Accessory Organs of the Skin

Hair Characteristics  Location: Almost everywhere (soles, palms, lips ect.)  Structure:  Hair follicle- organs producing hair, epidermal strata  Hair papilla- follicle base, CT, capillaries & nerves  Hair matrix- ET stem cells  Hair bulb- swelling of follicle, growth  Hair root-anchors hair into skin  Hair shaft- visible portion, dead, keratinized cells  Cuticle-outer  Medulla-middle  Cortex -inner

Hair Characteristics Cont. Growth:  Hair is produced in cycles-growth and rest phases  Typically grows 2-6 years (approximately 0.3 mm a day)  Typically rests 2-3 months  When new hair begins growing the older hair is pushed outward to drop off- we lose about 100 scalp hairs a day. Color:  Genes determine hair color by directing the type and amount of pigment the epidermal melanocytes produce. Texture:  Shape of the hair follicle will determine what texture the hair shaft is.

Hair Function  Protection  Cushion  Insulation

Nails  Location/Function: protective coverings on the ends of finger and toes  Structure:  Free edge-white portion of the nail that grows out from the finger or toe  Nail body (plate)-dead, keratinized epithelial cells  Nail bed-skin beneath nail plate  Nail root- growth site, deep to cuticle  Cuticle- extends over the exposed nail, protection  Lanula- pale crescent area

Nail Appearance  Health factors can be seen in nail appearance.  Bluish nails-reflect circulation problems  White nail bed or depressions-anemia, zinc or calcium definceny  Pigmented spot under nail-melanoma  Horizontal furrows-Malnutrition/illness  Extreme curvature-lung, heart or liver disorders  Red streaks-rheumatoid arthritis, ulcers or hypertension  Yellow-numerous disorders from AIDS-Bronchitis

Skin Glands- Exocrine glands 1. Sebaceous Glands - or oil glands, contain groups of specialized epithelial cells that are usually associated with hair follicles.  Holocrine glands  Cells produce globules of a fatty substance that accumulate, swelling and bursting the cells-the result is known as sebum.  Sebum is secreted into the hair follicles through short ducts to keep hair and skin soft, pliable and waterproof.  Acne results from excess sebum secretion  Found all throughout the skin except palms and soles.

Skin Glands Cont.  2. Sweat Glands -or sudoriferous glands are widespread in the skin.  Originates as ball-shaped coil in the deeper dermis or subcutaneous layer.  Eccrine (merocrine) Glands- most numerous sweat gland (2-5 million) that respond to body temperature by environmental heat or physical exercise  High amounts in palms/soles, forehead, neck and back  Discharge secretions directly onto the skins surface  Apocrine glands- secretions develop a scent as they are metabolized by skin bacteria.  Become active at puberty  Active when a person is upset, frightened, in pain or during sexual arousal  Common in the axillary region, groin, and around the nipples.  Open into hair follicles