Biology, asked by Nidhichaudhary4503, 1 year ago

Name the 12 pairs of cranial nerves and their functions

Answers

Answered by Quadbros
5
I- Olfactory Nerve

It’s the first of the 12 pairs of cranial nerves. It’s a sensory nerve, in charge of transmitting olfactory stimuli from the nose to the brain. Its actual origin is given by the cells of the olfactory bulb. It is the shortest cranial pair of all. 

II- Optic Nerve

This cranial pair is the second of the 12 pairs of cranial nerves and it is responsible for conducting visual stimuli from the eye to the brain. It is made of axons from the ganglion cells of the retina, that take the information of the photoreceptors to the brain, where later it will be integrated and interpreted. It emerges in the diencephalon.

III- Oculomotor

This cranial nerve is also known as the common ocular motor nerve. It is the third of the 12 pairs of cranial nerves. It controls eye movement and is also responsible for pupil size. It originates in the midbrain.

IV- Trochlear

This nerve has a motor and somatic functions that are connected to the superior oblique muscle of the eye, being able to make the eyeballs move and rotate. Its nucleus also originates in the mesencephalon as well as the oculomotor nerve. It is the fourth of the 12 pairs of cranial nerves.

V- Trigeminal

It is a mixed cranial nerve (sensitive, sensory and motor), being the largest of all cranial nerves, it is the fifth of the 12 pairs of cranial nerves. Its function is to carry sensitive information to the face, to convey information for the chewing process. The sensory fibers convey sensations of touch, pain, and temperature from the front of the head including the mouth and also from the meninges.

VI- Abducent

It is also known as the external ocular motor cranial nerve and it is the sixth of the 12 pairs of cranial nerves. It is a cranial motor pair, responsible for transmitting the motor stimuli to the external rectus muscle of the eye and therefore allowing the eye to move to the opposite side from where we have the nose.

VII- Facial or Intermediate

This is another mixed cranial pair since it consists of several nerve fibers that perform different functions, like ordering the muscles of the face to create facial expressions and also send signals to the salivary and lacrimal glands. On the other hand, it collects taste information through the tongue. It is the seventh of the 12 pairs of cranial nerves.

VIII- Vestibulo-Cochlear

It is a sensory cranial nerve. It is also known as the auditory and vestibular nerve, thus forming vestibulocochlear. He is responsible for balance and orientation in space and auditory function. It is the eighth of the 12 pairs of cranial nerves.

IX-Glossopharyngeal 

It is a nerve whose influence lies in the tongue and pharynx. It collects information from the taste buds (tongue) and sensory information from the pharynx. It leads orders to the salivary gland and various neck muscles that help with swallowing. It also monitors blood pressure. It is the ninth of the 12 pairs of cranial nerves.

X-Vagus 

This nerve is also known as pneumogastric. It emerges from the medulla oblongata and supplies nerves to the pharynx, esophagus, larynx, trachea, bronchi, heart, stomach and liver. Like the previous nerve, it influences the action of swallowing but also in sending and transmitting signals to our autonomous system, to help the regulate activation and control stress levels or send signals directly to our sympathetic system. It is the tenth of the 12 pairs of cranial nerves.

XI-Accessory 

This cranial pair is named the spinal nerve. It is a motor nerve and could be understood as one of the most “pure”. It governs movements of the head and shoulders by supplying the sternocleidomastoid and trapezius muscles in the (anterior and posterior) regions of the neck.  The spinal nerve also allows us to throw our heads back. Thus, we would say that it intervenes in the movements of the head and the shoulders. It is the eleventh of the 12 pairs of cranial nerves.

XII-Hypoglossal 

It is a motor nerve which, like the vagus and glossopharyngeal, is involved in tongue muscles, swallowing and speech. It is the twelveth of the 12 pairs of cranial nerves.

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