiated and controlled


Explain the difference between tidal volume and total vital capacity. Under what circumstances would each occur?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning