6.2 accessory structures of the skin- anatomy

accessory structures examples

hear follicles, skin glands, nails

nails

protective ends of fingers and toes

nail plate

overlies a surface of skin called the nail bed

lunula

whitish half moon, at base of nail plate, most active growing site

hair is not located on the

palms, soles, lips, nipples, external reproductive organs

_____ percent of hair is in the growth phase

90%

hair follicle

tubelike depression, where hair originates from

hair bulge

bottom of hair follicle, stem cells originate here

hair root

contained in hair follicle

hair bulb

location of epidermal cells

hair shaft

extends away from skin surface

loses ______ hairs per day

100

Genes determine hair color by

directing the type and amount of pigment that epidermal melanocytes produce

eumelanin

Dark hair has more of the brownish-black

pheomelanin

blonde hair and red hair have more of the reddish-yellow

arrector pili muscle

attaches to each hair follicle, muscle contracts a short hair in the follicle stands on end, goose bumps

Sebaceous glands produce

globules of a fatty material that accumulate, swelling and bursting the cells, sebum

sebum composition

mixture of fatty material and cellular debris

sebum function

secreted into hair follicles through short ducts and helps keep the hairs and the skin soft, pliable, and waterproof

excess sebum causes

acne

sebaceous gland location

scattered throughout the skin but are not on the palms and soles

_______ opens directly to surface of the skin rather than being connected to hair follicles

lips, the corners of the mouth, and parts of the external reproductive organs

sweat gland composition

tiny tube that originates as a ball-shaped coil that is closed at its deep end, lined with sweat-secreting epithelial cells

sweat gland originates at

deeper dermis or superficial subcutaneous layer

merocrine sweat gland function

respond to elevated temp by heat or exercise, lower body temp

merocrine sweat gland location

forehead, neck, and back

pore

duct that opens at the surface, carries merocrine gland sweat

sweat composition

water, salt, wastes such as urea and uric acid

Apocrine sweat glands function

scent as skin bacteria metabolize them, body odor

Apocrine sweat glands become active during

puberty, frightened/upset/pain, sexual arousal

Apocrine sweat glands location

axillary regions and groin

Apocrine sweat glands open into

hair follicles