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Chapter Objectives

Chapter Objectives

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Chapter Objectives

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  1. Chapter Objectives • Epidermis, dermis and subcutaneous tissues. • Roles of keratin and melanin in the skin. • The glands in the skin. • The structure of hair and of nails. • Roots pertaining to the skin. Chapter 21: The Skin

  2. Key TermsNormal Structure and Function

  3. Key TermsNormal Structure and Function (cont’d)

  4. Key TermsDisorders

  5. Key TermsDisorders (cont’d)

  6. Key TermsDisorders (cont’d)

  7. Key TermsDisorders (cont’d)

  8. Supplementary TermsSymptoms and Conditions

  9. Supplementary TermsSymptoms and Conditions (cont’d)

  10. Supplementary TermsSymptoms and Conditions (cont’d)

  11. Supplementary TermsSymptoms and Conditions (cont’d)

  12. Supplementary TermsSymptoms and Conditions (cont’d)

  13. Supplementary TermsSymptoms and Conditions (cont’d)

  14. Supplementary TermsSymptoms and Conditions (cont’d)

  15. Abbreviations

  16. Abbreviations (cont’d)

  17. Roots Pertaining to the Skin

  18. Anatomy of the Skin • Skin is part of integumentary system • Epidermis = outermost layer • 4-5 layers of epithelial cells • Stratum basale • Deepest layer of epidermis • Produces new skin cells • New skin cells gradually rise to surface • As skin cells rise: • Cells die • Cells fill with keratin

  19. Anatomy of the Skin (cont’d) • Stratum corneum = outermost layer of epidermis • Flat, dead, protective cells • Constantly shed and replaced • Some cells produce melanin • Gives color to skin • Protects against sunlight

  20. Dermis & Subcutaneous Tissue • Dermis = layer beneath epidermis • Connective tissue • Nerves • Blood vessels • Lymphatics • Supports and nourishes skin • Subcutaneous tissue = layer beneath dermis • Connective tissue • Fat

  21. Cross Section of the Skin

  22. Associated Skin Structures • Sudoriferous glands (sweat glands) • Regulate temperature • Release watery fluid (sweat) • Sweat evaporates cooling the body • Sebaceous glands • Release sebum (oily fluid) • Lubricates hair and skin to prevent drying

  23. Associated Skin Structures (cont’d) • Hair • Nonliving material, mainly keratin • Develops within follicle • Grows from base within deep layers of skin • Functions as protection • Nails • Nonliving material, mainly keratin • Develops from growing region at proximal end • Functions as protection

  24. Clinical Aspects of the Skin • Dermatology = study of skin and skin diseases • Observation of skin, hair, nails part of every physical examination • Skin observed for color, unusual pigmentation, lesions • Palpated to evaluate texture, temperature, moisture, firmness, tenderness

  25. Wounds • Caused by: • Trauma • Surgery • Complicated by: • Infection • Hemorrhage • Dehiscence = disruption of wound layers • Evisceration = protrusion of internal organs through lesion

  26. Wound Healing • As wound heals: • Fluid and cells drain from damaged tissue • Exudate may be: • Clear • Bloody • Pus-containing

  27. Wound Healing (cont’d) • Proper wound healing: • Cleanliness and care of lesion • Proper circulation • Good general health and nutrition • Accompanied by cicatrization (scar formation)

  28. Promotion of Healing • Vacuum-assisted closure = negative pressure to close tissues • Debridement = removal of dead or damaged tissue • Cutting or scrubbing • Enzymes • Escharotomy (removal of scar)

  29. Promotion of Healing (cont’d) • Skin graft • For deep wounds • Full thickness skin graft (FTSG) • Epidermis and dermis • Split-thickness skin graft (STSG) • Epidermis • Done with dermatome

  30. Burns • Caused by: • Hot objects • Explosions • Scalding • Electrical malfunctions • Contact with harmful chemicals • Abrasion • Assessed by: • Depth of damage • Percentage of body surface area affected

  31. Burn Categorization • Superficial partial thickness • Involves epidermis, possibly dermis • Tissue reddens, may blister • Deep partial-thickness • Involves epidermis and portions of dermis • Tissue blisters, has weeping surface

  32. Burn Categorization (cont’d) • Full-thickness • Involves full skin, possibly subcutaneous tissue • Broken, dry and pale or charred tissue • May result in loss of digits or limbs • May require skin grafting

  33. Burn Categorization (cont’d) • Percentage of body surface area • Rule of nines • Areas of body surface assigned percentages in multiples of nine • Lund and Browder • More accurate • Divides body into small areas • Estimates proportion each area contributes

  34. Burn Treatment • Includes: • Respiratory care • Administration of fluids • Wound care • Pain control • Monitoring for complications • Infections • Cardiovascular • Respiratory • Posttraumatic stress

  35. Pressure Ulcers • Necrotic skin lesions • Body resting on skin covering bony projections • Sacrum • Heel • Elbow • Ischial bone of pelvis • Greater trochanter of femur

  36. Pressure Ulcers (cont’d) • Interrupts circulation • Thrombosis • Ulceration • Death of tissue • Contributing factors: • Malnutrition • Age • Obesity • Infection

  37. Pressure Ulcers (cont’d) • Progression • First appear as redness of skin • If ignored may penetrate: • Skin • Underlying muscle • Bone • May require months to heal

  38. Pressure Ulcers (cont’d) • Prevention • Pads or mattresses to relieve pressure • Regular cleansing and drying of skin • Frequent change in position • Good nutrition

  39. Dermatitis • Inflammation of skin • Example: Eczema (atopic dermatitis) • Chronic allergic form • Exact cause unknown, but made worse by: • Allergies • Infection • Temperature extremes • Skin irritants

  40. Dermatitis (cont’d) • Other forms: • Contact dermatitis • Seborrheic dermatitis • Stasis dermatitis

  41. Psoriasis • Chronic overgrowth of epidermis • Large erythematous plaques with silvery scales • Cause unknown, but may be linked with: • Hereditary pattern • Autoimmunity • Treatment • Topical corticosteroids • Exposure to UV light • Systemic suppression of immune system

  42. Autoimmune Disorders • Pemphigus • Characterized by formation of blisters • Occurs in skin and mucous membranes • Caused by separation of epidermal cells from underlying layers • Deep skin unprotected from infection and fluid loss • Caused by autoimmune reaction • Fatal unless immune system is suppressed

  43. Autoimmune Disorders (cont’d) • Lupus Erythematosus • Chronic inflammatory autoimmune disease of connective tissue • Discoid • Involves only the skin • Systemic lupus erythematosus • Involves skin and other organs • Symptoms • Rough, raised, violet-tinted papules • Worsened by exposure to UV rays

  44. Scleroderma • Thickening and tightening of skin • Unknown cause • Overproduction of collagen • Involves hair follicles and sweat glands • Early signs: • Raynaud disease • Skin symptoms first appear on forehead, around mouth

  45. Skin Cancer • Most common type of human cancer • Increasing rate due UV rays • Common types • Squamous cell carcinoma • Basal cell carcinoma • Malignant melanoma • Kaposi sarcoma

  46. Skin Cancer (cont’d) • Squamous cell carcinoma • Cancer of epithelial cell • Occurs in areas exposed to sunlight • Painless, firm red nodule • May invade underlying tissue • Tends not to metastasize • Treatment • Surgical removal • X-irradiation • Chemotherapy

  47. Skin Cancer (cont’d) • Basal cell carcinoma • 75% of all skin cancers • Cancer of epithelial cell • Occurs in areas exposed to sunlight • Smooth, pearly papule • After excision, cure rate 95% • Easily seen • Tends not to metastasize

  48. Skin Cancer (cont’d) • Malignant melanoma • Overgrowth of melanocytes • Metastasizing tendency • First appears as lesion • May spread superficially before invading deeper tissues • Prognosis good if lesion removed before reaching deeper tissues

  49. Skin Cancer (cont’d) • Kaposi Sarcoma • Frequently associated with AIDS • Distinct brownish area on legs • As tumor progresses: • Plaques become raised and firm • Cancer can metastasize

  50. Pretest The uppermost portion of the skin is called the: (a) fossa (b) cuticle (c) epidermis (d) epiphysis