Question

The spinal nerves are
A. Only sensory
B. Only motor
C. Some sensory and some motor
D. All mixed nerves

Answer 1

Nervous system is the most complex system present in our body, where it is the one that is needed for the action of the stimuli that takes place and it comprises of two types, that are the central nervous system and the peripheral nervous system. CNS is made up of the brain and spinal cord, whereas the peripheral nervous system is made up of all nerves that connect to the CNS and to all body parts.

Complete answer: Nerves are specialized cells that connect the central nervous system to all the parts of the body. A nerve that carries an outer response or stimuli to the brain are termed as sensory nerves, and the nerve that takes a response from the brain to the target tissue or muscles is called the motor nerve, where some nerves in our body show both sensory and motor actions, and such nerves are usually termed as mixed nerves. Spinal nerves are nerves that arise from the spinal cord to the rest of the body parts and they are a part of the peripheral nervous system. These spinal nerves occur as pairs on either side of the vertebral column, and there are 31 pairs of spinal nerves categorised as cervical, thoracic, lumbar and sacral. All the 31 pairs of spinal nerves are mixed nerves, which shows that they have both sensory and motor action. Each spinal nerve arises from the intervertebral foramen, and they possess two roots; nerve fibres that occur from the dorsal root are afferent sensory nerves, which carries information from the body part or from the external stimulus are efferent motor roots, which take motor information from the brain, therefore, all spinal nerves are mixed nerves.
So, the correct answer is option D.

Note: Spinal nerves are the constituent of the peripheral nervous system and the name has been derived from the spinal cord. In humans, there are 31 pairs: 8 cervical, 12 thoracics, 5 lumbar, 5 sacral and 1 coccygeal. Each pair connects the spinal cord with a specific region of the body.