Cranial nerves is a type of nerve which comes out from the brain directly. This is totally different from the spinal nerves which come out from spinal cord segments. Generally a normal human being consists of twelve pairs of these types of nerves. The first and second pair comes out from the part of the brain known as cerebrum. The other ten pairs come out from the brainstem.
These nerves are being named by the help of roman numerical according to an order by which they appear from different key parts of the body. A human cranial nerves is similar to those nerves that are found in animals. The nervous system comprises of these types of nerves. Trigeminal is the largest cranial nerves present in the body. Vagus nerve is the longest. It starts from medulla oblongata and ends at urinary organs.
Types of cranial nerves
- The Olfactory nerve- These are purely sensory. The sense of smell is transmitted by this nerve. It is found in olfactory foramina.
- Optic nerve- These are purely sensory. It is found in the optic canal. It provides the brain with visual effects.
- Oculomotor nerve- It is mainly motor. It helps to supply a part with nerves. Eye functions are performed by these nerves.
- Trigeminal nerve- It is both motor and sensory. These nerves receive pulses from the face and help to provide the muscles of mastication to a part. These are also found in the superior orbital fissure.
- Trochlear nerve- It is mainly motor. It helps to supply a part with the superior oblique muscle. This is also found in the superior orbital fissure.
- Abducens nerve- These are mainly motor. Lateral rectus is provided by these nerves which disturbs the eye movement. These are found in the superior orbital fissure.
- Facial nerve- It is both sensory and motor. It receives taste sensations. It is found in the internal acoustic canal.
- Vestibulocochlear nerve- It is mainly sensory. This is a type of cranial nerves that helps a person to balance and move. It is found in the internal acoustic canal.
- Vagus nerve- It is both sensory and motor. Parasympathetic fibers are provided by these nerves. It fixes voice muscles. It is found in jugular foramen.
- Accessory nerve- It is mainly motor. It controls the strength of a body. It is found in jugular foramen.
- Glossopharyngeal nerve- It is both sensory and motor. Provides parotid gland, secretes fluid in the tongue and operates on other taste sensations. It is found in jugular foramen.
- Hypoglossal nerve- It is mainly motor. It helps in suave articulation and helps to control speech problems and swallowing. It is found in the hypoglossal canal.
Mnemonic devices- A small introduction
It is very important to remember the list of this nerve. Cranial nerves is an important aspect of a human body. While examining the nervous system it is obligatory to think about these devices called mnemonic devices. These devices help to remember the type of these nerves in a certain order. These devices are plenty in number.