Excitable Cells and Resting Membrane Potential

What is an excitable cell?

A cell whose membrane can hold an electrical charge and propagate signals.

What are the two main types of excitable cells?

Neurons and muscle cells.

What happens when neurons are excited?

They transmit electrical impulses.

What happens when muscle cells are excited?

They contract and produce force.

What is resting membrane potential (RMP)?

The electrical potential difference across a cell's plasma membrane at rest.

What is the normal resting membrane potential of a neuron?

Approximately −70 mV.

What is the normal resting membrane potential of a muscle cell?

Approximately −85 mV.

What does a negative resting membrane potential mean?

The inside of the cell is negatively charged relative to the outside.

What units are used to measure membrane potential?

Millivolts (mV).

Do excitable cells have a membrane potential of zero when resting?

No, all maintain a nonzero resting membrane potential.

What does an action potential graph show?

The change in membrane potential (mV) over time (ms).

What is the threshold potential for an action potential in a typical neuron?

Approximately −55 mV.