Histology Research

Entitled

Nuervous cells

By

Mohamed Ali Radwan

• INTRODUCTION

• STRUCTURE

• CLASSIFICATION

•FUNCTIONS

DISEASES

•CONCLUSION

Research points

INTRODUCTION

Nerve cells—also known as neurons—are the primary building blocks of

the nervous system in humans and animals. On a fundamental level, a

nerve cell functions by transmitting and receiving electrochemical

messages. 

There are approximately 28 billion neurons in the human body penetrating every tissue

in every part. Neurons vary greatly in size and shape, with the longest ones—those that

extend down the leg as part of the sciatic nerve—measuring over one meter. All nerve

cells have a similar structure

STRUCTURE of Nerve cells

DendristsDendrists

Cell BodyCell Body

Myelin sheathMyelin sheath

Synaptic Bulbs

Simple information about the structure

Dendrists: thread-like branches that increase the surface area of the cell making it possible for it to receive many connections with adjoining nerve cells .

Myelin sheath:. Neurons with myelin sheaths are said to be myelinated. They make up myelinated nerves which make up the majority of nerves in the peripheral (nervous system (the nerves outside the brain and spinal cord.

Cell Body: (soma) is the factory of the neuron. It produces all the proteins for the dendrites, axons and synaptic terminals

Types of neurons

Sensory neurons Inter neurons Motor neurons

Neurons exist in a number of different shapes and sizes and can be

classified by their morphology and function.

1 -Structural classification

- Polarity

2-Bipolar 3- Multipolar 1-Unipolar

2 -Functional classification

a- afferentb-efferent c-interneurons

1 -Structural classification

Most neurons can be anatomically characterized as:

Unipolar or pseudounipolar: dendrite and axon

emerging from same process.Bipolar: axon and single dendrite on opposite ends of the soma.

Multipolar: more than two dendrites:Golgi I: neurons with long-projecting axonal processes; examples are pyramidal cells, Purkinje cells, and anterior horn cells.Golgi II: neurons whose axonal process projects locally; the best example is the granule cell.

Afferent neurons convey information from tissues and organs into the central nervous system and are sometimes also called sensory neurons.

Efferent neurons transmit signals from the central nervous system to the effectors cells and are sometimes called motor neurons.

Interneurons connect neurons within specific regions of the central nervous system

Function of nerve cells.

The primary function of the nerve cells of the body is communication. This is accomplished by passing electrical and/or chemical messages from neuron to neuron, or from neuron to other target cells.

The functions of the nerve cells is to carry messages around our body. To adapt to their job, they are very long and are branched at each end

Nerve cells receive, carry, and pass electrical impulses.

Neurons (or nerve cells) are the smallest unit of the nervous system which send signals to the rest of the body to perform what ever function the brain wants it to; such as telling the heart to beat.

Most neurons in the central nervous system cannot

repair or renew themselves, unlike other cells in the

body. So, if some die through illness or damage, the

nervous system can permanently lose some of its

abilities. The symptoms of disorders of the nervous

system depend on which part is attacked–

Alzheimer's disease destroys cells in the memory

area of the brain, for example. There are currently

no cures for these disorders, but promising research

includes new drug treatments, vaccines and nerve

cell transplants.