The "12 nervous system" refers to the 12 cranial nerves, which are a set of paired nerves that stem from the brain. They play a vital role in various bodily functions, including sensory perception, motor control, and autonomic regulation.
Here's a list of the 12 cranial nerves, their functions, and some basic information about each:
- Olfactory Nerve (I): Responsible for the sense of smell.
- Optic Nerve (II): Transmits visual information from the eyes to the brain.
- Oculomotor Nerve (III): Controls eye movements, pupil constriction, and eyelid opening.
- Trochlear Nerve (IV): Controls the superior oblique muscle of the eye, responsible for downward and outward eye movement.
- Trigeminal Nerve (V): Has both sensory and motor functions. It controls facial sensation, chewing, and the sensation of the cornea.
- Abducens Nerve (VI): Controls the lateral rectus muscle of the eye, responsible for outward eye movement.
- Facial Nerve (VII): Controls facial expressions, taste sensation on the anterior two-thirds of the tongue, and tear and salivary gland secretion.
- Vestibulocochlear Nerve (VIII): Responsible for hearing and balance.
- Glossopharyngeal Nerve (IX): Controls taste sensation on the posterior one-third of the tongue, swallowing, and the secretion of saliva.
- Vagus Nerve (X): The longest cranial nerve, it controls heart rate, breathing, digestion, and speech.
- Spinal Accessory Nerve (XI): Controls the sternocleidomastoid and trapezius muscles, which are involved in head movement and shoulder elevation.
- Hypoglossal Nerve (XII): Controls the tongue muscles, responsible for speech and swallowing.
