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.

Answered by Haider M. Biology tutor

5526 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe the process of transcription


Briefly describe the environmental effects of nitrogen fertilisers in a body of water


What is negative feedback and what is positive feedback? Give an example for each of where it is important in regulation?


Describe the role of a ribosome in the production of a polypeptide.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo
Cookie Preferences