Endolymphatic sac

Endolymphatic sac is a part of the inner ear that plays a crucial role in maintaining the volume and ionic composition of the endolymph. It is involved in the pathophysiology of Meniere's disease, a disorder of the inner ear that can lead to dizzy spells (vertigo) and hearing loss.

Anatomy

The endolymphatic sac is located in the posterior cranial fossa, near the sigmoid sinus. It is connected to the saccule and utricle of the inner ear through the endolymphatic duct. The sac is divided into two parts: the proximal (utricle) end, which is lined by a single layer of flat cells, and the distal (saccule) end, which is lined by multi-layered cuboidal cells.

Function

The endolymphatic sac is responsible for maintaining the volume and ionic composition of the endolymph. It does this by absorbing endolymph and secreting potassium ions. The sac also plays a role in the immune response of the inner ear, as it contains cells that can produce antibodies and other immune molecules.

Clinical significance

The endolymphatic sac is involved in the pathophysiology of Meniere's disease. In this condition, the sac is unable to properly regulate the volume and ionic composition of the endolymph, leading to an excess of endolymph (endolymphatic hydrops) in the inner ear. This can cause symptoms such as vertigo, hearing loss, and tinnitus.

See also

• Inner ear
• Meniere's disease
• Endolymphatic hydrops

References

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