Podcast
Questions and Answers
What triggers the next impulse in rhythmically discharging cells?
What triggers the next impulse in rhythmically discharging cells?
- IK bringing about repolarization
- Prepotential or pacemaker potential (correct)
- Activation of the 'h' channel
- Membrane potential reaching a hyperpolarized level
What type of channels opens at the peak of each impulse to bring about repolarization?
What type of channels opens at the peak of each impulse to bring about repolarization?
- 'F' channel
- H channels (correct)
- T channels
- L channels
What is another name for the channel activated following hyperpolarization due to its unusual activation?
What is another name for the channel activated following hyperpolarization due to its unusual activation?
- 'L' channel
- 'Ih' channel
- 'T' channel
- 'Funny' channel (correct)
What completes the prepotential in rhythmically discharging cells by producing the calcium current?
What completes the prepotential in rhythmically discharging cells by producing the calcium current?
Which part of the cell membrane begins to depolarize as Ih increases, forming the first part of the prepotential?
Which part of the cell membrane begins to depolarize as Ih increases, forming the first part of the prepotential?
Which part of the heart's conduction system lacks a sharp, rapid depolarizing spike before the plateau in its action potentials?
Which part of the heart's conduction system lacks a sharp, rapid depolarizing spike before the plateau in its action potentials?
What happens to the slope of prepotentials in nodal tissue when cholinergic vagal fibers are stimulated?
What happens to the slope of prepotentials in nodal tissue when cholinergic vagal fibers are stimulated?
How does acetylcholine affect the membrane of nodal tissue?
How does acetylcholine affect the membrane of nodal tissue?
What is the mechanism through which M2 muscarinic receptors affect the nodal tissue?
What is the mechanism through which M2 muscarinic receptors affect the nodal tissue?
What effect does strong vagal stimulation have on the rate of spontaneous discharge?
What effect does strong vagal stimulation have on the rate of spontaneous discharge?
How does norepinephrine, secreted by sympathetic endings, affect the L channels in nodal tissue?
How does norepinephrine, secreted by sympathetic endings, affect the L channels in nodal tissue?
What is the role of the sympathetic cardiac nerves in speeding up the rate of spontaneous discharge?
What is the role of the sympathetic cardiac nerves in speeding up the rate of spontaneous discharge?
