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