Cranial nerves final explanation

January 16 / 2018

Stage: c) taking action

Approaches to learning: Transference skills

I found the process of writing this entry quite complex compared to other entries due to the fact that there was a lot of difficult terminology I had to deal with, however, I was able to finally comprehend and write this final explanation.

CRANIAL NERVES:  The cranial nerves are in charge of controlling a big portion of the motor and sensory functions of the head and neck, such as the perception of sight, smell, eye movement and felling in the face. There are 12 cranial nerves located in the human brain, and they all make a part of the peripheral nervous system (PNS). Each cranial nerve is present in each hemisphere of the brain because they all come in pairs. Two cranial nerves originate from the cerebrum, and the other ten come from the brainstem.

The two cranial nerves that come from the cerebrum are the olfatory nerve (I) and the optic nerve (II). The olfactory nerve is in charge of sensing smell, an interesting fact is that it is one of the few nerves that are able to regenerate. And the optic nerve, as suggested by it's name, is in charge of caring visual information (or stimuli) from the retina present in the eye to the brain, meaning it aids in visual functions.

The nerves coming from the brainstem originate from different sections, for example, from the midbrain comes the trochlear nerve (IV), a motor nerve in charge of controlling rotational movement in the eyes.

From the midbrain-pontine junction comes the oculomotor nerve (III), it is in charge of controlling most of the movements the eye performs, the constriction present in the pupil and maintaining an open eyelid. 

From the pons originates the trigeminal nerve (V) it is responsible for the sensation and the motor functions performed by the face and the mouth. 

From the pontine-medulla junction come the abducens nerve (VI) a motor nerve in charge of the lateral movements of the eyes. The facial nerve (VII) controls the muscles involved in facial expressions and taste sensations perceived through the anterior two thirds of the tongue. And the vestibulocochlear nerve (VIII) is responsible for transmitting sound and balancing the information transmitted from the inner ear to the brain. 

Emerging from the pons, the vagus nerve (X) is involved in various tasks such as managing heart rate, gastrointestinal peristalsis, sweating and muscle movements in the mouth. The spinal accessory nerve (XI) is in charge of controlling specific muscles of the neck and the shoulder. The hypoglossal nerve (XII) basically controls tongue movements related to speech, food manipulation and swallowing.  And finally, the glossopharyngeal nerve (IX) receives sensory information from the tongue, the ear, the pharynx and the tonsils.

You may be wondering what the numbers present after the name of each nerve mean, they are all the nerve numbers, and what are they? basically the number of a nerve is the order in which they emerge from the brain, organized from the front of the brain to the back.