What is the Nervous System I ?? A brief info.



Okay, so let’s talk about the nervous system. The nervous system has two major divisions, the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain, spinal cord, optic nerve, and retina. Whereas the peripheral nervous system consists of the nerves like the cranial and the spinal.

Furthermore,  the peripheral nervous system consists of the autonomic nervous system and the special senses, and the autonomic nervous system can be further divided into the sympathetic and parasympathetic nervous systems.

Apart from them, the gut has its own brain the enteric nerves which can handle the local activity of the gut. 

In the CNS, the cell bodies of neurons are often grouped together in discrete areas termed nuclei. The cell bodies of various neurons form the layers and they collectively form the grey matter and the collection of the axons is called the white matter because they are coated with myelin sheaths and it appears white when fresh.

The neurons have axons that carry signals and these are bundled near the cell bodies and are called the tracts and these tracts send different types of signals or functions to the grey matter where we can interpret the signals.

Let's shortly talk about the PNS and its functions


PNS efferents are the axons of spinal cord motor neurons that carry motor-movement signals out of the spine to the muscles. In the CNS, afferent and efferent projections are determined from the perspective of any given brain region. Mostly they bring information.


The composition of the PNS is as follows-


Efferent fibers of the motor neurons inside the CNS


The cell bodies of the sensory neurons that are grouped together as ganglia


Ganglionic Neurons of the ANS which relive contract from the peripheral fibers of the preganglionic autonomic neurons whose cell bodies lie within the CNS
.



Now, let's talk about the spinal cord. In the form of an embryo, the neural tube thickness and forms the spinal cord but it does not obliterate the cavity that is in the tube and that later expands and forms the central canal in the Spinal column and a ventricular system in the brain which contains the CSF,

The CSF is secreted by, CHOROID PLEXUS which is formed by the roof of the neural tube.

The roof of the neural fluke does not form any neurons but the choroid plexus

CSF - It is basically the interstitial fluid of the brain which is present in the central canal, the ventricles, the subarachnoid space.

The brain has a very high supply of blood & it is regulated and restricted

The restriction is caused by the BBB (blood-brain-barrier) which keeps the blood away from the neuropil.

Now, let's talk about the transmission of the nerve signals. How are they transmitted throughout the body? In short there. different kinds of synapses that are happening throughout the body which help in the relay of the information.
a) The electrical Synapse

b) The neurotransmitter synapse which requires the release of a neuro Transistor

These transmissions occur Through a series of events -

action potential, the repolarization, and depolarisation of neurons occur and That's how a neural transmission travels.

OTHER CELLS of THE NERVOUS SYSTEM

Apart from the neurons and the blood vessels, there are other cells present in the nervous System

A. glial cells- These cells do not generate action potentials, but convey information encoded as transient changes in intracellular calcium concentration, termed calcium signaling. they interact with neurons in many different ways; their two-way communication is essential for normal brain activity.

B.Other cells -The glial population in the CNS consists of microglia and macroglia; the latter is subdivided into oligodendrocytes and astrocytes. The principal glial cell in the PNS is the Schwann cell. Satellite cells surround each neuronal soma in the ganglia.

This was, a brief intro about the nervous system and what it consist of more info on the next one. !!!

Till then stay healthy, safe, and informed







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