1. 5-1 Chapter 5 The Integumentary System Skin and its accessory structures –structure –function –growth and repair –development –aging –disorders

2. 5-2 General Anatomy A large organ composed of all 4 tissue types 22 square feet 1-2 mm thick Weight 10 lbs.

3. 5-3 Function of Integumentary system 4 functions:

4. 5-4 Focus on Homeostasis What happens to a burn patient

5. 5-5 Overview 2 Major layers of skin –epidermis is epithelial tissue only –dermis is layer of connective tissue, nerve & muscle Subcutaneous tissue (subQ or hypodermis) is layer of adipose & areolar tissue –subQ = subcutaneous injection –intradermal = within the skin layer

6. 5-6 Membranes Epithelial layer sitting on a thin layer of connective tissue (lamina propria) Types of membranes –mucous membrane –serous membrane –synovial membrane –cutaneous membrane (skin)

7. 5-7 Mucous Membranes Lines a body cavity that opens to the outside – mouth, vagina, anus etc Epithelial cells form a barrier to microbes Tight junctions between cells Mucous is secreted from underlying glands to keep surface moist

8. 5-8 Serous Membranes Simple squamous cells overlying loose CT layer Squamous cells secrete slippery fluid Lines a body cavity that does not open to the outside such as chest or abdominal cavity Examples –pleura, peritoneum and pericardium –membrane on walls of cavity = parietal layer –membrane over organs in cavity = visceral layer

9. 5-9 Synovial Membranes Line joint cavities of all freely movable joints No epithelial cells---just special cells that secrete slippery fluid

10. 5-10 Overview of Epidermis Stratified squamous epithelium Contains no blood vessels 4 types of cells 5 distinct strata (layers) of cells

11. 5-11 Cell types of the Epidermis Keratinocytes--90% –produce keratin Melanocytes-----8 % –produces melanin pigment –melanin transferred to other cells with long cell processes Langerhan cells –from bone marrow –provide immunity Merkel cells –in deepest layer –form touch receptor with sensory neuron

12. 5-12 Dermis Connective tissue layer composed of collagen & elastic fibers, fibroblasts, macrophages & fat cells Contains hair follicles, glands, nerves & blood vessels Major regions of dermis(FYI) –papillary region –reticular region

13. 5-13 Skin Color Pigments (1) Melanin produced in epidermis by melanocytes –same number of melanocytes in everyone, but differing amounts of pigment produced –results vary from yellow to tan to black color –melanocytes convert tyrosine to melanin UV in sunlight increases melanin production Clinical observations –freckles or liver spots = melanocytes in a patch –albinism = inherited lack of tyrosinase; no pigment –vitiligo = autoimmune loss of melanocytes in areas of the skin produces white patches

14. 5-14 Accessory Structures of Skin Epidermal derivatives Cells sink inward during development to form: –hair –oil glands –sweat glands –nails

15. 5-15 Structure of Hair Shaft -- visible Root -- below the surface Follicle surrounds root –external root sheath –internal root sheath –base of follicle is bulb blood vessels germinal cell layer

16. 5-16 Hair Color Result of melanin produced in melanocytes in hair bulb Dark hair contains true melanin Blond and red hair contain melanin with iron and sulfur added Graying hair is result of decline in melanin production White hair has air bubbles in the medullary shaft

17. 5-17 Functions of Hair P revents heat loss Decreases sunburn Eyelashes help protect eyes Touch receptors (hair root plexus) senses light touch

18. 5-18 Glands of the Skin Specialized exocrine glands found in dermis Sebaceous (oil) glands Sudiferous (sweat) glands Ceruminous (wax) glands Mammary (milk) glands

19. 5-19 Sebaceous (oil) glands Secretory portion in the dermis Most open onto hair shafts Sebum –combination of cholesterol, proteins, fats & salts –keeps hair and skin from soft & pliable –inhibits growth of bacteria & fungi(ringworm) Acne –bacterial inflammation of glands –secretions stimulated by hormones at puberty

20. 5-20 Sudoriferous (sweat) glands Eccrine (sweat) glands –most areas of skin –secretory portion in dermis with duct to surface –regulate body temperature with perspiration Apocrine (sweat) glands –armpit and pubic region –secretory portion in dermis with duct that opens onto hair follicle –secretions more viscous

21. 5-21 Burns Tissue damage caused by excessive heat, electrical,radioactive or chemical substances Destroys skin cells 1 st degree –sunburn(epidermis) 2 nd degree-blisters (epiderm, dermis) 3 rd degree- full thickness- all three layers (epi, dermis and sub cut)

22. 5-22

23. 5-23

24. 5-24 Homework –chapter 5 Wordbytes A1 (diagram), A2,A4,A5,A6,A13 B2, B8,B9, C1,C2,C3,C4 Focus on Homeostasis, pg, 167 Look up the disease Systemic lupus erythematosus in your text. What happens in this disease?