Nervous Tissue

NERVOUS TISSUE

Nervous tissue is responsible for control and communication in the body.

The basic structural and functional unit is the neuron.

A neuron has three main parts:

1. Cell Body (Soma)

• Contains nucleus
• Controls metabolic activities
• Gives rise to axon and dendrites

2. Axon

• Longest part of neuron
• Carries impulses away from the cell body
• May be covered by:
• Myelin sheath (fatty insulation)
• Neurilemma (outer covering)

Breaks in the myelin sheath are called Nodes of Ranvier.

3. Dendrites

• Short, branched projections
• Carry impulses towards the cell body

Synapse

A synapse is the junction between the axon of one neuron and the dendrite of another.

Location

Brain, spinal cord, peripheral nerves

FUNCTIONS OF NERVOUS TISSUE

1. Generates and transmits nerve impulses
2. Responds to internal and external stimuli
3. Communicates information throughout the body
4. Coordinates body activities
5. Produces neurotransmitters
6. Provides insulation and support