Parts of the Nervous System.

The nervous system is made us of three different system sections. First is the Central Nervous System, or CNS. The CNS is central to the bodys systems and workings, and is composed of the brain and its chrif nerve, the spinal cord which runs along the inside of the backbone (vertibral or spinal column). Fron the CNS branches off 43 different nerve pairs 12 of which run form the brain and 31 from the spinal cord. As the pairs divide, they snake along among tissue and organs. Form here they part and form the PNS or peripheral nervous system. In the nervous system the CNS is the coordinator and decision maker. The PNS sends niformation as sensatory input and recieves instructions as output to glands and muscles. The third and last component that makes up the nervous systen is the ANS or autonomic nervous system which has some elements located in the CNS and also shares some nerves with hte PNS. The autonomic nervous system aslo has its own seperate nerve chains which run alongside the spinal cord. Is work is mosty 'automatic' meaning it deals with activities such as blood pressure and heart rate adjustment which are things we are rarely aware of.

Nerves and Neurons.

A typical neuron has a amin cell body that includes a nucleus, but a aneuron also has a wire like process that reache sout to transmit messages th other neurons which happens at junctions called Synapses. This process has two main kinds, Dendrites, which recieve messages from other neurons or nerve like cells in sense organs and conduct towards the cell body of a neuron. The other types are called Axons which convey messages away form the cell body of a neuron. Axons are longer and usually branch less than Dendrites which are shorter and branch out more aklong their length. To conclude, Neurons that are in the brain and spinal cord are protecetd and nurtured or fed by supporting cells called Glail Cells.

Neurotransmitters.

In addition, the most important part in understanding the nervous systems workings is the Neurotransmitters. When electrical impulses arrive at the body's synapses, they trigger the release of different chemicals. The Neurotransmitters cross the Synaptic Cleft which is an incredibly thin gap, between Presynaptic membranes which send the chemicals , and Postsynaptic or recieving neurons. With the chemicals there now is either a new impulse in the neuron that recieves (postsynaptic) or the chemicals will inhibit the neuron form firing more chemicals.