1. THE INTEGUMENTARY SYSTEM Skin and its Derivatives

2. TYPES OF MEMBRANES Epithelial + Connective Tissue  Serous  Cutaneous  Mucous Connective Tissue  Synovial

3. Serous Membranes Line body cavities that have no openings to outside. Secrete watery fluid. Simple squamous epith + loose CT

4. Mucous Membranes Line cavities that lead to outside. Secrete mucus for protection. Epithelium + Loose CT

5. Serous, Mucous Membranes

6. Synovial Membrane Lines joint cavities at articulations. Loose CT + elastic fibers + adipose tissue

7. Cutaneous Membrane Stratified squamous epithelium + CT + muscle + nervous tissue

8. Functions of Skin Protects from injuries Acts as barrier and regulates what enters/leaves body. Regulates body temperature. Synthesizes, stores vitamins. Sensory functions

9. EPIDERMIS Stratum corneum Stratum granulosum Stratum spinosum Stratum basale (germinativum) Stratum lucidum** **Thick skin only

10. Stratum Basale Lowest epidermal layer, near dermis Good nutrient supply Reproduces by mitosis Cuboidal, columnar in shape Moves to upper epidermis in 27 days.

11. Stratum Basale

12. Stratum Spinosum Living cells Dividing 8-10 cells thick Polygonal in appearance

13. Stratum Spinosum

14. Stratus Granulosum, Lucidum Poor nutrient supply. Flatten layer of cells. 3-5 cells thick. No cell division. Keratin accumulates. Found only in very thick skin. Translucent. Highly keratinized. Dead cells

15. Stratum Corneum 25-30 cells thick. Cells are filled with keratin and hardened. Sloughed off. Outer most layer of epidermis. Keratinocytes

16. Anatomy A215: EPIDERMIS LAYERS Memory Matrix Layer Superficial or Deep Layer? Characteristics Are cells keratinized in this layer? Seen in THIN skin too? Stratum Basale Stratum Spinosum Stratum Granulosum Stratum Lucidum Stratum Corneum

17. DERMIS Irregular Dense Connective Tissue Collagenous fibers

18. Dermis Sweat gland Sebaceous gland Arrector pili muscle Blood vessels

19. Hair Follicle

20. Sebaceous Gland Exocrine gland Associated with follicle Secretes oily substance Holocrine gland

21. Sebaceous Gland

22. Hair Follicles

23. Sweat Gland Exocrine gland Sudoriferous glands Produces water, salts Eccrine glands respond to temperature Apocrine glands respond to pain, emotions

24. Sweat Gland

25. Sweat Gland Exiting the Skin

26. Eccrine Gland

27. Types of Sweat Glands (Sudoriferous Glands) Merocrine glands: release fluid by exocytosis Eccrine –Most common –Secretion is mostly water with solutes –Cools body down Apocrine –Develops scent as bacteria metabolize secretion –Stimulated when frightened, during pain, during emotional upset

28. Hypodermis (Subcutaneous) Atlas of Human Anatomy in Cross Section: Section 2. Neck, Shoulders, Upper Arm, and Upper Thorax (Lungs) Key Figure 4 a Ronald A. Bergman, Ph.D., Adel K. Afifi, M.D., Jean J. Jew, M.D., and Paul C. Reimann, B.S. Peer Review Status: Externally Peer Reviewed Recognized by adipose tissue.

29. Sensory Structures of Dermis Deep touch/pressure: Pacinian corpuscles Light touch/pressure: Meisner’s corpuscles Warm temperature: Free nerve endings Cold temperature: Free nerve endings Pain: Free nerve endings

30. Melanocyte

31. Produces melanin for protection from UV radiation. Responsible for skin color. Melanoma.

32. Melanoma

33. Basal Cell Carcinoma

34. Untreated…..

35. Actinic Keratosis Caused by sun damage. Can lead to squamous cell carcinoma.

36. PSORIASIS

37. MAP SHOWING SKIN COLOR DISTRIBUTION

38. EVOLUTION OF SKIN COLOR Balance between –Need for protection against UV radiation which Causes skin cancer Destroys folate (vitamin B) –Need for UV to produce vitamin D for calcium absorption