Neural Control of Cardiac Cycle

Question 1

Sinoatrial Node (SAN)

Answer 1

• Located within the walls of the right atrium
• Sends signal from right atrium through the walls of the atria which causes muscular walls to contract
• Contraction forces the blood within the atria down into the ventricles

Question 2

Atrioventricular Node (AVN)

Answer 2

• Located between atria and ventricles (centre)
• Acts as a buffer or gate that slows down signal from SAN
• By slowing down signal, atria can contract before ventricles meaning ventricles are relaxed and open for blood from atria at top of heart

Question 3

Bundle of His

Answer 3

• Specialist heart muscle cells responsible for transporting the electrical impulses from AVN
• Found in walls of ventricles and septum

Question 4

Pirkinje Fibres

Answer 4

• Found at end of Bundle of His
• Allow ventricle to contract at regular intervals
• Causes blood to be pushed out of heart to either lungs or working muscles