What Is the Endolymphatic Sac?

A lymphatic structure found in mammals and humans, mostly oval. Scattered on the path of lymphatic return throughout the body, such as the neck, underarms, groin, iliac crest, elbow, mesentery, and hilum. It communicates with the subdural lymphatic cavity through the thin lymphatic vessels of the endolymphatic sac. It is an important filter for lymphatic reflux and an important place for the body to produce an immune response.

Chinese name: Endolymph
Shape: Oval

Features: Filters lymphatic fluid and participates in immune response
Attributes: Lymphatic structure
Presence: Mammals and humans

Endolymph Endolymph:

The inner ear is filled with lymph fluid, and through the vibration of the lymph fluid, the cochlea can respond to sound stimulation, and the vestibular organs can respond to changes in the spatial position of the body and head. Inner ear lymph fluid is divided into extralymphatic fluid and endolymphatic fluid. The extralymphatic fluid fills the cochlea's drum stage, vestibular step, and vestibular organ membrane labyrinth and bone labyrinth. Endolymph is located in the membranous ducts of the volutes and vestibular organs.

Endolymphatic source:

Because the endolymphatic space is a closed cavity and its composition is similar to the intracellular fluid, the endolymph may be secreted. Various epithelial cells in the endolymphatic space may be involved in the formation of endolymph, such as the cells on the outer surface of the vascular line of the volute, some columnar cells in the epithelium of the ampullate.

Endolymphatic composition:

The electrolyte exists in ionic form when dissolved. The cations in the inner ear lymph fluid are H, Na, K, Ca, Mg, Fe, and Fe, and the anions are Cl, HCO3, HPO4, SO4, I, and organic acids and proteins. Endolymph is characterized by the presence of high concentrations of potassium ions and low concentrations of sodium ions, similar to intracellular fluid. The potassium concentration of endolymph is 30 times higher than that of exolymph, while the sodium ion concentration of exolymph is 10 times higher than that of endolymph. This creates a potential difference between the inside and outside of the resting hair cell membrane.

Endolymphatic clinically relevant diseases-Meniere's disease:

Meniere's Disease (MD) is named after French physician Prosper Meniere. The clinical manifestations of MD are recurrent vertigo, neuromuscular hearing loss, tinnitus and / or ear fullness, and the pathological feature is endolymphatichydrops (ELH).

Endolymph is secreted by vascular striate marginal cells and dark vestibular cells. In addition, various epithelial cells in the endolymph space may participate in its production. Endolymph fluid is located in the membrane spiral canal with both ends blind, and its composition is similar to that of intracellular fluid. It is characterized by the presence of high concentrations of potassium ions and low concentrations of sodium ions. Excessive endolymphatic production and / or reduced absorption can cause ELH, and the resulting functional results depend on when the stagnant water is produced. The mechanical effects of swelling or displacement of the endolymphatic membrane can lead to acute endolymphatic hydrops. Conversely, chronic endolymphatic hydrops can undergo biochemical and morphological changes.

Endolymphatic causes:

Non-progressive hydrops include acute otitis media, chronic otitis media, trauma, external semicircular canal opening, orange bone resection, otosclerosis, Poget's disease, and viral labyrinthitis. Progressive hydrops include Meniere's disease, congenital syphilis, and delayed bone fractures, microscopic bone removal, sudden deafness, mumps, diphtheria, bacterial labyrinthitis, and idiopathic congenital deafness. Sexual water.

Clinical manifestations of endolymph :

The vestibular membrane is shifted to the frontal stage, the balloon is dilated, and its wall is close to the floor of the orange bone. Swelling of the vestibular membrane and moving to the vestibular stage are typical manifestations of ELH. Vestibular membrane rupture may be related to the onset of MD and changes in its function. Changes in vestibular membrane compliance can explain the changes in the degree of stasis in the same patient at different periods.

Clinical diagnosis of endolymph :

It is mainly based on fluctuating deafness, tinnitus, ear fullness, and dizziness. Hearing tests and vestibular examinations may be helpful in diagnosis, but clinically, it is not common for patients to have such symptoms. Researchers believe that the clinical differential diagnosis of progressive and non-progressive hydronephrosis is important because the clinical symptomology depends on the disease that causes the progress of the hydrostasis rather than the hydrostasis itself. There must be a reliable face test that can localize the presence of endolymphatic fluid. The glycerol test is reported to be used for the diagnosis of endolymphatic hydrops, but psychological factors play an important role in this test. Therefore, every patient suspected of endolymphatic hydrops should be examined by neuro-otology to determine Specific causes of water.