The Integumentary System

1. The skin and its accessory structures The Integumentary System

2. Protection Regulate body temperature Cutaneous sensation Synthsize Vitamin D Blood storage Excretion of wastes (sweat) Functions of the Integumentary System

3. The Skin • A large organ composed of all 4 tissue types • 22 square feet • 1-2 mm thick • Weight 10 lbs. dfasdjsdjfkjdfljlfjldfjlsdjlsflksdjsjfklsjfjdfjsdlfjsdfdlsfasdjlsflsdfljdlfsdfjsdkljdfasdklsdjsjfldjflasfjsfljjflasjlldjfla dfjkjklsjfksjfljdljdlfjklfj

4. The Integumentary System (www.medcomrn.com) (800) 877-1443.wmv video

5. Epidermis The superficial portion of the skin Composed of epithelial tissue Dermis The deeper layer of the skin Primarily composed of connective tissue Hypodermis (subcutaneous layer) Deep to the dermis Not a part of the skin Consists of areolar and adipose tissue Fat storage, area for blood vessel passage, and an area of pressure sensing nerve endings Layers of skin

6. Stratified squamous epithelium avascular (contains no blood vessels) 4 types of cells 5 distinct strata (layers) of cells Overview of Epidermis EPIDERMIS DERMIS

7. Keratinocytes • Produce keratin • KERATIN protects skin and underlying tissue from heat, microbes, chemicals • Release lamellar granules which release a lipid waterproof sealant Melanocytes • Produce pigment melanin • melanin contributes to skin color and absorbs damaging ultraviolet rays (UV rays) Langerhans cells • Phagocyte cells that participate in immune response Merkel cells • Sensory cells • Function in the sensation of touch Four principle cells of epidermis

8. From deepest to most superficial (bottom to top) • Stratum basale (also called stratum germinativum) • Stratum spinosum • Stratum granulosum • Stratum lucidum (only in palms and soles) • Stratum corneum 5 Layers of the epidermis

9. Stratum Basale(basal layer) • Deepest single layer of epidermis • Include all 4 cell types: merkel cells, melanocytes, keratinocytes & stem cells • Cells divide repeatedly (MITOSIS) • When this portion of the epidermis is destroyed, new skin cannot regenerate (even with a skin graft).

10. Stratum Spinosum(prickly layer) • Provides strength and flexibility to the skin • 8 to 10 cell layers

11. Stratum Granulosum(granular layer) • Transition between the deeper, metabolically active strata and the dead cells of the more superficial strata • 3-5 layers of flat dying cells that show nuclear degeneration • Contain lamellar granules that release lipid that repels water • Contain dark-staining keratohyalin granules • keratohyalin converts into keratin

12. Stratum Lucidum(clear layer) • Present only in the fingers tips, palms of the hands, and soles of the feet. • 3 to 5layers of clear, flat, dead cells • Contains precursor of keratin

13. Stratum Corneum(Horny layer) • 25 to 30 layers of flat dead cells filled with keratin and surrounded by lipids • Continuously shed • Barrier to light, heat, water, chemicals & bacteria • Lamellar granules in this layer make it water-repellent. • Where callus, an abnormal thickening of the epidermis, is formed

14. B S G L C Mneumonic device Every Good Boy Does Fine. Please Excuse My Dear Aunt Sally. King Philip, Come Out For Goodness Sake!

15. Skin Structure Figure 4.4

16. Melanin • Pigment (melanin) produced by melanocytes • Color is yellow to brown to black • Melanocytes are mostly in the stratum basale • Amount of melanin produced depends upon genetics and exposure to sunlight • Skin with too much melanin is called hyperpigmented skin. • Skin with too little melanin is called hypopigmented skin.

17. Strong, flexible connective tissue Heavily embedded with collagen, elastin, reticular fibers Binds the entire body together like a body stocking. (Like an animal “hide”.) Richly supplied with nerve fibers, blood vessels, and lymphatic vessels. Contain: hair follicles, oil & sweat glands DERMIS

18. Dermis • Two layers 1. Papillary layer (thin, superficial layer = 20%) • Projections called dermal papillae • Pain receptors • Capillary loops • epidermal ridges form on palms of hands and soles of feet • increase friction and enhance gripping • Form FINGERPRINTS

19. (80% thickness) • Contain; blood vessels, glands, nerve receptors • Bundles of collagen fibers form cleavage lines (Appear as fine lines on the skin.) • Surgery: incisions parallel, not perpendicular • No skin gapes; heals faster • Collagen & Elastin: give skin resiliency, flexibility and bind to water to keep skin hydrated. • Flexure lines (deep folds) @ joints (wrists, fingers, soles, toes) 2. Reticular layer

20. There are three basic fingerprint patterns and seven subgroups. FINGERPRINTS

21.  A fingerprint is an impression of the friction ridges found on the inner surface of a finger or a thumb. Friction ridges are also found on the palms of the hands and on the soles and toes of your feet. Fingerprints are formed while a baby is still in the womb. You cannot get rid of your fingerprints – you also cannot change them, unless you do something drastic such as chopping off a finger. FINGERPRINTS

22. Every person’s fingerprint is unique. Not even identical twins have the same fingerprints. No two fingerprints have ever been found to be identical. Secretions from the eccrine (sweat) glands can leave impressions on smooth surfaces, such as glass, plastic, and polished wood. A special type of powder is used to ‘lift’ fingerprints from such surfaces for purposes of identification. FINGERPRINTS

23. A Frenchman, pioneered the use of physical evidence to solve crimes. The date was 1812. Fingerprinting is the most commonly used forensic evidence worldwide. It is claimed to do better than DNA testing to identify murderers, rapists and other serious offenders, especially in countries where DNA testing is not widely used. FINGERPRINTS

24. tattoos

25. tattoos

26. Tattooing is a permanent coloration of the skin in which a foreign pigment is injected into the dermis. When first injected into the skin, tattoo ink spreads from the puncture site to both the epidermis and the dermis. And as your tattoo heals, immune cells or phagocytes in the epidermis engulf the ink and epidermal cells flake off, carrying ink away. The dermis also contains cells involved in immune responses and that recognize the tattoo ink as foreign. Tattoo ink is trapped in the dermis in a meshwork of fibroblast cells and collagen that form granular tissue. If a tattoo is done properly, tattoo ink won't reach the hypodermis. As you get much older, the tattoo pigment may migrate deeper into the dermis (that's why your tattoo may fade a bit over time), but for the most part, it remains at the upper portion of the dermis, closer to the epidermis. tatToos

27. Melanin • Yellow, brown or black pigments • Carotene • Orange-yellow pigment from some vegetables • Hemoglobin • Red coloring from blood cells in dermis capillaries • Oxygen content determines the extent of red coloring Skin color

28. Go to page 156 in your text. • Choose ONE homeostatic imbalance on page. • Read about it. • Write a short summary in your notebook, identifying the name, cause, and appearance (if listed). Homeostatic imbalances