 Largest _________ (21 ft 2 in adult, weighs about 8 lbs)  Usually attaches to _________ (exception: flexion creases)  Thinnest layer? (0.5mm) _______________ Thickest layer? (4.0mm) _________________  Why a system?

 Epidermis – stratified ____________; stratum basale (cell __________); stratum corneum (keratinized); Langerhans cells (___________ cells, APCs); melanocytes (roughly ________ # in everyone)  Dermis – loose and ___________connective; dermal papillae  epidermal ridges (f_______, surface area); elastin/collagen; blood vessels; receptors for t______, pr________, p_______, and temp.; hair ____________; sweat glands; sebaceous glands (produce _________)  Subcutaneous (Hypodermis) – loose connective and ____________ (insulates; excessive amounts = obesity)

Notice all of the bacteria. Stratum corneum. Notice how the squamous cells form a protective scale-like layer (~15-20 cells thick).

 Develops from hair ___________ (cuticle cells of hair and cuticle cells of follicle grow in __________ directions – keeps hair from _________ _______)  Three phases of hair follicle cycling:  Anagen – growth (2-8 years; genetically determined)  Catagen – transition (2-3 weeks; end of ______; cut off from ___________ supply)  Telogen – rest (about 3 months, then hair _______ out; about shed/day)  As the hair grows, __________ digest sheath around hair shaft at skin’s surface  Sebaceous gland and arrector ______

Hair Notice how the cells grow in opposite directions. Hair MagnifiedHair Magnified (3:12)

 Color of hair is controlled and affected by ________.  Albinism is a genetic ___________ that prevents the production of _____________ within melanocytes.

 Nails – nail root; nail bed; nail body (plate); lunula; cuticle; made mostly of k_____________ cells; grow __________ on the hand you use – Why?  Condition of nails can provide clues to underlying ____________ (color, shape, presence of lines on nail body)  What’s the cause of the white spots? Should we worry about them? Will they kill us?!?!

 Sweat glands – most concentrated on ____________ (Why?); apocrine (empty into _______ _________); eccrine (empty onto ________ ____________); ceruminous glands (cerumen, wet/dry); mammary glands (modified sweat glands that secrete __________)

 Protection from physical ____________  Protection from ___________ invasion  Prevents __________ loss/gain  Synthesis of vitamin ____ (in presence of light)  Regulation of body __________________

 Heat arises from breakdown of _______ose and ATP (heat is absorbed by __________); vasodilation; vasoconstriction; sweating; contraction of _____________ pili; hyperthermia; hypothermia; fever – benefits?

 Athlete’s foot: _________ infection  Impetigo: ____________ infection; usually S. aureus  Furuncles/carbuncles: inflammation of hair ____________ and ________________ glands; ______________ infection; can become severe in people with d___________; S. aureus  Eczema/psoriasis: overactive ______ ___________  Dandruff: increased keratinization  Urticaria: hives; ______________ reaction  How to become a dermatologist (3:36) How to become a dermatologist

Athlete’s Foot (fungal infection) Impetigo (bacterial infection) Carbuncle in diabetic (bacterial)Furuncle/boil (bacterial)

Urticaria/hives (allergic reaction) Eczema (overactive cell division; skin irritant) Psoriasis (overactive cell division; genetic)

 Melanoma – due to _____; malignant; cancer of ____________; arises from _________; ~8000 deaths per year in US, ~50,000 worldwide  Basal cell carcinoma – due to _____; ___________ tumor in basal cells of epidermis  Squamous cell carcinoma – due to _____; usually ___________; found in ____________ cells of epidermis  Moles – benign overgrowth of melanocytes  Warts – not tumors; _________ infection (HPV: human papillomaviruses - nearly 200 of them; a few are oncoviruses)  Treeman (7:31) Treeman after surgery (1:53)TreemanTreeman after surgery (1:53)

Melanoma on Skin Melanoma on the iris Basal Cell CarcinomaSquamous Cell Carcinoma Melanoma AnimationMelanoma Animation (3:01) Melanoma Video Melanoma Video (5:04)

Photos courtesy of Josie Harrington, former student

 1 st, 2 nd, 3 rd, and 4 th degree 1 st degree 2 nd degree 3 rd degree

 Rule of nines  Used to determine the _________ of a burn  Expressed in _____  What is its purpose?

 wound  clot  scab  WBC work  fibroblasts make new tissue  scar Benefits of a wound-healing medication Wound Healing Process (4:06) How wounds heal (4:00)

 Dermis thins; epidermis becomes _________; less ___________ in subcutaneous; less collagen and elastin (reduced flexibility); difficulty maintaining temp. _______________; fewer hair __________; less sebaceous glands (cracking due to less __________); fewer ______________ (blotchy pigmentation); gray hair – Why? Age spots (UV damage) Meet Mrs. Tinker!