The Nervous System is a complicated system that is the primary form of communication between cells and organs throughout the body.

This communication allows for such actions as: muscle contraction, thoughts to proceed, actions to be made, and others.

The nervous system is divided into 2 categories:

1.)  Peripheral Nervous System
2.)  Central Nervous System

Peripheral nervous system (PNS)

–  The PNS is located distinctly outside the Central nervous system.
–  The Central nervous system consists of the brain and spinal cords.
–  The function of the PNS is to allow the central nervous system to connect with the limbs and organs.

Central Nervous System

–  The CNS is found within the meninges of the brain.
–  The main function of the CNS is the reception of information, the processing of that information, and often the decision or reaction made to the information.
–  The CNS is quite complex and the location is extensive

Spinal Cord

–  The spinal cord is protected by bone of the vertebral column.
–  The function of spinal cord is the conduction of impulses from the brain to the peripheral nervous system to extremities and back again.
–  There are 31 segments of the spinal cord.
–  The complexity of the nervous system is often regulated by signals and neurotransmitters that transmit from one neuron to another.
  –  Neurons are a main component of the nervous system.


Neurons

–  These are the cells that react and act in the process of receiving and transmitting information by signaling.
–  They are an important function of the nervous system.
–  Neurons themselves can differ greatly – some allow for touch, visual, light, smell, sound and many others. 
–  Neurons in limbs receive stimuli and transfer or send the signal to the spinal cord and to the brain.

Within the nervous system are several cells with complex responsibilities:

1.)  Microglia

–  Are specialized cells of the Nervous system
–  Act as macrophages
–  Can protect neurons
–  Found in brain and spinal cord
–  Are mobile

2.)  Astrocytes

–  Are apart of the CNS system
–  Are shaped in a pattern of a star
–  Helps maintain the cells of the blood-brain barrier
–  Helps remedy any injury to the brain
–  Has a role in scar formation

3.)  Ependymal

–  Are apart of the CNS system
–  Cells that line the brain and spinal cords
–  Helps produce cerebrospinal fluid (CSF)

4.)  Oligodendroglia

–  Are an aspect of the CNS system
–  Similar to Schwann cells of the PNS
–  Wraps around the axon
–  Forms the myelin sheath
–  Can wrap around 40-50 axons

5.)  Schwann

–  Are apart of the PNS
–  Similar to Oligodendroglia of the CNS
–  Wraps around the axon
–  Forms the myelin sheath
–  Can wrap around only 1 axon
–  Permits Nodes of Ranvier

6.)  Satellite

–  Are apart of the PNS
–  Are linear schwann cells
–  Believed to be similar to Astrocytes in CNS
–  Supply nutrients to cells

VN:F [1.9.22_1171]
Rating: 5.5/10 (2 votes cast)
VN:F [1.9.22_1171]
Rating: +3 (from 3 votes)
Nervous System, 5.5 out of 10 based on 2 ratings