Neurons are the basic building blocks and information processors of the nervous system. They have a cell body containing the nucleus, and long projections called axons and dendrites. Axons carry electrical signals away from the cell body to transmit information to other neurons or target cells. Dendrites receive electrical signals from other neurons and carry them towards the cell body. The neuron is insulated by myelin sheaths along the axon which allows rapid signal transmission. Gaps in the myelin called nodes of Ranvier allow signals to hop between nodes. Neurons communicate with each other at junctions called synapses.

1. STRUCTURE
OF NEURON
Presented by
ARATHY CHANDRAN

2. NEURON
 Defined as nerve cell
 Building block of nervous system
 Miniature self – contained information processor
 Receives input – processes information – generates
output
 Communicate with other neurons through chemical
signals

3. STRUCTURE

4. CELL BODY
 Part of neuron containing nucleus but not
incorporating axon and dendrites

5. AXONS
 aka Nerve fibre
 Long, slender projection of a nerve cell
 Conducts electrical impulses away from neuron’s
cell body
 Function : Transmit information to different neurons,
muscles and glands

6. DENDRITES
 Branched projections of a neuron
 Conduct the electro chemical stimulation received
from other neural cell to the cell body of the neuron
from which the dendrites project.

7. NEURILEMMA
 Outermost nucleated cytoplasmic layer
 Surrounds axon of the neuron
 Forms the outermost layer of the nerve fibre in the
Peripheral Nervous System

8. MYELIN SHEATH
 Fatty material made by glial cells
 Insulates the axon
 Allows rapid movement of electrical impulses along
axon

9. NODES OF RANVIER
 Gaps in myelin sheath where action potential are
terminated
 Multiple sclerosis is a breakdown of nodes of
ranvier

10. SYNAPSE
 Junction where the axon or some other portion of
one cell terminates on the dendrites, soma or axon
of another neuron

11. TYPES OF NEURON
 Sensory (afferent) neurons
 receptors detect changes in body and external
environment
 this information is transmitted into brain or spinal
cord
 Inter neurons (association neurons)
 lie between sensory & motor pathways in CNS
 90% of our neurons are inter neurons
 process, store & retrieve information
 Motor (efferent) neuron
 send signals out to muscles & gland cells
 organs that carry out responses called effectors

12. PART FUNCTION
AXON Carry nerve impulses away from cell
DENDRITES Carry nerve impulses towards nerve
cell
SCHWANN’S CELL Protective myelin sheath around the
axon of medullated nerve fibres
NUCLEUS Control the activity of the cell
MYELIN SHEATH Protection of the nerve fibre, Insulation
of the nerve fibre, Increases the rate of
transmission of nerve impulses

13. PART FUNCTION
NODES OF RANVIER Allowing nutrients and waste
products to enter and leave the
neuron
Allowing nerve impulses to move
along the neuron through a
process of polarisation and re –
polarisation of the nerve
membrane
SYNAPSE Reaching a synapse, an impulse
causes the release of a
neurotransmitter, which diffuses
across the gap and triggers an
electrical impulse in the next
neurone