Electrical Activity of Cardiac Muscle Cells

Flashcards summarizing key vocabulary related to the electrical activity of cardiac muscle cells.

SA Node

A collection of pacemaker cells that initiate electrical signals in the heart.

Pacemaker Cell

Specialized cardiac cells that generate rhythmic electrical impulses.

Depolarization

The process by which the membrane potential becomes less negative, leading to an action potential.

Cardiac Muscle Action Potential

An electrical signal crucial for the contraction of cardiac muscle, characterized by rapid depolarization, plateau, and repolarization phases.

Threshold

The level of membrane potential that must be reached for an action potential to occur.

Plateau Phase

A phase in the cardiac action potential where membrane potential remains relatively stable due to calcium influx.

Repolarization

The process by which the membrane potential returns to its resting negative value after depolarization.

Troponin

A protein complex in muscle cells that regulates contraction by allowing interaction between actin and myosin.

Electrocardiogram (ECG)

A recording of the electrical activity of the heart over time, used to assess heart function.

P Wave

Part of the ECG that represents atrial activation.

QRS Wave

Part of the ECG that signifies ventricular activation.

T Wave

The part of the ECG that indicates ventricular relaxation.

Absolute Refractory Period

A period during which a second action potential cannot be initiated, regardless of stimulus strength.

Relative Refractory Period

A period following the absolute refractory period during which a stronger-than-normal stimulus can elicit an action potential.