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12. Coordination and Control eLearn.Punjab
At the point where a spinal nerve arises from spinal cord, there are two roots of spinal nerve.
Both roots unite and form one mixed spinal nerve (Fig. 12.4).
• The dorsal root contains sensory axons and a ganglion where
cell bodies are located.
• The ventral root contains axons of motor neurons.
Spinal cord is the continuation of medulla oblongata.
Figure 12.4: Spinal Cord and Spinal Nerves
Spinal cord performs two main functions:
1. It serves as a link between body parts and brain. Spinal cord transmits nerve impulses from
body parts to brain and from brain to body parts.
2. Spinal cord also acts as a coordinator, responsible for some simple reflexes.
Peripheral Nervous System
The peripheral nervous system (PNS) is composed of nerves and ganglia. Ganglia are the clusters
of neuron cell bodies outside CNS. Nerves arise or lead to brain and spinal cord. So they are named
as cranial and spinal nerves.
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