integumentary system.pptx. .

Anatomy

1. Integumentary System

2. Integumentary System Skin Epidermis Dermis Accessory structures (appendages) Glands Hair Nails

3. Epidermis Outermost layer of the skin Comprised of epithelial cells Contains no blood vessels (avascular) Nutrients diffuse over from dermal blood vessels Is thicker in areas of significant wear and tear (palms of hands and soles of feet) Keratin Protein that replaces epidermal cell cytoplasm in order to thicken and protect the skin Also comprises hair and nails

4. Epidermis – Thick vs. Thin Skin Thick Skin (aka, glabrous [hairless] skin) 5 layers Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale (stratum germinativum) Thin Skin (aka, vellus [hairy] skin) 4 layers (stratum lucidum is absent and stratum corneum is much thinner)

5. Dermis SB SS SG SL SC

6. Epidermis Thick Skin Thin Skin

7. Epidermal Cells Keratinocytes Major epidermal cell type ~28 day transit time from stratum basale to stratum corneum Melanocytes Scattered between cells of stratum basale Contain organelles called melanosomes , in which the melanin pigment is synthesized Melanosomes are quickly released and phagocytized by neighboring keratinocytes (epidermal melanocytes do not retain their melanosomes ) Langerhans cell – involved in immune response Merkel cell – touch receptor

8. Epidermal Cells Melanocyte Keratinocytes

9. Melanin in Stratum Basale Keratinocytes

10. Dermis Comprised of elastic connective tissue Allows for skin to stretch Contains blood vessels (vascular) and nerves (innervated) Location of accessory structures (sweat glands, oil glands, and hair) Dermal papillae Extensions of dermis into epidermal layer Are what form fingerprints

11. Dermis

12. Dermal Papillae

13. Hypodermis aka, subcutaneous layer NOT part of the skin Connects skin to surface muscles Consists of loose connective tissue and fat (adipose) tissue

14. Burns 1 st Degree (aka, superficial partial-thickness) Epidermis and possibly a portion of dermis Tissue is reddened and may blister 2 nd Degree (aka, deep partial-thickness) Epidermis and portions of dermis Tissue is blistered and broken 3 rd Degree (aka, full-thickness) Full skin and possibly subcutaneous tissue Tissue is broken, dry and pale, or charred Rule of Nines – estimate % of body surface area in treatment of burns

15. Accessory Structures (appendages) Glands Sebaceous (Oil) Sudoriferous (Sweat) Eccrine Apocrine Hair Nails

16. Sebaceous (Oil) Glands Sebum – oily secretion Lubricates skin and coats hair Prevents drying It is believed that bacterial lipases break down triglycerides of sebum into irritative fatty acids that cause acne. Ducts open into hair follicles Meibomian glands Modified sebaceous glands Lubricate eyes

17. Questions to answer (place on separate paper and turn them in on the way out) 1) Why is a third degree burn so much more devastating than a first degree burn? (Answer based on the specific skin layers and structures involved.) 2) Why does washing your hair actually damage it? How do we treat this damage?

18. Sebaceous (Oil) Glands

19. Sudoriferous (Sweat) Glands Cool the body via evaporation Eccrine Sweat Glands Distributed over entire body except lips and parts of external genitalia Ducts open directly onto surface of skin Excrete salts, urea, ammonia, and uric acid along with water

20. Sudoriferous (Sweat) Glands (cont.) Apocrine Sweat Glands Located in armpits (axillae), nipples, and groin area Duct empties into hair follicle superficial to sebaceous gland Become active at puberty Secretion is initially odorless; bacteria on the skin metabolize secretory products to produce malodorous compounds Secrete in response to emotional stimuli (not heat) Modified apocrine sweat glands Ceruminous glands – ear canal; produce cerumen (ear wax) Ciliary glands - eyelids Mammary glands – produce milk (breasts)

21. Hair Two types in adults Vellus hairs – thin, short and poorly pigmented Terminal hairs – thicker, longer and more heavily pigmented Composed mainly of “hard keratin” (as opposed to “soft keratin” in the epidermal cells) Arrector pili muscle causes hair to raise, forming goose bumps Hair color is determined by relative amounts of eumelanin (black/brown) & pheomelanin (reddish color)

22. Hair (cont.) Shaft – portion of hair above the skin Root – portion of hair below the skin Follicle – sheath of epithelial and connective tissue that surrounds the hair Bulb – located at base of follicle Three phases in life cycle of each hair Anagen – the period of active growth (0.04 cm per day) Catagen – the period of involution (degeneration) when the lower part of the follicle below the arrector pili muscle atrophies Telogen – the resting period between the end of follicular atrophy and the shedding of the hair

23. Hair

24. Nails Comprised of hard keratin from stratum corneum Nail plate – hard portion of nail Nail bed Comprised of stratum basale and stratum spinosum Nail plate rests on the nail bed Nail root – proximal part of nail (covered by skin) Nail matrix – contains stem cells that cause nail to grow

25. Nails

26. Functions of Skin Protect against infection Protect against dehydration Membrane-coating granules (MCG’s) seal spaces between keratinocytes to prevent entry of pathogens and loss of water Regulate body temperature Vasoconstriction (blood vessels become narrower) – conserve heat Vasodilation (blood vessels open wider) – promotes radiation/dissipation of heat to surrounding air Sweat Sensory reception Pain Temperature changes Touch (and pressure)

27. Skin Discoloration Albinism – lack of melanin production due to genetic mutation Cyanosis – bluish skin color due to decreased O 2 in blood Jaundice – excessive bile pigments (bilirubin) in the blood causes skin to turn yellow in color

28. Cyanosis

29. Jaundice

30. (Colloidal Silver Staining)

31. Skin Disorders Dermatitis (aka, eczema) Inflammation of the skin Due to irritants such as oil of poison oak or poison ivy, detergents, acids, etc. Atopic Dermatitis Intense itching Skin inflammation Crusting of skin surface

32. Atopic Dermatitis

33. Skin Disorders (cont.) Psoriasis Faster than normal renewal of cells resulting in accumulation of cells in the stratum corneum Produces red (erythematous), flat areas (plaques) covered with silvery scales Unknown etiology (cause)

34. Psoriasis

35. Skin Disorders (cont.) Cancer Basal cell carcinoma – originates in stratum basale Caused by UV radiation Squamous cell carcinoma – originates in stratum spinosum Caused UV radiation or chemical agents Melanoma – malignant tumor of melanocytes Originates in a mole/birthmark (nevus) Irregular in shape Rapidly dividing cells

36. Basal cell carcinoma Squamous cell carcinoma Malignant melanoma Skin Cancer

37. Skin Disorders (cont.) Wart (aka, verruca) Small tumor Caused by viruses of the human papillomavirus (HPV) family