Question | Answer |
pili (hair) -L- | flexible strands produced by ahir follicles. consist of dead keratinized cells. - functions as protection, sensation and warmth |
shaft | region of hair which projects from skin. determines if hair is curly or straight |
root | region of hair that is embedded in skin |
hair layers | medulla, cortex and cuticle |
medulla | central core of hair, has large cells and air spaces |
cortex (hair) -L- | bulky layer that surrounds medulla,- is pigmented. - has several layers of flattened cells |
cuticle -L- | outermost layer of hair, has a single row of cells that overlap. most heavily keratinized part of the hair which provides strength |
hair pigment | made by melanocytes at the base of hair follicle. different colors come from different portions of melanins |
hair follicle | surrounds the hairs. located in the epidermis down to the dermis - |
hair bulb | deep end of hair follicle with hair follicle receptors wrapped around |
hair follicle receptor | AKA root hair plexus |
hair follicle receptor | wraps around hair bulbs, receptor that is stimulated when the hair is bent |
hair papilla -L- | dermal tissue that protrudes into the hair bulb. has capillaries that supplies nutrients to growing and and signals hair to grow |
wall of hair follicle (laterial to medial) | connective tissue root sheath, glassy membrane, external epithelial root sheath, internale epithelial root sheath |
hair matrix cells -L- | epithelial cells at base of the follicle that divide to produce new hair |
hair bulge | where cells of the hair matrix originate |
arrector pilli -L- | bundle of smooth muscle cells that can pull hair follicle into an upright position and dimple skin surface in response to cold temperatures or fear |
vellus hair | body hair that is fine and pale, found on children and adult women |
terminal hair | coarser, longer hair of the eyebrows and scalp |
hirsutism | excessive hairiness |
alopecia | hair thinning, when hairs are not replaced as fast as they shed |
male pattern baldness | genetically determined, follicle growth cycles become so short that the hairs never emerge from follicles before shedding |
nail -L- | scalelike modification of the epidermis that forms a clear protective covering over finger/toe. contains hard keratin |
regions of nail(distal to proximal) -L- | free edge, body, root |
nail bed -L- | the epidermis below the nail body |
nail matrix -L- | thickest proximal portion of nail bed that is responsible for nail growth |
lunula -L- | region that lies over the nail matrix that appears as a white crescent |
nail folds | skin folds that are overlapping the sides and proximal portion of nail |
cuticle (nail) -L- | proximal nail fold that projects onto the nail body |
hyponychium | region beneath the free edge of nail (where dirt accumulates) |
hair follicle components | external root sheeth (derived from dermis) - glassy (basement) membrane. - internale root sheath, derived from the epidermis |