Podcast
Questions and Answers
What is the term used to describe the time period during which a cell is unexcitable to stimulation?
What is the term used to describe the time period during which a cell is unexcitable to stimulation?
- Absolute refractory period (correct)
- Relative refractory period
- Supranormal period
- Effective refractory period
Which type of fibers can spontaneously generate action potentials without neural input?
Which type of fibers can spontaneously generate action potentials without neural input?
- Atrial fibers
- SA Node fibers (correct)
- Purkinje fibers
- Ventricular fibers
What is a key difference between the resting membrane potential of the SA Node and the Atrial, Ventricular, and Purkinje fibers?
What is a key difference between the resting membrane potential of the SA Node and the Atrial, Ventricular, and Purkinje fibers?
- Stable resting membrane potential
- Unstable resting membrane potential (correct)
- Long duration of action potential
- Sustained plateau
During which period does stimulation produce a weak action potential that propagates more slowly than usual?
During which period does stimulation produce a weak action potential that propagates more slowly than usual?
Which type of stimulus can trigger an action potential during the supranormal period?
Which type of stimulus can trigger an action potential during the supranormal period?
What distinguishes the ERP (effective refractory period) from the ARP (absolute refractory period)?
What distinguishes the ERP (effective refractory period) from the ARP (absolute refractory period)?
Which phase of the cardiac action potential is characterized by the movement of the membrane potential towards the resting potential?
Which phase of the cardiac action potential is characterized by the movement of the membrane potential towards the resting potential?
Which type of potassium current is responsible for maintaining the resting membrane potential?
Which type of potassium current is responsible for maintaining the resting membrane potential?
What is the primary difference between the delayed rectifier potassium currents I$_Ks$ and I$_Kr$?
What is the primary difference between the delayed rectifier potassium currents I$_Ks$ and I$_Kr$?
What is the primary ionic mechanism responsible for the repolarization phase (phase 3) of the ventricular action potential?
What is the primary ionic mechanism responsible for the repolarization phase (phase 3) of the ventricular action potential?
Which phase of the cardiac action potential is characterized by a stable membrane potential?
Which phase of the cardiac action potential is characterized by a stable membrane potential?
Which phase of the SA node action potential is characterized by repolarization?
Which phase of the SA node action potential is characterized by repolarization?
Which type of potassium current is responsible for the transient outward phase (phase 1) of the cardiac action potential?
Which type of potassium current is responsible for the transient outward phase (phase 1) of the cardiac action potential?
What ion current contributes to the slow depolarization in Phase 4 of the SA node action potential?
What ion current contributes to the slow depolarization in Phase 4 of the SA node action potential?
Which phase of the SA node action potential accounts for the automaticity of SA node cells?
Which phase of the SA node action potential accounts for the automaticity of SA node cells?
What sets the heart rate in relation to the SA node action potential?
What sets the heart rate in relation to the SA node action potential?
What is the most negative value of the membrane potential in the SA node action potential?
What is the most negative value of the membrane potential in the SA node action potential?
In the SA node action potential, what brings the membrane potential to threshold for Ca2+ channels to open?
In the SA node action potential, what brings the membrane potential to threshold for Ca2+ channels to open?
