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WorksheetsQuiz on Pacemaker Cells and Intrinsic Conduction System
Total questions: 15
Worksheet time: 8mins
What is the initial event in the pacemaker potential?
Opening of voltage-gated calcium channels
Opening of cation leak channels
Closing of potassium channels
Opening of sodium channels
What happens at the threshold of pacemaker cells?
Voltage-gated potassium channels open
Voltage-gated calcium channels open
Cation leak channels close
Membrane potential becomes negative
What is the role of voltage-gated calcium channels in pacemaker cells?
They maintain resting potential
They close cation leak channels
They cause repolarization
They cause depolarization
What triggers the opening of voltage-gated potassium channels?
Closing of calcium channels
Hyperpolarization of the cell
Opening of sodium channels
Reaching the threshold potential
What is the result of potassium flowing out of the cell?
Threshold potential is reached
Hyperpolarization of the cell
Repolarization of the cell
Depolarization of the cell
What happens after the efflux of potassium in pacemaker cells?
The cell becomes hyperpolarized
The cell becomes depolarized
The voltage-gated calcium channels open
The cation leakage channels reopen
What is the function of the sinoatrial (SA) node?
To delay the impulse
To generate impulses
To contract the ventricles
To open calcium channels
What occurs during atrial muscle depolarization?
The ventricles contract
The AV node generates impulses
The SA node delays the impulse
The atria contract
What is the role of the intrinsic conduction system?
To close cation leak channels
To ensure the heart beats as a functional syncytium
To delay impulses at the SA node
To open potassium channels
What is the critical delay at the atrioventricular (AV) node for?
To allow ventricular filling
To allow atrial contraction
To allow atrial filling
To allow ventricular contraction
What happens during rapid conduction to the ventricular apex?
The atria contract
The ventricles contract
The impulse is delayed
The SA node generates impulses
What is the direction of ventricular contraction?
From right to left
From left to right
From apex to base
From base to apex
What ensures the heart beats as a single contractile unit?
The hyperpolarization of cells
The closing of potassium channels
The intrinsic conduction system
The opening of calcium channels
What is the effect of hyperpolarization in pacemaker cells?
It briefly continues the efflux of potassium
It closes cation leak channels
It opens voltage-gated calcium channels
It depolarizes the cell
What happens when cation leakage channels reopen?
The cell depolarizes
The cell repolarizes
The threshold potential is reached
The pacemaker potential is restored
