The Pacemaker Potential EXPLAINED

The video explains the cardiac pacemaker potential, focusing on the sinoatrial node as the heart's pacemaker. It details the role of voltage-gated sodium, calcium, and potassium channels in generating action potentials. The heart's auto rhythmic nature is highlighted, emphasizing that it doesn't require nervous system input to beat. However, the nervous system can modulate heart rate by altering the pacemaker potential. The video concludes with a preview of the next topic: the biochemical steps of heart muscle contraction.

What is the primary role of the sinoatrial node in the heart?

• To act as the heart's pacemaker

• To pump blood throughout the body

• To filter blood impurities

• To regulate blood pressure

Which ion channel opens automatically at a membrane potential of -60 mV in pacemaker cells?

• Calcium channel

• Chloride channel

• Sodium channel

• Potassium channel

What happens when calcium enters the pacemaker cell during depolarization?

• The cell stops functioning

• The cell becomes more negative

• The cell becomes more positive

• The cell remains unchanged

Why is the membrane potential of pacemaker cells considered unstable?

• Because it is always at rest

• Because it is constantly depolarized

• Because it requires external stimuli to function

• Because it never reaches a resting state

What is the consequence if pacemaker cells come to rest?

• The heart beats irregularly

• The heart stops beating

• The heart rate decreases

• The heart rate increases

How does the parasympathetic nervous system affect heart rate?

• It increases the heart rate

• It decreases the heart rate

• It has no effect on heart rate

• It causes the heart to stop

What effect does epinephrine have on the pacemaker potential?

• It stops depolarization

• It has no effect on depolarization

• It increases the rate of depolarization

• It decreases the rate of depolarization