controlling heart rate

Question 1

what part of the brain controls heart rate

Answer 1

cardiovascular control centre in the medulla oblongata

Question 2

what nerves are involved in regulating heart rate

Answer 2

nerves of the autonomic nervous system transmit impulses from the cardiovascular centre to the heart

Question 3

role of the sympathetic nerve

Answer 3

transmits impulses to the SAN which leads to an increase in cardiac output

Question 4

role of the parasympathetic nerve

Answer 4

transmits impulses to the SAN and AVN which leads to a decrease in cardiac output

Question 5

sequence events leading to an increase in heart rate

Answer 5

1. chemoreceptors of the medulla detects more acidic blood or high levels of CO2
2. cardiovascular control centre of the medulla sends impulses along the sympathetic nerve to SAN
3. SA node responds by sending out more frequent impulses resulting in an increased heart rate

Question 6

impact of adrenaline

Answer 6

• adrenaline is released in response to fear or stress and is carried in the blood to the SAN, this increases the rate of impulses from the SAN making the heart rate increase
• adrenaline also causes more blood to be sent to the skeletal muscles causing vascular shunting by vasodilating arterioles while also constricting arterioles going to non-essential organs so there os more blood available for important organs so the body is more prepared for fight or flight.