nervous system includes the brain and spinal cord extending from their nerves and their ramifications.All nerve branch connected to the peripheral nervous system.There are 12 pairs of cranial nerves and 31 pairs of spinal.Each pair has its own name and number, which is indicated by a Roman numeral.Cranial nerves are located in the base of the brain.On the composition of the nerve fibers, released their three functions: motor, sensory and mixed.
sensitive cranial nerves are formed from fibers of neurons that lie outside the brain.These include olfactory, visual and auditory nerves.They provide vestibular function, hearing, sight and smell.The first pair begins from nerve cells located in the nasal mucosa.With the defeat of the nerve, there is complete loss of the ability to smell.The second pair - is the optic nerve, which originates in the cells of the retina.His atrophy leads to a sharp decrease in visual acuity, and sometimes blindness.The eighth pair of auditory nerves responsible for hearing and vestibular activity.In violation of his work there is dizziness, hearing loss, ataxia, vestibular dysfunction.
Motor function comprises five pairs of nerves.They originate in the motor nuclei of the trunk.The third, fourth and sixth pair of nerves associated with the device and eye movements.Oculomotor nerve - this is the third pair.It is formed by the fibers, starting from the nuclei of the same name.The parasympathetic fibers contained in this nerve, innervate the muscles of the eye.The affected cranial nerves III are characterized by a pair of upper eyelid ptosis, exotropia, and pupil dilation.With the defeat of IV nerve block in vision observed doubling of subjects.When the eyes lowered down, appears slight squint.If disrupted the activities VI abducens, changes the movement of the eyeball out, this leads to a convergent squint and double vision.
facial nerve (VII) controls the facial muscles.Additionally, it contains fibers and has a taste sensitivity autonomic fibers that regulate the function of the salivary and lacrimal glands.Additional XI nerve regulates certain types of muscle function.With his defeat appears paresis or paralysis of the muscles.Last, the hypoglossal nerve XII, is connected with the tongue muscles.In case of violation of this nerve activity observed restriction of mobility and deviation of the tongue forward it to the affected side.Manifested muscle atrophy, pain of the tongue, fibrillar twitching.
Mixed function of cranial nerves carry V, IX, and X are couples.Fifth, the trigeminal nerve controls the chewing muscles and provides the sensitivity of the person.Glossopharyngeal (IX) nerve is responsible for salivation, taste and for the state of the throat and tongue.Vagus (X) nerve provides sensitivity rear portions of the oral cavity, larynx and pharynx.He is responsible for the functioning of muscles.Cranial nerve X pairs provide parasympathetic relationship of internal organs.
If it affects the trigeminal nerve, there are attacks of sharp pain neuralgic character in the relevant areas of the face.They are accompanied by reddening and lacrimation.When pathology IX couples feel pain in the throat, there is difficulty in swallowing, taste disorder seen, broken salivation.With the defeat of the vagus nerve abnormalities arise in the activities of internal organs.With bilateral lesions observed swallowing disorder, nasal tone of speech, pain in the ear.Such violations are always accompanied by severe prognosis.
