hair (hār) pilus; a threadlike structure, especially the specialized epidermal structure composed of keratin and developing from a papilla sunk in the dermis, produced only by mammals and characteristic of that group of animals. Also, the aggregate of such hairs.hair´y 
hair [hār]
)
Hair in longitudinal section (A), and in cross section (B), showing the surrounding root and dermal sheaths.
bamboo hair trichorrhexis nodosa.
beaded hair hair marked with alternate swellings and constrictions, as in monilethrix.
burrowing hair one that grows horizontally beneath the surface of the skin.
club hair one whose root is surrounded by a bulbous enlargement composed of keratinized cells, preliminary to normal loss of the hair from the follicle.
ingrown hair one that emerges from the skin but curves and reenters it.
lanugo hair lanugo.
resting hair see telogen.
sensory hairs hairlike projections on the cells of sensory epithelium.
taste hairs clumps of microvilli that form short hairlike processes projecting into the lumen of a taste pore from the peripheral ends of the taste cells. 
)
Taste hairs protruding from the pore of a taste bud.
terminal hair the coarse hair on various areas of the body during adult years.
twisted hair one which at spaced intervals is twisted through an axis of 180 degrees, being abnormally flattened at the site of twisting.
vellus hair vellus (1).
| beaded hair n. See monilethrix. |
hair [hār]
1. any thin, threadlike structure.
2. especially, the specialized epidermal structure produced only by mammals, developing from a papilla sunk in the corium. The life cycle of a hair (hair cycle) consists of three phases, called anagen, catagen, and telogen. Called also pilus.
Structure of hair and hair follicles. From Applegate, 2000.
3. the aggregate of such structures.
bamboo hair trichorrhexis nodosa.
beaded hair hair marked with alternate swellings and constrictions; seen in monilethrix.
burrowing hair one that grows horizontally in the skin, causing a papule that may become infected; see also pili cuniculati, under pilus.
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.
Frey's h's stiff hairs mounted in a handle; used for testing the sensitiveness of pressure points of the skin.
ingrown hair one that has curved and reentered the skin, causing a papule that may become infected. See also pili incarnati, under pilus.
lanugo hair the fine hair on the body of the fetus.
moniliform hair beaded hair.
pubic hair the hair on the external genitalia; called also pubes.
sensory h's hairlike projections on the surface of sensory epithelial cells.
tactile h's hairs 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.
terminal hair the coarse hair on various areas of the body during adult years.
twisted hair a hair that is twisted through an axis of 180 degrees at spaced intervals, being abnormally flattened at the site of twisting. See also pili torti, under pilus.
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