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1.1 Nervous System

Look at the picture and discuss.
a. What do you see in the picture? What does
it do?
b. Which organ system controls the functions
of sensory organs such as smell, taste, heat,
cold, etc.?

c. By which organ system are other functions
such as respiration, circulation, urination,
feeding behaviour, etc. controlled and commanded?
The nervous system is Dendrlte
Node cl RSIWier
n1ade up of neurons. Schwann Cell
The basic unit of the
nervous system is a
nerve cell or neuron.
The neuron contains
an axon, dendrites and
nucleus. The special
extensions are axons
and dendrites. The
axons are tail-like structures and the dendrites are fibrous roots. The
axons are longer than the dendrites. There is a nucleus in the middle
of the nerve cell which is enclosed by protoplasm.
The nervous system controls and coordinates the internal and external
activities of the human body. It also gives the necessary command to
other organ systems. Therefore, it is also known as 'Master Syste1n or
Coilllnand Centre'. It has three main parts: Central Nervous System,
Peripheral Nervous System and Automatic Nervous System.
A. Central Nervous Systen1

The central nervous system (CNS) consists of the brain and spinal
cord. The brain controls how we think, learn, move, and feel, whereas
the spinal cord carries messages back and forth between the brain
and the nerves that run throughout the body.It is known as the centre
because it combines information from the entire body and coordinates
the activities across the whole organis1n.
2 Health, Physical ai1d Creillive arts, grade 8