1. The Integumentary System Chapter 4

2. Integumentary System ZStructure Z Epidermis Z Dermis Z Subcutaneous ZFunctions of the skin

3. The “Birthday Suit” ZCombination of 4 main tissues Z Epithelial – outer layer Z Connective – underlies & connects dermis Z Smooth Muscle – erect hair Z Nervous – sensory receptors Z Structure allows it to carry out many functions ZProtection, hydration, sensation, color, temperature regulation, etc. ZVery durable

4. Functions of the Skin ZProtection ZTemperature regulation ZSensations ZStorage of chemical compounds Z Excretion of wastes Z Synthesis of compounds ZDetermines characteristics

5. Structure of the Skin Z2 principal parts Z Epidermis Z Dermis ZBeneath the Dermis Z Subcutaneous

6. Epidermis Z Stratified squamous epithelium ZApproximately every month we shed entire skin surface ZConsists of keratinocytes

7. Layers of the Epidermis (bottom to top) Z Stratum Germinativum ZCuboidal cells ZMitosis occurs Z Stratum Spinosum ZGerminal cells shrink ZCells look spiny Z Stratum Granulosum ZProduces keratohyaline & keratin ZCells die Z Stratum Lucidum ZFound only in thick skinned or calyces areas (hands, feet, elbows, knees) Z“Clear layer” ZFilled with keratin Z Stratum Corneum ZMultiple dead layers Z“ Cornified ” ZWaterproof

8. Layers of the Epidermis

9. Variations in Skin Color ZPigments Z Melanin ZProduced by melanocytes ZProtects skin from UV rays Z Carotene Z Red pigment of “gingers” ZLack of pigment Z Albino ZDermal blood supply Z “Blushing”

10. Epidermis & Dermis ZEpidermis is avascular (contains no vessels) ZDermis is highly vascular (contains blood vessels) ZEpidermis receives nourishment from dermis ZCells furthest away from nourishment die

11. Dermal Layer Z2 layers Z Papillary layer Z Reticular layer Connective tissue ZLoose Fibrous (collagen firm & elastic) ZAdipose ZContains ZBlood vessels ZNerves ZGlands Z Hair follicles

12. Papillary Layer ZMost superficial layer ZLoose connective tissue ZSurface area increased by papillae ZForm fingerprints for grip

13. Reticular Layer Deeper layer ZDense, irregular connective tissue (collagen) ZContains ZBlood vessels ZGlands Z Deep pressure receptors

14. Subcutaneous Layer ZLoose connective tissue ZPacked with adipocytes (fat cells) ZStabilizes position of skin, shock absorber, energy storage/source

15. Epidermal Appendages Z Hair Z Glands Z Nails

16. Hair (Pili) ZCame with mammals ZEmbryological development & distribution ZLife span of hair ZWhat does hair do for mammals?

17. Functions of Hair ZProtection Z Thermoregulation ZSensory ZMinor? role in humans Zbeauty

18. Hair Structure Z Shaft ZSuperficial Z Root ZBelow surface

19. Hair Structure Z Medulla ZSoft core Z Cortex ZHard core ZGives hair stiffness Z Cuticle ZOutermost layer

20. Hair Develops in Follicles ZLocation ZDeep in dermis ZStructure Z External root sheath Z Internal root sheath Z Bulb ZContains matrix Z Hair papilla ZContains blood vessels and nerves http://www.tgfolk.net/sites/gtg/tfb-elect.html

21. Arrector Pili ZSmooth muscle attaches to follicle ZRaises hairs ZEmotional response, cold ZFunction- traps air

22. Glands Z Sebaceous glands ZConnected to hair follicles ZSecrete a waxy, oily substance ( sebum ) ZDevelop in utero at about 5 months ZSecretion increases at puberty

23. Glands Z Sweat glands Z Eccrine glands ZFound just about everywhere (esp. palms & soles) ZProduce “ perspiration ” ZWater, salt, met. wastes http://www.pg.com/science/skincare/Skin_tws_35.htm

24. Glands Z Sweat glands ( scent glands ) ZCalled Apocrine sweat glands ZSpecific type of sweat gland ZFound near hair follicles Z Axillary & genital regions ZDevelop at puberty http://www.pg.com/science/skincare/Skin_tws_35.htm

25. The Skin with Sweat Glands

26. Nails ZDorsal surfaces of ends of fingers & toes ZPrimate feature ZGrasping

27. Nail Structure Z Nail body Z Free edge Z Nail root ZMatrix Z Lunula (moon)

28. Skin Cancer- Melanoma Squamous Cell Carcinoma Basal Cell Carcinoma