User:Eternalsunshine39/sandbox
From Wikipedia, the free encyclopedia
Neurohistology is the study of the microstructure and composition of nervous tissue through the use of various staining methods. In most cases, a Hematoxylin and Eosin (H&E) stain is used to stain the nervous tissue (which makes up the nervous system). There are two nervous systems in our body — the central nervous system (CNS) and the peripheral nervous system (PNS). The PNS further divides into the somatic nervous system and the autonomic nervous system.[1] The microstructure of the nervous tissue within and between both major systems are unique as the CNS consists of the brain and spinal cord, while the PNS consists of all other neurons and neuroglia. A neuron is the basic structural and functional unit of the nervous system. Neurons are specialized to receive chemical stimuli then generate and propagate electrical signals. The functions of a neuron are closely related to the structure of the cell. The neurons are made up of a cell body, axon and dendrites. A cell body contains the nucleus of the neuron and it can be stained using a basophilic dye. The stained portions of the cell body are called nissl bodies. Dendrites are specialized to receive nerve signals from receptors or other relating neurons. Axons are the extensions of the cell body which are involved in transduction of the electrical impulses, i.e. the action potential, along its length. When the neuron is excited, the axon transports neurotransmitters (a chemical messenger) and releases them at synapses (a gap between two neurons).[2][3] A neuron has a long life-span and does not undergo cell division. A sufficient nutritional environment is required for maintaining functional ability throughout life. Additionally, some injured neurons have difficulty recovering after damage. The neuroglia are the surrounding non-neural connective tissues that support the neurons. The CNS has three types of neuroglial cells: astrocytes, oligodendrocytes and microglia. The PNS has one type of neuroglial cell, schwann cells (lemmocytes).