hair cells


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hair cells

sensory epithelial cells present in the spiral organ, maculae, and cristae of the membranous labyrinth of the ear; they are characterized by having long stereocilia or kinocilia (or both) which, with the light microscope, appear as fine hairs. See: Corti cells.
See also: vestibular hair cells, cochlear hair cells.

Hair cells

Sensory receptors in the inner ear that transform sound vibrations into messages that travel to the brain.
Mentioned in: Cochlear Implants

hair

1. a threadlike keratinized epidermal structure developing from a follicle sunk in the dermis, produced only by mammals and characteristic of that group of animals. Also, the aggregate of such hairs.
2. various other threadlike structures.

auditory h's
hairlike attachments of the epithelial cells of the inner ear.
awn hair
in cats, a short thick, bristly hair underneath the top coat.
hair beds
coat hairs occur in groups of about three primary follicles and a variable number of secondary follicles.
burrowing hair
one that grows horizontally in the skin.
hair cells
sensory neuroepithelial cells which have hair-like processes; found in organ of Corti, ampullary crests and utricle and saccule of the inner ear.
club hair
a hair whose root is surrounded by a bulbous enlargement composed of keratinized cells, preliminary to normal loss of the hair from the follicle.
hair coat
see coat (1).
cover hair
see guard hair (below).
hair follicle
one of the tubular invaginations of the epidermis enclosing the hair roots and from which the hairs grow.
Enlarge picture
Longitudinal section of hair follicle. By permission from Smith BP, Large Animal Internal Medicine, Mosby, 2001
hair follicle unit
hair granuloma
granuloma in the esophageal wall caused by swallowed hairs acting as foreign bodies.
hair growth cycle
a period of growth, called anagen, is followed by a transitional stage, called catagen, and then a period of inactivity in the hair follicle, called telogen, lasting until the cycle starts again. The duration of each stage varies with the species, anatomical location, genetic influence, and a variety of environmental and physiological factors.
guard hair
the coarse, stiff and often longer and more prominent hairs in a haircoat with an undercoat. For example, the darkly colored, outer hairs of a German shepherd dog. Called also primary hair, master hair, cover hair.
ingrown hair
one that has curved and re-entered the skin.
lanugo hair
the fine hair on the body of the fetus.
master hair
see guard hair (above).
primary hair
see guard hair (above).
ringed hair
see thrix annulata.
secondary hair
finer and growing from a more superficial follicle than a guard hair; forms the undercoat.
sensory h's
hairlike projections on the surface of sensory epithelial cells.
sinus hair
the vibrissae or whiskers located on the muzzle and face of many species has an endothelium-lined blood sinus between the inner and outer layers of the dermal portion of the follicle with a rich nerve supply. This structure serves to increase sensory perception.
specialized hair
includes auditory, guard, sensory, tactile, taste, tylotrich hairs (see this list).
hair streams
the hairs in the coat of animals are inclined in one or other direction so that collectively they create streams that meet at vortices or cowlicks.
tactile h's
hairs particularly sensitive to touch.
taste h's
short hairlike processes projecting freely into the lumen of the pit of a taste bud from the peripheral ends of the taste cells.
tipped hair
one with a different, usually darker, color at the tip; seen in Chinchilla cats.
tylotrich hair
special hairs that act as rapid-adapting mechanoreceptors; large, primary follicles with a ring of neurovascular tissue around them. Always associated with a tylotrich pad, a local area of epidermal thickening with a layer of highly vascular and well-innervated connective tissue below.
References in periodicals archive ?
13-19] Impaired functioning of the outer row of hair cells reduces sensitivity to the acoustic stimulus.
Our study results show that EdnrB signalling plays a critical role in growth and regeneration of certain pigmented skin and hair cells and that this pathway is dependent on a functioning Wnt pathway,' said Dr Mayumi Ito, a cell biologist at NYU Langone and senior investigator on the study.
Indirect immunohistochemistry was used to image and allow morphological characterization of the hair cells.
In their latest work, the investigators found that blocking the Notch pathway increases the formation of new hair cells not from remaining hair cells but from certain nearby supporting cells that express a protein called Lgr5.
An OAE test uses a small, very sensitive microphone inserted into the ear canal to monitor the faint sounds produced by the outer hair cells in response to stimulation by a series of clicks.
In October, Roche joined forces with venture capital firm Versant Ventures and biotech Inception Sciences to find molecules targeting ear hair cell protection and regeneration in the cochlea, the spiral-shaped cavity in the inner ear.
This is the first evidence that inner and outer hair cells develop independently of one another," said lead researcher Dr Sung-Ho Huh, from Washington University School of Medicine in St Louis, US.
Humans are born with 30,000 hair cells in each ear.
This leads to permanent damage to the outer hair cells of the cochlea, resulting in permanent hearing loss.
These hair cells are like well-engineered mechanical sensors, similar to those that we use for balance and hearing in the human ear, where the deflection of the jelly-encapsulated hair cell measures important flow information," he said.
A team at the University of Sheffield said they had discovered how to turn stem cells into ones that behave like sensory hair cells or auditory neurons, which could then be surgically inserted into the ear to restore lost hearing.
The work shows that a small number of cells can migrate to the damaged cochlea and repair sensory hair cells and neurons.