dermis & accessory structures ( hair, glands, nails)
TRANSCRIPT
Dermis & Accessory Structures (Hair, Glands, Nails)
Dermis
Beneath epidermis The location for blood vessels, nerves, glands,
hair follicles, and arrector pili (smooth muscle; contractions produce “goose bumps”)
Fig. 5.2
Dermis - Structure Papillary region - upper
layer - 20% Areolar connective tissue
Reticular region - 80% Underneath the papillary
layer Dense irregular connective
tissue Fibers tolerate limited
stretching; “stretch marks” can appear
Hair
Functions: Protection Insulation Sensation Secondary sexual characteristic to attract mates
Hair Cont.Hair Follicle – site of hair
origin
Hair: Shaft (above skin surface) Root & bulb (underneath skin
surface) Bulb contains matrix –
dividing layer; builds hair Hair is made out of keratin
Nails
tightly packed, hard, keratinized cells
nail matrix - site of nail growth; under root of nail
Sebaceous (Oil) Glands connected to hair
follicles in the dermis secrete sebum (oil)
keeps hair from drying prevents water
evaporation from skin keeps skin soft, supple inhibits growth of many
bacteria
busy at puberty
Sudoriferous (Sweat) Glands
Eccrine (merocrine) glands: In the skin that covers most parts of our bodies Produce a thin, watery liquid that contains salt and small amounts
of other bodily wastes Help cool the body through the process of evaporation
Apocrine glands: In the skin of the armpits, around nipples, and in the groin Produce a thicker salty and acidic solution Produce “body odor” (in contact with bacteria) Become active when a person reaches puberty Secrete more during emotional stress & sexual arousal
Apocrine & Eccrine Sweat Glands
Other Specialized Integumentary Glands
Ceruminous glands – together with oil glands produce ear wax
protect against foreign particles & small insects
Burns