Contraction of arrector pili stimulates causes sebaceous glands to secrete

Contraction of arrector pili stimulates causes

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Contraction of arrector pili stimulates causes sebaceous glands to secrete sebum Sebaceous follicles: discharge sebum directly onto skin of face, back, nipples, and external genitalia (large sebaceous glands) Sweat glands (Sudoriferous glands): apocrine sweat glands and merocrine sweat glands 1. Apocrine sweat glands a. Become active in puberty, and secrete into hair follicles in armpits, around nipples, and in public region b. Secretion is sticky, cloudy, and potentially odorous c. Sweat is a food source for bacteria on skin so this increases the odor RELY ON MEROCRINE SECRETION 2. Merocrine Sweat glands (eccrine sweat glands) a. Use merocrine secretion b. Coiled tubular glands secrete watery perspiration (sweat) directly onto the skin’s surface c. Very numerous, high numbers on soles and palms d. Sweat is 99% water with electrolytes, urea, and organic nutrients (sodium chloride gives it the salty taste) e. Function is to cool body through evaporation 3. Modified sweat glands a. Mammary glands: structurally related to apocrine sweat glands/ secrete milk, apocrine secretion b. Ceruminous glands: located in passageway of external ear/ secretions combine with sebaceous gland secretions to form cerumen (earwax), apocrine secretion Nails Protect dorsal surfaces of tips of fingers and toes Nail body (visible) is made of dense, keratinized cells, recessed beneath surrounding epithelium and bordered by lateral nail folds Nail bed the deeper level of epidermis covered by the nail body Nail root epithelial fold not visible from the surface, this is the site of nail production and is covered by the cuticle or eponychium (portion of the stratum corneum) Lunula pale crescent near nail root
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Lecture Notes Book Notes Slides 43 Repair of the Integument Skin regeneration occurs because: Stem cells of epithelium and connective tissues undergo cell division, replacing lost or damaged tissue Four phases of skin regeneration: 1. Inflammatory phase a. Result is increased blood flow to region and increased numbers of phagocytes b. Bleeding occurs immediately and the mast cells trigger an inflammatory response 2. Migratory phase a. After several hours, a scab has formed and the cells of the stratum basale are migrating along the edges of the wound b. Phagocytic cells remove debris c. Circulation is enhanced in the area and clotting occurs to isolate the region d. If the wound covers extensive area or involves a region of thin skin: granulation tissue forms in deeper tissue (combination of blood clot, fibroblasts, and extensive capillary network) 3. Proliferation phase a. Deeper parts of the clot dissolve b. Number of capillaries decline c. Fibroblasts form extensive meshwork of collagen fibers d. Week after injury the scab is undermined by epidermal cells 4. Scarring phase a. Fibroblasts continue to create fibrous, noncellular scar tissue to elevate epidermis b. After several weeks the scab is shed and the epidermis is complete c. Scar tissue is still made d. Degree of scar formation dependent on severity and location of injury and age of
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