Action Potential Heart

A and C show

• SA node and Bundle of His

• Bundle of His and Purkinje fibres

• SA node and AV node

Which of the following is correct regarding intracellular calcium concentration?

• Ca2+ falls to allow cardiomyocyte contraction during systole

• Ca2+ rises to allow cardiomyocyte contraction during diastole

• Ca2+ rises to allow cardiomyocyte contraction during systole

• Ca2+ rises to allow cardiomyocyte relaxation during systole

B and D show

• SA node and AV node

• AV node and Purkinje fibres

• Purkinje fibres and Bundle of His

• SA node and Bundle of HIs

Which one of the following statements is correct ?

• Noradrenaline speeds-up heart rate by making the pacemaker potential steeper

• Acetylcholine speeds-up the heart rate by making the pacemaker potential shallower

• Noradrenaline speeds-up heart rate by making the pacemaker potential shallower

• Acetylcholine slows heart rate by making the pacemaker potential steeper

Tags

NGSS.HS-LS1-3

Which is correct regarding the resting membrane potential

• Na+ concentration is higher outside the cell

• K+ concentration is higher outside the cell

• Na+ concentration is lower outside the cell