Pacemaker potential

Question 1

what occur at phase 4 pf the pacemaker potential

Answer 1

The HCN channels are activated due to hyper polarisation, causing If current to pass through, leading to a slow depolarisation

Question 2

What occurs at phase 0

Answer 2

The L-type calcium channels open, causing influx of calcium and rapid depolarisation

Question 3

what occurs at phase 3

Answer 3

L-type calcium channels shut, potassium channel are activated and open causing efflux of potassium and causing rapid repolarisation

Question 4

what is the top of the pacemaker action potential called?

Answer 4

the overshoot

Question 5

where doe the pacemaker action potential occur

Answer 5

in the SA node

Question 6

what phase determines heart rate?

Answer 6

phase 4

Question 7

what drugs blocks HCN channels, decreasing phase 4 and heart rate?

Answer 7

ivabradine

Question 8

in what way are pacemaker cells unique ?

Answer 8

they can generate action potentials spontaneously without input from the nervous system due to their unstable membrane potentials