1. The Integumentary System Chapter 36.3

2. Organs are two or more tissues which together perform a specialized function. Epithelial membranes are thin structures that usually contain both epithelial and connective tissue.

3. Mucous membranes –Line cavities that open to the exterior –Layer of epithelium over connective tissue; epithelium varies with location –Tight junctions and goblet cells Cutaneous membrane is the skin –the major organ of the integumentary system

4. Integumentary system is the skin and the organs derived from it (hair, glands, nails) One of the largest organs –2 square meters; 10-11 lbs. –Largest sense organ in the body The study of the skin is Dermatology

5. Functions: 1. Regulation of body temperature –Cellular metabolism produces heat as a waste product. –High temperature Dilate surface blood vessels Sweating –Low temperature Surface vessels constrict shivering

7. 2. Protection physical abrasion dehydration ultraviolet radiation 3. Sensation touch vibration pain temperature

8. 4. Excretion 5. Immunity/ Resistance 6. Blood Reservoir 8-10 % in a resting adult 7. Synthesis of vitamin D uv light aids absorption of calcium

9. Anatomy Epidermis Skin Dermis Subcutaneous layer or hypodermis

14. Dermis Connective tissue layer Collagen and elastic fibers, nerves, blood vessels, muscle fibers, adipose cells, hair follicles and glands.

15. Accessory organs or epidermal derivatives Hairs –Epidermal growths that function in protection –Shaft, root, and folllicle –Sebaceous glands, arrector pili muscle, and hair root plexus (touch) –Hair growth and replacement have a cyclical pattern –‘male-pattern’ baldness

16. Nails Plates of highly packed, keratinized cells Protection, scratching, & manipulation Formed by cells in nail bed called the matrix ( in area of lunula) 1 mm / week Eponychium - cuticle

19. Skin Glands Sebaceous (oil) glands –Usually connected to hair follicles –Holocrine glands –Fats, cholesterol, proteins, salts, and cell debris –Moistens hair and waterproofs skin

22. Skin color Genetic factors –Same number of melanocytes –Albinism Environmental factors –Uv light or x-rays

24. Wound healing Inflammation –Blood vessels dilate and become permeable Heat, redness, swelling and pain Shallow cuts –Epithelial cells migrate –Contact inhibition

26. Deeper wounds Inflammatory phase –Fibrin forms clot Migratory phase –Fibroblasts make granulation tissue Proliferative phase Maturation phase Scars – hypertrophic scar –keloid

31. Burns First degree or partial thickness burn –Only epidermis is damaged –Erythema, mild edema, surface layer shed –Healing – a few days to two weeks –No scarring

32. Second degree- deep partial-layer burn –Destroys epidermis –Blisters form –Healing depends on survival of accessory organs –No scars unless infected

33. Third degree or full-thickness burn –Destroys epidermis, dermis and accessory organs of the skin –Healing occurs from margins inward –Skin grafting may be needed Autograft Homograft Rule of Nines