The 12 cranial nerves and their functions

The complexity of the nervous system is great. Its multiple connections make this system one of the most important in our body. In this article we will talk about several of its most important pathways: the cranial nerves.

The cranial nerves or nerves arise from the base of the skull and they reach their destination areas through holes distributed throughout it. Thus, they communicate with peripheral areas. Its name is due to the fact that there is a nerve on both sides of the brain. So there are twelve nerves in the right hemisphere and twelve nerves in the left.

Classification of the cranial nerves

The cranial nerves can be classified in different ways:

According to its function.Cranial motor nerves. There are the cranial nerves that are related to eye movements: three, four and five; and the cranial nerves related to movements of the tongue and neck: ten and twelve.sensory cranial nerves: one, two, and eight.Mixed cranial nerves: five, seven, nine and ten.parasympathetic cranial nerves: three, seven.According to your position. Those found above the brain stem (pairs one and two); those found in the upper part of the brain stem (pairs three and four); those close to the bridge (pairs five, six, seven and eight); those found in the lowest part of the medulla oblongata (pairs nine, ten, eleven and twelve).

Now, according to Bear, Connors and Paradiso, authors of the book Neuroscience. brain scan suggest that the first two cranial nerves are part of the central nervous system and the others are like spinal nerves, “in the sense that they contain axons of the peripheral nervous system.” Although, each nerve has fibers that perform various functions.

Cranial nerves and their functions

cranial nerve one

Types of axons: sensory specials.

It is the shortest cranial nerve, since its destination area is close to the area from which it arises in the brain. It is also called the olfactory nerve. Furthermore, as its other name indicates, is responsible for carrying nervous information related to smell.

cranial nerve two

Types of axons: sensory specials.

It originates in the diencephalon. And, like the previous one, it has afferent fibers, that is, they transport nerve impulses from the sensory organs to the central nervous system. Its function is to transmit visual information.

Cranial nerve three

Types of axons: somatic motor and visceral motor.

It is called two other ways: oculomotor nerve or common oculomotor nerve. It is responsible for the movement of the eyes and eyelids. In addition, parasympathetic control of pupil size.

Cranial nerve four

Types of axons: motor somatics.

The fourth pair originates in the midbrain. It is called both the trochlear nerve and the pathetic nerve. It is also responsible for eye movement. Specifically it sends signals to the superior oblique muscle of the eye.

Fifth cranial nerve

Types of axons: sensory somatics and motor somatics.

Known as trigeminal nerve. Account with motor and sensory functions. At a motor level, it sends orders to the muscles responsible for chewing and at a sensory level, it collects tactile, pain, and proprioceptive information from the mouth and face.

sixth cranial nerve

Types of axons: motor somatics.

It is called the Abducens Nerve. It is responsible for the abductor movements of the eye, that is, It is what makes the eye move to the opposite side of the nose. Incredible true?

seventh cranial nerve

Types of axons: sensory somatics, and motor somatics.

Also known as facial pair. It is responsible for the movements of the muscles of facial expression. In addition, the sense of taste in the anterior two thirds of the tongue. Also, it sends orders to the lacrimal and salivary glands.

Eighth cranial nerve

Axon types: sensory specials.

This is the vestibulocochlear nerve. It is responsible for the sense of hearing and balance. Therefore, it receives information about what we hear and the position in which we find ourselves.

Cranial nerve nine

Axon types: somatic motor, visceral motor, special sensory and visceral sensory.

Called glossopharyngeal nerve. It is a mixed nerve, from its name we could deduce some of its functions.

Let’s see what they are:

Movement of the throat muscles. Parasympathetic control of the salivary glands. Detection of blood pressure changes in the aorta. Sense of taste, in the posterior third of the tongue.

Cranial nerve ten

Types of axons: visceral motors.

It is called the vagus nerve. Responsible for parasympathetic control of the heart, lungs, and abdominal organsin addition to the sensation of visceral pain, the movement of the throat muscles and receives gustatory information.

Cranial nerve eleven

Types of axons: motor somatics.

It is called the spinal accessory nerve. It is responsible for the movements of the muscles of the throat and neck.

Twelfth cranial nerve

Types of axons: motor somatics.

Called hypoglossus. Participate in the action of swallowing. Besides, It is responsible for the movement of the tongue, working hand in hand with cranial nerves nine and ten. Thanks to this torque, swallowing is carried out optimally.

Now, any damage to the cranial nerves can mean a problem for our survival or for the functioning of our body. Above all, neurological disorders may be evident. We hope that thanks to this tour we have taken you know this essential part of our body a little better.

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