5-8

Sebaceous Glands ___________ glands ________________________ glands that discharge an oily lipid secretion into hair follicles Simple branched alveolar glands- communicate with a single follicle and share a duct Produce large quantities of lipids as they mature Released through holocrine secretion- rupture of secretory cells

Lipids Enter the _________________ of the glands ____________________________ muscles squeeze the sebaceous gland and force the lipids into the hair follicle and surface of skin _______________- secreted lipid; mix of triglycerides, cholesterol, proteins and electrolytes Inhibits growth of bacteria, lubricates and protects keratin of hair shaft, and conditions surrounding skin

Sebaceous Follicles Glands not associated with hair follicles ________________ discharge _______________ directly onto epidermis Located on face, back, chest, nipples and external genitalia

Sweat Glands

Apocrine Sweat Glands Armpits, around nipples, and in pubic region Secrete products into _____________________________ Coiled, tubular Produce a sticky, cloudy, and potentially odorous secretion Rely on _______________________ secretion Begin secreting at puberty Sweat produced is a nutrient source for bacteria Myoepithelial cells surround the secretory cells and contract and squeeze the gland Controlled by _____________________ system and circulating hormones

Merocrine (eccrine) Sweat Glands Coiled, tubular Discharge secretions directly onto surface of skin Adults have 2-5 million – __________________ and ____________ have the most ____________________ perspiration 99% H2O

Functions of Merocrine Glands Cooling surface of skin to reduce body temp- ___________________ perspiration Excreting water and _________________________ Providing protection from environmental hazards by discouraging MO growth Flushing them from surface or making difficult for them to adhere _____________________- peptide with antibiotic properties

Other Glands _______________________- interaction b/t sex hormones and pituitary hormones control secretion ______________________- passageway of external ear Secretions combine with nearby secretion glands to form cerumen

Control of Gland Secretions ANS controls sebaceous and ____________________ sweat glands Commands affect all glands of that type ________________________ glands are more precisely controlled

5-9

Nails Protect exposed ________________ surfaces of tips of fingers and toes Help limit distortion of digits when subjected to mechanical stress

Parts of Nails _____________________- visible portion; covers nail bed Dead, tightly compressed cells packed with keratin Nail bed- recessed deep to level of surrounding epithelium Bound on either side by lateral nail grooves and nail folds _____________________- distal portion that continues past nail bed _____________________________- area of thickened stratum corneum free edge extends over

Parts of Nail Nail root- where nail production occurs Deepest portion lies close to bone __________________________- cuticle; portion of stratum corneum of nail root that extends over exposed nail ____________________- pale crescent; caused by vessels being obscured

5-10 Regeneration of Skin

Step 1 Damage extends through ________________ and into ______________ Bleeding occurs

Step 2 Blood clots or scab forms at surface and restricts entry of MOs Bulk of clot consists of ________________- protein that forms from blood proteins Clot’s color reflects presence of trapped ________________ Cells of stratum germinativum undergo rapid divisions and migrate along edges of wound ________________________ remove debris and pathogens

Step 3 ______________________________-blood clot, fibroblasts, and extensive capillary network Over time, deeper portions of clot dissolves ________________________ activity leads to appearance of collagen fibers and ground substance

Step 4 __________________ contains abnormally large # of collagen fibers and few blood vessels Hair follicles, glands, and nerves are replaced by ________________ tissue Formation of scar tissue completes repair process

Keloid _______________ tissue formation that continues beyond requirements of tissue repair Thick, raised area of scar tissue Covered by shiny, smooth epidermal surface Upper back, _____________________, anterior chest, and earlobes

5-11

Aging ______________________ thins; connection b/t epidermis and dermis weakens # of Langerhans cells decreases- reduces sensitivity of immune system Vitamin D3 production declines by 75%-reduced calcium and phosphate absorption _______________________ activity declines

Aging cont _______________________ activity declines- skin dry and scaly Blood supply to dermis reduced- skin cool Hair follicles stop functioning or produce thinner, finer hairs Dermis thins and elastic fiber network decreases in size Secondary sexual characteristics in hair and body-fat distribution fade Skin repairs ______________