Question

What are spinal nerves?

Answer 1

Hint: Spinal nerves are the part of the peripheral nervous system which arise from the spinal cord and connect with the rest of the body parts. They are present in pairs and are present on either side of the vertebral column. The spinal nerves are 31 pairs in number.

Complete answer:
The spinal nerves are the important nerves in the peripheral nervous system which connects the spinal cord to the rest of the body. These nerves are mixed nerves which sends motor, sensory and autonomic signals between the central nervous system and the body. The spinal nerves are present on the either side of the vertebral column and are 31 pairs in number. The spinal nerves are categorised as

a) Cervical: These are eight pairs of nerves which arise from the spinal cord through seven cervical vertebrae which are located just below the skull. It provides control and sensation to the different parts of the body depending on the areas of origin. These are numbered from C1-C8 which controls the head, neck and shoulders.
b) Thoracic: These are 12 pairs in number which are present on either side of the spine which controls upper back, chest and abdomen. They mainly control the upper and mid-back.
c) Lumbar: These are five pairs which originate from the either side of the spinal cord below the thoracic spine and above the sacral. They are numbered as L1-L5. They control the sensation in limbs, groin, genital areas etc.
d) Sacral: These nerves arise from the lower part of the spine. They provide sensory information from most of the pelvis and leg. They are 5 pairs and numbered as S1-S5.

Note: The nerves which carry stimuli to the brain is known as sensory nerves. The nerves which carry stimuli from the brain to the target organs is called the motor nerves. The nerves which show both types of response is known as mixed nerves. The nerves of the spinal cord perform all the three roles.