The olfactory tract and bulb, the corpora quadrigemina, corpora genicolate, optic thalamus, corpora striata, are all more or less mixed. They possess gray matter.
The nerves immediately connected with the brain are of several kinds. And there are twelve pairs of them. They are called cerebral nerves.
The nerves of special sense may with great propriety be termed the nerves of observation, perception--the gateways of intelligence and education.
1. The olfactory supplies the nose, special sense of smell.
2. The optic supplies the eye, special sense of sight.
3. The auditory supplies the ear, special sense of hearing.
4. Part of the glosso-pharyngeal supplies the tongue and pharynx.
5. The gustatory, lingual branch of the fifth, supplies the tongue, sense of taste.
2. The superior maxillary supplies the upper jaw and teeth.
3. The inferior maxillary supplies the lower jaw and teeth.
1. The third nerve, motor acuti. } } 2. The fourth nerve, trochlear or } Supply the muscles pathetic. } of the eye. } 3. The fifth, branch of fifth. } } 4. The sixth, abducers. }
5. The facial nerve supplies the muscles of the face.
6. The hyperglossal supplies the muscles of the tongue.
1. The pneumogastric supplies lungs, heart, stomach, larynx, etc.
2. The spinal accessory supplies some muscles of the back.
The average weight of the brain in the adult male is about 49 1/2 ounces, a little more than three pounds avoirdupois; in the female 44 ounces; the average difference between the two being from 5 to 6 ounces.
The spinal cord has a length of about 16 to 17 inches, and weighs about 1 1/2 ounces.
The spinal cord is a continuation of the medulla oblongata, is lodged in the spinal canal, and gives off 31 pairs of nerves, that supply all the muscles of the body with sensitive and motor nerves.
The medulla oblongata is pyramidal in form, having its broad extremity upwards. It is expanded laterally at its upper part. Its length from the pons varolii to the lower extremity of the pyramid is about an inch and a quarter; its greatest breadth is nearly an inch; and its thickness from before backwards is about three-quarters of an inch.
The medulla is the link between the brain and the spinal cord. The majority of centers for various organic functions are situated in it; as follows: