Nerve cells
Nerve cells are also called Nerve cells. They carry an electrical message or impulse when stimulated.. They are adapted to carry electrical impulses from one place to another. They feature:
- an The long part of a nerve cell along which the electrical signal quickly moves. 鈥 a single nerve fibre that carries nerve impulses away from a cell body which is insulated by a fatty sheath
- Small extensions found on the end of dendrons that connect one neuron to another. - branched nerve fibres which receive nerve impulses and pass them towards a cell body.
The axon is insulated by a fatty (A substance made from protein and lipids (fat) that surrounds the axon of a nerve cell. The myelin sheath insulates the axon and increases the rate at which electrical signals travel through the nerve.) sheath. The fatty sheath increases the speed of the nerve impulses along the neuron.
Myelination is the process of myelin developing around the axon fibres. It continues from birth to adolescence.
Certain diseases, such as A condition, usually autoimmune, in which the myelin sheaths of the neurones of the brain and spinal cord are damaged, reducing the transmission of nerve impulses, and leading eventually to paralysis. and Poliomyelitis (polio) is a highly infectious viral disease which mainly affects young children. The disease causes paralysis, which is often permanent., cause the myelin sheath to be destroyed. This causes damage to motor neurons which means that muscles no longer receive signals from the brain or spinal cord. This results in loss of strength and co-ordination in the limbs.
Myelin sheath is produced by glial cells. Glial cells do not transmit nerve impulses. Instead they maintain The body maintaining a constant internal environment for the proper functioning of cells and enzymes., form myelin, and provide support and protection for neurons. Glial cells also remove any debris by The process of the ingestion of bacteria or other material by phagocytes..