The sense of balance

Synonym

Vestibular perception

General information

The sense of balance is used for orientation and to determine posture in space. Various sensory organs are necessary for orientation in space. These include the organ of equilibrium (vestibular organ), the eyes and their reflexes, and the interconnection of all stimuli in the cerebellum. Furthermore, the sense of balance contains the sensation for

  • Above and below,
  • Angles and inclinations, and
  • Linear and rotational accelerations of the head.

The vestibular organ

The vestibular organ is composed of The inner ear can be roughly divided into three components:

  • The inner ear with the sense of balance and
  • The cerebellum and its balance functions.
  • The cochlea serves the hearing sensation,
  • Sacculus and Utriculus are used for the perception of linear acceleration and spatial position and
  • Archways (Ductus semicirculares) are used to sense rotational acceleration and rotation.

Sacculus and Utriculus are two interconnected cavities filled with endolymph, each containing a macular organ. The two macular organs of Sacculus and Utriculus are almost perpendicular to each other. The macula utriculi lies horizontally, the macula sacculi vertically.

The macular organs contain supporting and sensory cells which are covered by a gelatinous dome. In this dome there are statoliths consisting of calcium carbonate. Due to the effect of gravity, a shearing force is created during movements between the

  • Statolithic membrane and the
  • Sensory cells.

This triggers stimuli that are transmitted to the brain via the nerve.

Just like sacculus and vestibular perception, the three archways contain sensory and supporting cells. The semicircular arches are circular and are connected to each other as well as to the rest of the inner ear. The three archways are perpendicular to each other and each contain one ampoule.

This ampoule is positioned transversely in the lumen of the arcade and contains the sensory and supporting cells. These are also covered with a gelatinous dome and transmit sensory information through shear forces. Depending on the direction of movement of the individual cells and their speed, the brain can distinguish between the individual movements.

From this vestibular organ from the inner ear the VIII. From this vestibular organ from the inner ear, the cranial nerve, the vestibulocochlear nerve, leads to the corresponding nerve nuclei in the brain stem (vestibular nuclei). Since the information from the inner ear alone is not sufficient to keep the balance, information from the vestibularis nuclei is needed to process this information together.

The vestibularis nuclei are connected to the cerebellum, the spinal cord and the eyes. The connection of the organ of equilibrium with the eye muscle nuclei is called vestibulo-ocular reflex. The cerebellum must be divided into three parts to understand its function: The vestibulocerebellum in particular receives a great deal of information from the inner ear and also sends converted information back to it.

In addition, this part also sends information to the nuclei of the eye muscles and is thus involved in the fine tuning of almost all eye movements. In addition to eye movements, the vestibulocerebellum can also send and receive information to the extrapyramidal pathways of the spinal cord. In this way, the cerebellum has an influence on the supporting motor functions of the trunk.

The spinocerebellum receives a great deal of information from the spinal cord. This enables the cerebellum to send information from the spinal cord to the vestibular organ and the eye muscles and vice versa. This enables constant fine tuning and control between the individual parts of the sense of balance. If one of these important organs fails, dizziness can be triggered, for example.

  • Eye muscles and about the
  • Position of the head in relation to the torso necessary.
  • Vestibulocerebellum,
  • Spinocerebellum and
  • Pontocerebellum.
  • Spinal cord and thus over the
  • Position of the legs and arms, and over the
  • Muscle tone of the trunk.