There are 12 pairs of cranial nerves. They start from the bottom of the brain. They travel through the holes in the skull to the their target.
III. Oculomotor-eye movement
IV.Trochlear- eye movement
IV. Trigeminal -face sensation and chewing
VI. Abducens – eye movement
VII. Facial nerve- taste facial expressions , ear sensations
VIII. Vestibulocochlear Nerve -hearing balance
IX. Glossopharyngeal nerve - taste and swallowing
X. Vagus -glands digestion and heart
XI. Spinal accessory nerve - controls muscles in head movement.
XII. Hypoglossal Nerve- controls tongue.
Spinal nerves arise from the spinal cord through open areas in the spinal column. Each nerve has two short arms (called spinal nerve roots). One arm goes to front of the spinal cord and the other goes to the back. The motor nerves are at the front and carry commands from the brain and spinal cord to other parts of the body, especially to the skeletal muscles. The back branches , are sensory nerves, and carry information about the body’s position, light, touch, temperature, and pain to the brain from other parts of the body.
The spinal cord’s main use is to transport information from the brain to the peripheral nervous system or vice versa. But we can’t give all the credit to the spinal cord because without a bony spinal column made up of bones called vertebrae to protect it the spinal cord would be nothing. On average men have 45 cm spinal cords while women have a 43 cm long spinal cord. But the funny thing is that the actual spinal cord ends before the bony spinal column ends. So that means that nerves that branch from the spinal cord (from the lumbar and sacral levels) must run in the vertebral canal for a distance before they exit the vertebral column. The nerves in the vertebral canal are called the cauda equine. The grey matter in the spinal cord is called “grey matter” and contains the cell bodies. The white matter is cell tracks. The cord is covered by the meninges and three layers called the pia, subarachnoid and dura matter.
A nerve cell is called a neuron and is made up of the cell body and nerve fibers. The fibers are usually either the axon for sending information or the dendrite for receiving information.
The axons are covered by myelin an insulator. It makes sure the electrical signals do not get lost and travel at fast spe