The Skin in Health & Disease

1. The Skin in Health & Disease Chapter 6

2. outline • Observation of the skin • Color • pigment • discoloration • Lesions • surface • deeper • Burns • Tissue repair • Skin aging • Care of the skin • Skin disorders • Structure of the skin • Epidermis • Stratum basale • Stratum corneum • Dermis • Hypodermis • Accessory structure of the skin • Glands • Sebaceous (oil) glands • Sudoriferous (sweat) glands • Eccrine • apocrine • Hair • Nails • Functions of the skin

3. Integumentary System • Skin and associated structures form integumentary system • A membrane enveloping the body • Accessory structures aka appendages • Glands • Hair • nails

4. I. Structure of the Skin • Consists of two layers: • Epidermis – outer layer. Subdivided into thin layers called strata. Composed entirely of epithelial cells, no blood vesseles. • Dermis – “true skin”. Framework of connective tissues and contains: Blood vessels, nerve endings, and glands

6. a. Epidermis • Outermost surface of skin • Avascular – nourished by capillaries in underlying dermis • In the deepest layer, Stratum basale or stratum germinativum, new cells are produced and pushed upward • As the cells die, their cytoplasm is replaced by protein called keratin which tickens and protects the skin forming the upper layer of epidermis, stratum corneum • Exfoliation – the constant loss and replacement of cells

7. b. Dermis – “True Skin” • Framework of elastic connective tissue • Extensive blood & nerve supply • Most appendages in the dermis • Dermal papillae – extensions into the epidermis to allow for increased blood supply to the epidermis • Distinct ridge pattern which also help for grip • Basis of fingerprints & footprints

8. Dermal Papillae

9. Checkpoint 6-1:The skin and all its associated structures comprise a body system. What is the name of this system? Checkpoint 6-2:The skin itself is composed of two layers. Moving from the superficial to the deeper layer, what are the names of these two layers?

10. c. Subcutaneous Layer - Hypodermis • Connects skin to surface muscles • Composed of areolar & adipose tissue • Connected to dermis with continuous bundles of elastic fibers • Rich blood and nerve supply

11. II. Accessory Structures of Skin • Glands • Sebaceous (oil) glands • Sudoriferous (sweat) glands • Nails • Hairs

12. a. Sebaceous (Oil) Glands • Saclike exocrine glands with ducts that open into hair follicles • Secrete sebum • Lubricates skin • Prevents drying

13. b. Sudoriferous(sweat) Glands • Coiled exocrine glands in dermis & subcutaneous tissue • Eccrine – most numerous • Ducts release sweat directly onto surface of the skin as a pore • Cool the body • Apocrine – at armpits & groin • Activate at puberty • Secrete in response to emotional stress & sexual stimulation • Body odor results from bacteria breaking down substances secreted from these glands

14. Sweat Glands

15. Sudoriferous Glands • Ceruminous glands – secrete ear wax (cerumen) • Ciliary glands – at edges of eyelids • Mammary glands – in breast

16. c. Hair • Covers almost entire body • Except palms, soles, nipples, lips, some regions of external genitals • Nonliving – composed mainly of keratin • Developed from living cells in a bulb • Melanocytes give hair its color

17. Hair Continued • Hair follicle – sheath of connective & epithelial tissue that encloses hair • Shaft – part of hair above the skin • Arrectorpili – involuntary smooth muscle that forms goose bumps; causes release of sebum when contracts

18. d. Nails • Function • Protect fingers and toe • Help in grasping objects • Made of keratin • Changes in nails can be a result of disease processes

19. Nails • Structure • Nail root – under skin, where new cells grow • Nail plate – part of nail overlying skin • Nail bed – epithelial tissue under nail plate • Lanula – covers growing region of nail • Cuticle – extension of stratum corneum, seals space between nail plate and nail root

20. III. Skin Functions • Skin does NOT breathe • Protection against infection • Protection against dehydration • Regulation of body temperature • Collection of sensory information • Other minor skin functions • Limited absorption • Minimal excretion • Manufacture of Vitamin D

21. Skin Functions • Protection against infection • Stratum corneum is in a tight interlocking pattern & constantly being shed • Protection against dehydration • Keratin and sebum waterproof the skin and prevent water loss

22. Skin Functions • Regulation of body temperature • Excess heat dissipated • Large surface for heat to radiate into environment • Vessels dilate to allow heat loss • Sweat glands cause perspiration, which dissipates heat when it evaporates from surface of skin • Protection from cold • Vessels constrict to diminish heat loss • Most blood supply to skin is for temperature regulation

23. Skin Functions • Skin is one of chief sensory organs of body • Collection of sensory information • Free nerve endings • Pain • Temperature • Sensory receptors • Light touch – Meissner corpuscle • Deep pressure – Pacinian corpuscle

24. Minor Skin Functions • Limited absorption • Estrogens or steroids • Most skin medications are topical & local only • Minor excretion • Electrolytes (salts) • Some nitrogen-containing wastes • Vitamin D production • Needed for bone health • Manufactured in skin under UV radiation

25. IV. Observation of the skin a. Color • Dependant on many factors • Amount of pigmentation • Blood flow to surface blood vessels • Quality of blood flow to surface vessels • Quantity of oxygen • Concentration of hemoglobin • Presence of compounds such as bile

26. Skin Pigmentation • Melanin – main skin pigment • Also found in hair, iris of the eye, middle coat of the eyeball • Protects against UV radiation • Tanning – normal increase in melanin • Albinism – hereditary lack of pigment in skin, hair & eyes • Carotene – in orange & yellow vegetables and stored in fatty tissue & skin • Hemoglobin – seen in vessels near surface

27. Albinism

28. Discoloration of Skin • Pallor – is paleness of the skin. Paleness often due to loss of blood supply or loss of hemoglobin • Most easily noted in lips, nail beds, mucous membranes • Flushing – reddening of skin, often related to fever • Most noticeable in face and neck • Cyanosis – bluish tone as a result of loss of oxygen • Symptom of heart failure breathing problems • Jaundice – yellowish skin due to excessive bile pigments from liver, mainly bilirubin • Tumors, inflammation of liver (hepatitis), some blood diseases • Neonates with immature livers may not be able to process bilirubin • Carotenemia – excessive intake of carrots leading to jaundice

29. Pallor Cyanosis

30. Cyanosis Jaundice

31. Jaundice Carotenemia

32. b. Skin Lesions • Lesion – any wound or local damage to tissue • Surface lesions – • Rashes - flat • Eruptions – raised • Erythema – redness of skin due to inflammation • Deep lesions • Burns

33. Surface Skin Lesions • Macule – flat spot, neither raised or depressed • measles • freckles • Papule – firm raised bump • Pimple • Nodule – large papule • Vesicle – raised area filled with fluid • Aka bulla • Chickenpox • Pustule – raised area filled with pus • Infected vesicles

34. Stages of Chickenpox

35. Deep Skin Lesions • Excoriation – a scratch • Laceration – rough jagged wound due to skin tearing • Ulcer – due to disintegration death of tissue • Decubitis ulcer – bed sore • Fissure – crack in skin • Athlete’s foot

36. Burns to Skin • Caused by heat, electricity, chemicals, abrasions • Assessed in terms of depth and %age of body surface involved • Replaces 1st, 2nd & 3rd degree burn classification

37. Classifying Skin Burns - Depth Superficial partial-thickness – epidermal involvement, may or may not be dermis involvement, • Reddened, may blister • Like a sunburn

38. Classifying Skin Burns - Depth Deep partial-thickness – epidermal and some dermal involvement • Blistered, broken skin with weeping appearance • Scalded appearance

39. Classifying Skin Burns - Depth • Full-thickness – epidermis, entire dermis and possibly some hypodermis • Broken, dry, pale skin • Charring may be present • May require grafting or loss of tissue

40. Classifying Burns to Skin – Body Surface Area • Rule of nines • Body surface is assigned percentage in multiples of nine • Lund & Browder – more accurate, divides body into small areas

41. Burns

42. Complications of Burns • Infection • Respiratory complications • Circulatory problems • Psychological impact • http://www.metacafe.com/watch/888126/drunk_driving_jacqueline_saburido/

43. Sunburn • Excessive exposure to UV radiation • Acute - sunburn • Chronic • Skin cancer – basal cell & squamous cell carcinoma, malignant melanoma • Wrinkling, age spots and “leathering” • Tanning no safer than sunlight

44. SPF Sun Protection Factor • A measure of UVB protection • Ranges from 1 to 45 or above. • An SPF of 15 will delay sunburn in a person who would otherwise burn in 10 minutes to burn in 150 minutes. The SPF 15 sunscreen allows a person to stay out in the sun 15 times longer. • There is currently no uniform measure of UVA absorption so SPF does not predict UVA protection • The "protectiveness" of clothing can also be measured by SPF. The following are SPF's of various types of clothing: • Nylon Stockings - SPF 2 • Hats - SPF 3-6 • Summer-weight clothing - SPF 6.5 • Sun-protective clothing - up to SPF 30

46. v. Skin Tissue Repair • Begins after clotting & scabbing protects underlying tissue • Healing occurs from the inside out in wounds • Scar aka cicatrix – growth of connective tissue – strong but not flexible • Keloid – excessive scar tissue

48. Keloid

49. VI. Aging & Integumentary System • Loss of fat & collagen • Thinning of dermis – “parchment skin” • Circulation declines – decreased ability to tolerate cold • Decreased melanin production – grey hair • Decreased sebum secretion • Decreased eccrine & apocrine glands so decreased ability to tolerate heat

50. A. Young Skin B. Old Skin