Assignment on Nervous system

Topics: Nervous system, Neuron, Axon Pages: 9 (1364 words) Published: January 11, 2015
Nervous System
Differences according to:
Motor neurons
Sensory neurons
Autonomic neurons
Function
Transmits impulses from the CNS which consists of the brain and spinal cord to muscles and glands elsewhere in the body Transmits impulses inwards from the sense organs to the CNS
Located within the CNS, they transmit the electrical impulses generated by the stimuli to other nerves Structure
Have Dendrites, Cell Body, Myelin Sheath, Node of Ranvier and Synaptic Knobs. The cell body is located at the top Don’t have Dendrites, but have Cell Body, Myelin Sheath, Node of Ranvier and Synaptic Knobs. The cell body is located close to the middle region

Don’t have Dendrites, Myelin Sheath, or Node of Ranvier but have Cell Body and Synaptic Knobs. The cell body is located at the middle.

The nervous system is a complex network of nerves and cells that carry messages to and from the brain and spinal cord to various parts of the body. The nervous system includes both the Central nervous system and Peripheral nervous system. The Central nervous system is made up of the brain and spinal cord and The Peripheral nervous system is made up of the Somatic and the Autonomic nervous systems.

The Central nervous system
The central nervous system is divided into two major parts: the brain and the spinal cord. The brain
The brain lies within the skull and is shaped like a mushroom.  The brain consists of four principal parts: the brain stem
the cerebrum
the cerebellum
the diencephalon
There are two types of matter in the brain:  grey matter and white matter.  Grey matter receives and stores impulses.  Cell bodies of neurons and neuroglia are in the grey matter.  White matter in the brain carries impulses to and from grey matter.  It consists of the nerve fibers (axons). The brain stem

The brain stem is also known as the Medulla oblongata. It is located between the pons and the spinal cord and is only about one inch long. The cerebrum
The cerebrum forms the bulk of the brain and is supported on the brain stem.  The cerebrum is divided into two hemispheres.  Each hemisphere controls the activities of the side of the body opposite that hemisphere.  The hemispheres are further divided into four lobes:

Frontal lobe
Temporal lobes
Parietal lobe
Occipital lobe
The cerebellum
This is located behind and below the cerebrum. 
The diencephalon
The diencephalon is also known as the fore brain stem. It includes the thalamus and hypothalamus. The thalamus is where sensory and other impulses go and coalesce. The hypothalamus is a smaller part of the diencephalon

The spinal cord
The spinal cord is along tube like structure which extends from the brain. The spinal cord is composed of a series of 31 segments.  A pair of spinal nerves comes out of each segment.  The region of the spinal cord from which a pair of spinal nerves originates is called the spinal segment.  Both motor and sensory nerves are located in the spinal cord. The spinal cord is about 43 cm long in adult women and 45 cm long in adult men and weighs about 35-40 grams. It lies within the vertebral column, the collection of bones (back bone). Other parts of the central nervous system

The meninges are three layers or membranes that cover the brain and the spinal cord.  The outermost layer is the dura mater.  The middle layer is the arachnoid, and the innermost layer is the pia mater. The meninges offer protection to the brain and the spinal cord by acting as a barrier against bacteria and other microorganisms. The Cerebrospinal Fluid (CSF) circulates around the brain and spinal cord. It protects and nourishes the brain and spinal cord.

Neurons
The neuron is the basic unit in the nervous system. It is a specialized conductor cell that receives and transmits electrochemical nerve impulses. A typical neuron has a cell body and long arms that conduct impulses from one body part to...
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