2. Chapter 5-1 & 5-2 Integumentary system

3. Integumentary System 2 major components: ________________________ membrane Epidermis Dermis Accessory structures Hair _______________ Multicellular ______________________ glands

4. Functions of Skin and Hypodermis Protection- underlying tissues and organs ____________________- salts, H2O, and organic wastes by glands Maintenance- normal body temp Production- melanin and _________________ Synthesis of Vitamin D3 __________________- lipids in adipocytes Detection- touch, pressure, pain and temp

5. Epidermis Stratified squamous epithelium ____________________ Rely on diffusion of nutrients and O2 from capillaries within dermis Dominated by keratinocytes- from several layers Contain large amounts of keratin Thin skin- most of body surface (4 layers) ____________- palms of hands and soles of feet ( 5 layers)

6. Layers of Epidermis Stratum germinativum Stratum spinosum Stratum granulosum Stratus lucidum Straus corneum

7. Stratus Germinativum Innermost epidermal layer __________________________ attach cells of this layer to basal lamina Forms epidermal _________________- extend into dermis and are adjacent to dermal papillae Ridges on palms and soles increase surface area and increase friction Genetic and doesn’t change __________________ cells- main cells and replace lost superficial keratinocytes at surface

8. Stratum Spinosum Each time a stem cell divides, one of the daughter cells is pushed here 8-10 layers of keratinocytes bound by _____________________ Contains Langerhans (___________________) cells- participate in immune response

9. Stratum Granulosum 3-5 layers of keratinocytes derived from stratum spinosum Most cells have stopped dividing at this layer and started making large amounts of keratin and keratohyalin ___________________- tough fibrous protein; basic component of hair and nails

10. Stratum Lucidium Thick skin of palms and soles Cells filled with ________________

11. Stratum Corneum Exposed surface 15-30 layers of keratinized cells ___________________________- formation of protective, superficial layers of cells filled w/ keratin; all exposed surfaces except anterior of eyes Takes 15-30 days for a cell to move from stratum germinativum to stratum corneum

12. Stratum Corneum Water resistant but not waterproof Water from interstitial fluids slowly penetrates surface ____________________________________-unable to see or feel water loss; approx. 500 ml a day Sensible perspiration- produced by active ______________ glands

13. 5-2 Skin Color

14. Epidermal Pigmentation __________________- orange- yellow pigment Most apparent in cells of stratum corneum of light-skinned indiv. Also accumulates in fatty tissues in deep dermis and SQ layer Found in orange vegetables Can be converted to vitamin A

15. Epidermal Pigmentation ___________________- brown, yellow-brown, or black pigment Produced by ________________________- stratum germinativum Differences in skin pigmentation among indiv. do not reflect different # of melanocytes Represents different levels of synthetic activities Ex: albino indiv. Are distributed normally but cells are incapable of producing melanin

16. Freckles Small pigmented areas on skin Areas where _________________________ that produce larger amounts of melanocytes

17. Lentigos Similar to freckles Regular borders Contain abnormal ___________________________ Senile lentigos- ___________________________

18. Ultraviolet Radiation Small amount is beneficial Can damage DNA, cause mutations and promote development of cancer Over time, cumulative damage can harm ______________________ causing impaired maintenance of dermis- premature _____________________

19. Role of Dermal Circulation When bound to oxygen, hemoglobin is bright red, giving capillaries in the dermis a reddish tint When blood supply is temporarily reduced, skin becomes pale _____________________- bluish discoloration; O2 levels decline in tissues

20. ___________________________ Liver can’t excrete bile Yellowish pigment accumulates in body fluids Advances stages- whites of eyes and skin turn yellow

21. __________________ Individuals lose melanocytes Incidence increases among individuals with thyroid gland disorders