Question

Cranial nerves arise from the brain and they are twelve in number
A. True
B. False

Answer 1

Hint: Cranial nerves are nerves of the brain. The brain is a part of the Central Nervous System, so cranial nerves play an important role in all the functions of the body such as eyeball movement, smelling, sight, speech, etc.

Complete step by step answer: Twelve pair of nerves that emerge from the brain are called cranial nerves. They are present on both sides of the brain.
The function of Cranial nerves are as follows:
i. They help to receive sensory signal and give a motor signal from the brain to the head, neck and to the sense organs.
ii. The twelve pair of cranial nerves name according to their structure performed and function.
Origin and functions of the twelve cranial nerves:

S.No.	Name	Origin	Nature	Functions
1.	Olfactory	Olfactory lobe	Sensory neuron	Smelling
2.	Optic	Optic lobe	Sensory neuron	Sight
3.	Oculomotor	Midbrain	Motor neuron	Eyeball movement
4.	Trochlear	Midbrain	Motor neuron	Rotation of eyeball
5.	Trigeminal	Pons	Sensory neuron	Provide sensation of the skin and control chewing muscle
6.	Abducens	Pons	Motor neuron	Rotation of eyeball
7.	Facial	Pons	Sensory neuron	Movement of the neck, chewing and facial expression
8.	Auditory	Medulla	Sensory neuron	Hearing
9.	Glossopharyngeal	Medulla	Sensory, Motor	Movement of pharynx
10.	Vagus	Medulla	Sensory, Motor	Slow down heartbeat rate, peristaltic movement, speech
11.	Spinal accessory	Medulla	Motor	Muscles of pharynx, neck, larynx, shoulder movement
12.	Hypoglossal	Medulla	Motor	Movements of tongue

Note: Peripheral Nervous System consists of cranial nerves and spinal nerves. Spinal nerves are 31 pairs in human. Hypoglossal is a cranial nerve which is not present in cyclostomes, fishes and amphibians.