control of heart rate

Question 1

what occurs in terms of receptors and the nervous system with an increase in heart rate (with exercise)

Answer 1

• chemoreceptors detect rise in CO2
• send impulses to the medulla
• more impulses to the SAN
• by sympathetic (nervous system)

Question 2

how are heart beats coordinated by the SAN

Answer 2

• electrical activity only through AVN
• wave of electrical activity passes over both ventricles at the same time (they both contract at the same time)