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

6008 Views

See similar Biology A Level tutors

Related Biology A Level answers

All answers ▸

Describe how an action potential is generated.


Give two ways in which the presence of synapses are advantageous to the nervous system.


Describe and explain what happens to enzyme activity as the pH is decreased below the optimum pH.


Why is the pancreas both an endocrine and exocrine gland?


We're here to help

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

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences