Integumentary System - Hair Flashcards
Hair consists of _______________________ .
Dead keratinized cells
Hair is not located on . . .
Palms, soles, lips, nipples and portions of external genitalia
Hair functions:
- warn of insects on skin
- hair on head guards against physical trauma
- protect from heat loss
- shield skin from sunlight
Hairs also called _________, consists of . . .
Pili
Flexible strands of dead keratinized cells
Hairs are produced by . . .
Hair follicles
Hairs contain . . .
Hard keratin
Regions of hairs:
Shaft
Root
Shaft is . . .
Area that extends above scalp, where keratinization is complete
Roots:
Area within scalp, where keratinization is still going on
Three parts of hair shaft:
Medulla
Cortex
Cuticle
Medulla:
Central core of large cells and air spaces
Cortex:
Several layers of flattened cells surrounding medulla
Cuticle:
Outer layer consisting of overlapping layers of single cells
Hair pigments are made by _____________ in hair follicles
Melanocytes
Combinations of different _____ create all the hair colors
Melanin
Red hair has additional ________ pigment
Pheomelanin
Gray/white hair results when . . .
Melanin production decreases and air bubbles replace melanin in shaft
Hair follicle extends from ______________ to ________
Epidermal surface to dermis
Hair bulb:
Expanded area at deep end of follicle
Hair follicle receptor
Sensory nerve endings that wrap around bulb
Hair is considered a ______________ receptor
Sensory touch
Wall of follicle composed of:
- peripheral connective tissue sheath
- glassy membrane
- epithelial root sheath
Peripheral connective tissue sheath is derived from . . . And is also called . . .
Dermis
Fibrous sheath
Glassy membrane is . . .
Thickened basal lamina
Epithelial root sheath is derived from . . .
Epidermis
Hair matrix:
Actively dividing area of bulb that produces hair cells
As matrix makes new cells it . . .
Pushes older ones upward
Arrector pili:
Small band of smooth muscle attached to follicle
Arrector pili are responsible for . . .
Goose bumps
Hair papilla
Dermal tissue containing a knot of capillaries that supplies nutrients to growing hair
Vellus hair
Pale, fine body hair of children and adult females
Terminal hair
Coarse, long hair
Terminal hair is found on . . .
Scalp and eyebrows
At puberty terminal hair appears in . . .
Axillary and pubic regions
Face and neck of males
_________ and __________ affect hair growth
Nutrition and hormones
Follicles cycle between ________ and _________ phases
Active and regressive
Average ___________ growth per week
2.25 mm
Lose _____ scalp hairs daily
90
In women, ________ and ________ glands produce small amounts of ___________, but tumors on these organs can cause abnormally large amounts of androgens.
Ovaries and adrenal
Androgens
Can result in excessive hairiness called . . .
Hirsutism
Alopecia
Hair thinning in both sexes after age 40
Baldness
Genetically determined and sex-influenced condition
Male pattern baldness caused by . . .
Follicular response to DHT
Telegenic effluvium is __________ caused by ________________
Abrupt hair thinning
An abundance of hair follicles entering resting phase at same time
Telegenic effluvium can be due to . . .
Stress-induced factors such as: hormonal changes, surgery, severe emotional trauma or crash dieting
What is one major function of arrector pili muscle contraction that is particularly important in nonhuman mammals?
a) The arrector pili muscle contracts to allow for hair growth.
b) The arrector pili muscle contracts to shed dead hairs.
c) The arrector pili muscle contracts to alarm an approaching predator.
d) All of the above are true.
c) The arrector pili muscle contracts to alarm an approaching predator.
A female patient with excessive facial hair growth may have which of the following ailments?
a) Excessive estrogen secretion from the ovaries
b) Inadequate secretion of insulin from the pancreas
c) Inadequate secretion of thyroid hormone from the thyroid gland
d) Excessive secretion of androgens from an adrenal tumor
d) Excessive secretion of androgens from an adrenal tumor
