The stria vascularis of the cochlear duct is a capillary loop in the upper portion of the

spiral ligament The spiral ligament is a fibrous cushion located between the stria vascularis and the bony otic capsule. The periosteum, forming the outer wall of the cochlear duct The cochlear duct (bounded by the scala media) is an endolymph filled cavity ...

(the outer wall of the

cochlear duct The cochlear duct (bounded by the scala media) is an endolymph filled cavity inside the cochlea, located between the tympanic duct and the vestibular duct, separated by the basilar membrane and the vestibular membrane (Reissner's membrane) re ...

). It produces endolymph for the scala media in the

cochlea The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory org ...

Structure

The stria vascularis is part of the lateral wall of the cochlear duct. It is a somewhat stratified epithelium containing primarily three cell types: * marginal cells, which are involved in K⁺ transport, and line the endolymphatic space of the scala media. * intermediate cells, which are pigment-containing cells scattered among capillaries. * basal cells, which separate the stria vascularis from the underlying spiral ligament. They are connected to basal cells with

gap junctions Gap junctions are specialized intercellular connections between a multitude of animal cell-types. They directly connect the cytoplasm of two cells, which allows various molecules, ions and electrical impulses to directly pass through a regula ...

. The stria vascularis also contains

pericytes Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body. Pericytes are embedded in the basement membrane of blood c ...

, melanocytes, and

endothelial cell The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vesse ...

s. It also contains intraepithelial capillaries - it is the only epithelial tissue that is not

avascular The blood vessels are the components of the circulatory system that transport blood throughout the human body. These vessels transport blood cells, nutrients, and oxygen to the tissues of the body. They also take waste and carbon dioxide awa ...

(completely lacking blood vessels and

lymphatic vessels The lymphatic vessels (or lymph vessels or lymphatics) are thin-walled vessels (tubes), structured like blood vessels, that carry lymph. As part of the lymphatic system, lymph vessels are complementary to the cardiovascular system. Lymph vess ...

Function

The stria vascularis produces endolymph for the scala media, one of the three fluid-filled compartments of the

. This maintains the ion balance of the endolymph that surround

inner hair cells Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. ...

and

outer hair cells Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. ...

of the

organ of Corti The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. Transd ...

. It secretes lots of K⁺, and may also secrete H⁺.

References

External links

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at

University of New England, Maine The University of New England (UNE) is a private research university in Maine with campuses in Portland and Biddeford, as well as a study abroad campus in Tangier, Morocco. During the 2020 academic year, 7,208 students were enrolled in UNE's cam ...

*
Diagram
at IUPUI Ear {{anatomy-stub