the cardiovascular system

Question 1

sinoatrial node (SAN)

Answer 1

• known as the hearts ‘pacemaker’
• sends an impulse to the right atrium causing muscular walls to contract
• the contraction forces blood from the atrium to the ventricles

Question 2

atrioventricular node (AVN)

Answer 2

• located between atria and ventricles
• acts as a buffer that slows signal from SAN (or else atria and ventricles contract at same time)
• this allows ventricles to fill with blood before contraction

Question 3

bundle of his

Answer 3

• located in the septum, separates ventricles
• branches into two bundles
• specialist heart muscle cells that are responsible for transporting the electrical impulses from the AVN

Question 4

purkinje fibres

Answer 4

• located in walls of ventricles
• carry the impulse to ventricle walls, causing them to contract at paced intervals
• contraction causes blood within ventricles to be pushed up and out of the heart, either to lungs or working muscles

Question 5

effects of the sympathetic nervous system

Answer 5

during exercise it causes heart rate to increase

Question 6

effects of the parasympathetic nervous system

Answer 6

after exercise, it returns your heart rate back to resting levels