Cranial nerves comprise twelve pairs of nerves,beginning in the brain and serving a variety of muscles, glands, internal organs, as well as a sensory apparatus of the neck and head. These pairs are directly related to the activities of such functions as motor, sensory, secretory and reflex. Cranial nerves are located in different parts of the brain. Thanks to these nerves, there are many processes associated with the work of all organs of the human body. They in a certain sequence move away from the brain. Traditionally, the anatomy of the cranial nerves is indicated by Roman numerals.
The first is the olfactory nerve.Its receptors are located in the upper region of the nasal cavity, in the mucous membrane. The nerve consists of about twenty thin in structure threads. These strands do not have a common trunk, and the skull region penetrates through the trellis plate of bone, attaching to the cells of the olfactory bulb, which is represented by a set of mitral cells. The impulse passes to them to the primary centers of smell, and thence to the cortex of the brain.
The second pair forms the optic nerve. Its function is to deliver information from the retina, which is a light-absorbing shell of the eye.
The fibers of this nerve originate from the ganglionic cells that make up the retina of the eye. The nerve, formed by these fibers, passes through the orbits, and from there - into the cranial cavity.
The third pair is the oculomotor nerve.Its nucleus is located on the same line with the upper bulges of the midbrain. It is divided into the lower and upper branches, which are connected to the muscle lifting the upper eyelid, and to the lower oblique muscle of the eyeball.
IV pair is called the nerve block.It refers to the motor nerves. Its core is located in the middle brain. Bypassing the foot of this brain from the lateral side, the nerve block exits to its base, located between the temporal lobe and the pedicle. Further, this nerve, together with the oculomotor nerve, passes from the cranial region directly to the orbit.
V pair forms a trigeminal nerve, which alsoenters the cranial nerves. Even in the cranial region, it is divided into three large branches. This nerve makes the eyes and the forehead sensitive. The skin of the face between the mouth and the eye, and also the mucous nasal and upper parts of the oral cavity innervates the maxillary nerve. The facial skin located below the mouth, the oral mucosa, the lower teeth, the tongue innervates the mandibular nerve. Also under his control are chewing muscles.
The sixth pair represents the abducent nerve.Its core is located in the area of the bridge. The nerve controls the eye muscles, which are responsible for the position of the eyeball and its movement. If it is damaged, strabismus may occur.
The facial nerve that forms the VII pair is also included in thecranial nerves. Its branches are divided into temporal, buccal and zygomatic. The nerve innervates the facial muscles, and its intermediate part, called autonomic, controls the salivary glands and the taste sensitivity of the tongue.
VIII pair is represented by pre-cochlearnerve. This is the nerve of the auditory organ. It consists of the vestibule root and cochlear. The roots begin inside the pyramid in the thickness of the temporal bone in the inner ear.
IX pair is called the glossopharyngeal nerve. It is the nerve of the taste sensitivity of the posterior region of the tongue, which also participates in the parotid salivary gland and the swallowing process.
X pair represents a vagus nerve.It is directly related to speech and swallowing. Innervates muscles of pharynx, palate, larynx. The nerve is divided into many branches directed to the organs of the head and neck, as well as of the abdominal and thoracic cavities.
XI pair is called an additional nerve. He takes his origin from the medulla oblongata and controls the trapezius muscle, as well as the sternocleidomastoid-mastoid.
XII pair forms a sublingual nerve. He innervates all the muscles of the tongue without exception.
Human nerves are responsible for the operation of all systems andbodies. They are susceptible to various changes in the environment, causing unpleasant pain, and can lead to malfunctioning of whole body systems.
