Depolarization

Definition

Depolarization is the process by which the resting membrane potential of a cell becomes less negative. It is a critical event in the conduction of electrical impulses within the cardiovascular system.

5 Must Know Facts For Your Next Test

1. Depolarization initiates the contraction of cardiac muscle cells and is essential for maintaining effective heart rhythms.
2. During depolarization, sodium (Na+) ions rapidly enter the cardiac cells, causing a change in electrical charge.
3. The sinoatrial (SA) node is responsible for initiating depolarization in the heart's conduction system.
4. Depolarization precedes repolarization, which returns the cell to its resting state.
5. Abnormalities in depolarization can lead to arrhythmias or irregular heartbeats, which are critical concerns in pharmacology.

Review Questions

• What ion primarily enters cardiac cells during depolarization?
• Which part of the heart's conduction system initiates depolarization?
• Why is proper depolarization important for cardiovascular function?

Related terms

Sinoatrial Node (SA Node): The natural pacemaker of the heart that initiates depolarization.

Repolarization:

The process by which a cell's membrane potential returns to its resting state after depolarization.

Arrhythmia:

An irregular heartbeat that can result from abnormalities in depolarization.