The vestibular analyzer is a system of nerve structures and mechanoreceptors, which allows a person to perceive and correctly orientate the position of his body in space. Irritants of mechanoreceptors are various kinds of acceleration.
Angular accelerations cause the excitation of ampullar receptors. The straightforward nature of the accelerations contributes to the appearance of pulses in the sensors of the vestibule. The vestibular and ampullar impulses are converted into nerve signals and help the central nervous system maintain orientation in space.
The structure of the vestibular human analyzer
Static reflexes are realized due to the interaction of organs capable of perceiving irritations and transforming them into nerve impulses. Signals go from the vestibular apparatus to the vestibular nerve, through which they enter the areas of the medulla oblongata. On the threshold of the uterus and sac are located. Them
the surface is covered with sensory cells, which are divided into columnar and pear-shaped in shape. Sensitive hairs of these cells are surrounded by an otolith membrane. When the head moves due to gravity, the otoliths are displaced and act on the sensory hairs. The nerve endings that perceive signals from the hairs are connected to the basal part of the sensor cells.
Main functions
A study of the vestibular analyzer revealed five types of reactions that it produces:
- Vestibulosomatic reactions due to vestibulospinal connections. With their help, the vestibular analyzer promotes the redistribution of muscle tone at various accelerations.
- Oculomotor reactions. They are caused by the presence of oculomotor connections and cause involuntary eye movements or nystagmus. This process is biphasic. In the first phase, the ampullar receptor is irritated and the subsequent slow eye movement to the side. In the second phase, as a result of a quick compensating movement, the eyeballs return to their original position. The vestibular analyzer provokes nystagmus for fixing outgoing fragments of the environment during rotational movement. It also helps a person keep track of objects that are moving at high speed.
- Vestibulovegetative functions are adaptivecharacter. When these reactions occur, heart palpitations, increased blood pressure, the appearance of nausea against the background of the action of acceleration are possible.
- Vestibulo-cerebellar reactions occur during active movement. They help to control the position of the body in space when the body is in a dynamic state. This is due to the correct distribution of muscle tone at various accelerations.
- Due to the presence of connections with the cerebral cortex, the vestibular analyzer helps to implement central control and correction of the vestibulosensory reaction.