Axons: Definition & Function

Communication via Axons

At rest, the membrane potential of an axon is typically -70 millivolts. This charge is established by ATP-driven pumps in the membrane known as sodium/potassium pumps. This pump ensures that more positive ions are outside of the membrane compared to inside of the cell. When the neuron depolarizes, or becomes positively charged, it will transmit this communication down the axon by way of voltage-gated, which means electrically controlled, ion channels that open up to allow for the charge to relay along the axon. This takes place until the charge reaches for the axon terminal.

The axon terminal is the site of neurotransmitter release. Neurotransmitters are chemical messengers that are released from the axon and received by effector cells. This process is critical for delivery of the message to the cells and tissues that are being controlled. The terminal, then, is the final point of stimulation in the axon before the charge is delivered.

Lesson Summary

The axon is an extended region of the neuron cell membrane and the portion of the cell responsible for delivering cell-to-cell communication. Neurons are the cells that communicate and the axons are merely a smaller part of the larger story. This is sometimes sped up by myelin sheaths, which are a type of insulation that speeds up the transmission of cell-to-cell communication and stimulation. Through transmission of electrical charges and the release of neurotransmitters, axons are able to control target cells in order to regulate bodily processes. Beginning at the axon hillock, this process is completed through the movement of ions. Ion concentration will establish the resting membrane potential, which is the electrochemical charge of the membrane when the neuron is at rest and is approximately -70 millivolts. Axons are the key components of neuronal function for the nervous system and other systems under nervous control.