Word parts
What it means
At rest, the inside of a nerve or muscle cell is negative compared with the outside. When sodium rushes in, the charge flips and the cell fires: a nerve sends a message, or a muscle cell contracts. On an ECG, the P wave shows the atria depolarizing and the QRS complex shows the ventricles depolarizing. The return to the resting state is called repolarization.
At a glance
| Spanish | despolarización |
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Related terms
electrocardiogram
A test that records the heart's electrical activity as waves on paper or a screen.
sodium
A mineral in the blood that controls how water moves in the body and helps nerves and muscles work.
conduction
The passing of something, such as an electrical signal or heat, from one place to another through a material.
neuron
A nerve cell: a cell that carries electrical and chemical signals through the nervous system.
cardiac cycle
The series of events in one heartbeat, from the start of one beat to the start of the next.