nervestrukturen

Nervestrukturen refers to the structural organization of nerves within the nervous system. The nervous system is commonly divided into the central nervous system (CNS), consisting of the brain and spinal cord, and the peripheral nervous system (PNS), which comprises nerves and ganglia that connect the CNS to the rest of the body. The basic functional units are neurons, which transmit electrical signals, and glial cells, which provide support and insulation.

A typical neuron has a cell body, dendrites that receive signals, and an axon that conducts impulses to other cells. In the PNS, many axons are insulated by a myelin sheath produced by Schwann cells, while in the CNS myelin is formed by oligodendrocytes. The gaps between myelin segments, called nodes of Ranvier, facilitate rapid saltatory conduction. Neurons communicate at synapses through neurotransmitters.

Nerve fibers are organized into bundles surrounded by connective tissue layers. The innermost layer, the endoneurium, encloses individual fibers; several fibers form a fascicle wrapped by the perineurium; and the whole nerve is encased by the epineurium. In the body, nerves may form networks called plexuses, such as the brachial or lumbosacral plexus, to distribute signals to target regions. The blood supply to nerves supports their metabolic needs and function.

Developmentally, the PNS largely originates from neural crest cells, whereas the CNS derives from the neural tube. Functionally, nervestrukturen enable sensation, motor control, reflexes, and autonomic regulation. Injury or disease can affect axons, myelin, or synapses, leading to neuropathies, radiculopathies, or demyelinating conditions.