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Nervous tissue, also called neural tissue, is the main tissue component of the nervous system.The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves.
Heart rate is largely controlled by the heart's internal pacemaker activity. Considering a healthy heart, the main pacemaker is a collection of cells on the border of the atria and vena cava called the sinoatrial node. Heart cells have the ability to generate electrical activity independent of external stimulation.
Schwann cells or neurolemmocytes (named after German physiologist Theodor Schwann) are the principal glia of the peripheral nervous system (PNS). Glial cells function to support neurons and in the PNS, also include satellite cells, olfactory ensheathing cells, enteric glia and glia that reside at sensory nerve endings, such as the Pacinian corpuscle.
Similar in function to oligodendrocytes, Schwann cells provide myelination to axons in the peripheral nervous system (PNS). They also have phagocytotic activity and clear cellular debris that allows for regrowth of PNS neurons. [18] PNS: Satellite cells: Satellite glial cells are small cells that surround neurons in sensory, sympathetic, and ...
Satellite glial cells are a type of glia found in the peripheral nervous system, specifically in sensory, [2] sympathetic, and parasympathetic ganglia. [3] They compose the thin cellular sheaths that surround the individual neurons in these ganglia. In a SGC, the cell body is denoted by the region containing the single, relatively large nucleus ...
The PNS includes motor neurons, mediating voluntary movement; the autonomic nervous system, comprising the sympathetic nervous system and the parasympathetic nervous system and regulating involuntary functions; and the enteric nervous system, a semi-independent part of the nervous system whose function is to control the gastrointestinal system.
Astrocytes detect neuronal activity and can release chemical transmitters, which in turn control synaptic activity. [ 51 ] [ 57 ] [ 58 ] In the past, hyperalgesia was thought to be modulated by the release of substance P and excitatory amino acids (EAA), such as glutamate , from the presynaptic afferent nerve terminals in the spinal cord dorsal ...
Diseases of the peripheral nervous system can be specific to one or more nerves, or affect the system as a whole. Any peripheral nerve or nerve root can be damaged, called a mononeuropathy. Such injuries can be because of injury or trauma, or compression. Compression of nerves can occur because of a tumour mass or injury.