Function and Structure of Axons: Key to Neurological Disorders Research

Axons

Transmit nerve impulses.

Axons are long, slender, and tubular extensions of nerve cells that transmit signals or impulses away from the neuron’s cell body to other cells, including neurons and muscle cells. Axons are a vital component of the nervous system, enabling the rapid transmission of electrical signals throughout the body.

Axons have a specialized structure consisting of a cell membrane, cytoplasm, and a network of microtubules and microfilaments. The axon membrane is polarized, meaning that it has different electrical charges on either side. This polarization is maintained by sodium-potassium pumps that actively transport ions across the membrane.

Axons are covered by a white, fatty substance called myelin, which is produced by specialized support cells in the nervous system called oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system. Myelin serves as an insulator, allowing signals to travel faster and with less energy loss than unmyelinated axons.

Axons can vary in length from a few millimeters to over a meter. The longest axon in the human body belongs to the sciatic nerve, which is over a meter long and runs from the lower back to the foot.

Axons transmit signals in a process called action potential. When a signal reaches the axon, it triggers the opening of ion channels in the membrane, allowing positively charged ions to flow into the cell, which depolarizes the membrane. This depolarization generates an electrical impulse that travels along the axon, activating more ion channels and causing a chain reaction, resulting in the release of neurotransmitters at the axon terminal.

In neurodegenerative diseases such as multiple sclerosis and amyotrophic lateral sclerosis, the myelin or the axon itself can be damaged, leading to impaired signal transmission and loss of function. Researchers are actively studying axons and their mechanisms to develop new treatments and therapies for these and other neurological disorders.

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