The vagus nerve

The vagus nerve (nervus vagus) - X pair of cranial nerves; contains sensory, motor and autonomic fiber. Sensory fibers of the vagus nerve begin from two sites outside of the skull,upper (ganglion superius) and lower (ganglion inferius). The top contains false unipolar cells at the bottom along with them meet and multipolar.
Central extensions of these cells formations in structure of the spine of the vagus nerve included in the medulla through the rear lateral sulcus (sulcus lateralis post.), heading back, are part of solitary beam (tractus solitarius) and are divided into short ascending and long descending branch. Rising fibres end in the nucleus alae cinereae (BNA), and a large part of the descending fibres - nucleus tractus solitarii where gelatinous substance solitary beam. Solitary beam gradually becomes thinner at the level of the decussation of the pyramids in the cervical Department of a spinal cord disappears. From these sensitive nuclei located in the medulla (Fig. 1)derives Central sensitive neuron of the vagus nerve. The inner part trigonum n. vagi busy vegetative (moralnym kernel, B. N. (nucleus dorsalis p. vagi).
To the motor nuclei of the vagus nerve belongs located in the reticular formation on clinico oblong brain nucleus ambiguus, common for X and IX pairs of cranial nerves. Cells of motor kernels of large dimensions; their axons are sent back, connecting with sensitive fibers, turn outwards and forward and out of the medulla oblongata at the level of the rear side grooves, forming together with sensitive fibres one massive trunk vagus nerve, which leaves a cavity of a skull through the jugular hole. When exiting it gets ramus internus from incremental nerve (nervus accessorius, XI pair), lies between the internal carotid artery and the internal jugular vein, and then between Vienna and common carotid artery descends into the chest cavity, where innervates the esophagus, forming plexus his sides (plexus oesophageus).
The vagus nerve has a vast area of innervation (Fig. 2). Together with esophageal it penetrates into the abdominal cavity, forms plexus on the walls of the stomach and gives branches other digestive organs, respiratory organs and heart. Sensitive fibers vagus nerve innervated by the occipital departments of Dura mater, the ear canal, the rear surface of the auricle, the soft palate, throat, larynx. In addition sensitive and secretory fibers, part of the vagus nerve includes motor fibers of the muscles of the larynx, pharynx, esophagus, stomach and intestines and vasomotor fiber for vessels and the heart. Heart vasomotor fiber receive from B. N. fiber, check the heartbeat.
The composition of heart branches Century ad is nervus depressor (animals representing independent branch), which is sensitive nerve for the heart and the initial part of the aorta is a regulator of blood pressure. The vagus nerve is involved in many reflex acts (swallowing, cough, vomiting, filling and emptying of the stomach), is also involved in regulation of heart rate, breathing. With the duplex vagus nerve transection come disorders that involve death.
With the defeat of motor nuclei B. N. experiencing problems with swallowing, phonation, articulation, breathing, which are called bulbar symptoms. They occur when the tabloid paralysis, amyotrophic lateral sclerosis, ascending paralysis Landry, polyencephalic, diseases of the peripheral nerve involvement in the process B. N. and his roots and other diseases; the appearance of these symptoms makes the prediction of these diseases heavy. During operations in the chest and abdomen may come irreversible cardiac arrest in the reflex stimulation of the vagus nerve, which can be prevented its blockade.

Fig. 1. The vagus nerve and its core in the medulla: 1 - nucleus dorsalis n. vagi; 2 - nucleus n. hypoglossi; 3 - ventriculus IV; 4 - tractus solitarius et nucleus tractus solitarii; b-n. hypoglossus; 6 - ganglion superius n. vagi; 7 - ganglion inferius n. vagi; 8 - tractus corticospinalis (pyramis); 9 - lemniscus medialis; 10 - oliva; 11 - substantia reticularis; 12 - nucleus ambiguus.

Fig. 2. The topography of the vagus nerve: 1 - n. vagus; 2 - n. laryngeus sup.; 3 - r. cardiacus sup.; 4 - n. laryngeus recurrens; 5 - year cardiacus inf.; in - rr. bronchiales; 7 - truncus vagalis ant.; 8 - rr. gastrici ant.