1. BODY MEMBRANES

2. EPITHELIAL MEMBRANES Cutaneous Mucous Serous

3. Cutaneous Membranes Skin Composed of two layers - Epidermis - Dermis = dense connective - Hypodermis (subcutaneous)= adipose layer under dermis; (not considered part of the skin)

5. Mucus membranes (mucosa) Moist, line cavities that open to the outside of body Most secrete mucus Rests on loose connective tissue membrane (lamina propria )

7. Serous membrane (serosa) lines cavities that do not open to the outside self-enclosed Inner space is filled with serous fluid Supports and allows movement of the organs in the cavity

8. Visceral serosa = side that contacts organs Parietal serosa = side attached to cavity wall

10. Serous Membranes Peritoneum: lining abdominal cavity and covering its organs Pleura: surrounds lungs Pericardium: surrounds heart

12. Synovial membranes Connective tissue membranes that cushion and lubricate bone movements Line and lubricate joint cavities (the space between bones) Composed of soft areolar tissue

14. FUNCTIONS OF SKIN Thermoregulation – heat loss/retention Excretion of urea and uric acid Synthesizes vitamin D – via sunlight Protection from: –Mechanical damage - UV radiation –Chemical damage-thermal damage –Bacteria- desiccation

15. The Structure of Skin

16. EPIDERMIS Keratinized stratified squamous epithelium (keratin fibers made from KERATINOCYTES) Composed of 5 layers called STRATA Avascular – shaving may not cause bleeding (unless you cut into dermal layer)

18. STRATA (deepest  superficial) 1.Stratum basale:  closest to dermis  the only epidermal cells that receive adequate nourishment via diffusion of nutrients from dermis  cells constantly undergoing mitosis  millions of cells produced daily  cells pushed upward toward surface

20. 2.Stratum spinosum - several layers of cells with large, oval centrally located nuclei and spiny processes - limited mitosis - most cells dying and being moved toward surface

21. 3. Stratum granulosum One or more layers of granular cells Shriveled nuclei Contains keratin

22. 4. Stratum lucidum Thin, clear layer No remaining living cells Present only in the thick skin of the palms and soles (hairless and extra thick skin)

24. 5. Stratum corneum 20 to 30 cell layers thick Outermost layer Cornified or horny cells (completely filled with keratin) Rubs and flakes off slowly and steadily Replaced by cells from stratum basale We have totally new epidermis every 25-45 days

27. Melanin Produced by melanocytes found in stratum basale Ranges in color from yellow to brown to black Sun stimulated melanocytes to produce melanin pigment: TANNING

30. TANNING Stratum basale cells phagocytize the pigment and it accumulates Forms protective ‘umbrella’ over superficial side of nuclei Shields DNA from UV radiation damage

31. Excessive Sun Exposure Causes elastic fibers to clump (leathery skin) Depresses immune system (people w/herpes are more likely to have eruption after sunbathing) Skin cancer

33. Go to: http://www.meddean.luc. edu/lumen/MedEd/Histo/ frames/h_fram13.htmlhttp://www.meddean.luc. edu/lumen/MedEd/Histo/ frames/h_fram13.html

34. Development of a scaffold for dermo-epidermal skin grafts  Hyaluronic acid  polysaccharide, main component of extracellular matrix of all connective tissue  particularly present in the dermis  involved in the processes of tissue repair.

35. Processable biomaterial, which may be transformed in several physical forms: -fibers -Membranes -Microspheres -Tridimensional matrices.

36. HYAFF ® Tridimensional matrix, utilized as scaffold to growth the cells of the skin in the laboratory.

37. Scanning electron microscope picture of the scaffold utilized to build the "bioengineered" skin.

38. Cells growing into the tridimensional structure of HYAFF ®. These cells are able to form new dermal tissue.

39. LASERSKIN ® : delivery system for the keratinocytes, the epidermal cells which form the external layer of the human skin.

40. Skin cells growing on the HYAFF ® membrane. Through the microperforations the cells are able to reach the wound bed and to regenerate the epidermis.

41. Application of the bioengineered skin on a foot ulcer