Patho Exam 2
Integumentary system
• SKIN- largest organ, 20% of body weight
• ACCESSORIES
1. hair 3. Gland
2. nails
• 1. PROTECTION
2. TEMPERATURE REGULATION
3. PROTECT AGAINST MICROOGRANISM
4. LOSS
...
Patho Exam 2
Integumentary system
• SKIN- largest organ, 20% of body weight
• ACCESSORIES
1. hair 3. Gland
2. nails
• 1. PROTECTION
2. TEMPERATURE REGULATION
3. PROTECT AGAINST MICROOGRANISM
4. LOSS OF BODY FLUIDS
5. STRESS OF MECHANICAL FORCES
6. PRODUCTION OF VITAMIN D
7. IMMUNE SURVEILLENCE
8. PLEASUREABLE SENSATION
• EPIDERMIS
Layers
1. superficial outer layer 4. stratum spinosum
2. stratum corneum 5. stratum germinativum
3. stratum lucidum 6. Stratum basale
• Keratinocytes- keratin
• Melanocytes- melanin
* Vitiligo- autoimmune related loss of melanocytes; depigmentation of patches of skin
• Langerhan cells- present processed antigen to T- cells
• Merkel cells- function as slowly adapting mechoreceptors
• DERMIS
1. deeper layer, true skin
2. collagen, elastin, reticulum, and a gel-like ground substance
3. hair follicles, sebaceous glands, sweat glands, blood vessels, lymphatic vessels, nerves
4. Fibroblast- secrete collagen
5. mast cells- release histamine
6. macrophages- phagocytic immune cells
* Histocytes- loose connective tissue; phagocytize pigments and debris of inflammation
• SUBCUTANEOUS LAYER
1. fat cell or adipocytes and connective tissue
2. dermal collagen is continuous w/ the subcutaneous collagen
3. macrophages, fibroblast, fat cells, nerves, fine muscles, blood vessels, lymphatics, and hair root follicles
• DERMAL APPENDAGES
1. hair, nails
2. Sebaceous glands- secrete sebum
3. Eccrine sweat glands- thermoregulate and cool the body through evaporation
4. Apocrine sweat glands – limited function
• Blood supply and innervation
1. papillary capillaries provide a rich supply of blood
2. sympathetic nervous system regulates vasoconstriction and vasodilation through a- adrenergic receptors
• PRIMARY LESIONS
1. Macule- flat, circumscribed area that a change in the color of skin (freckles, measles)
2. wheal- transient lesion w/ well defined and often changing borders caused by edema of the dermis ( insect bites, allergic reactions)
3. Papule- elevated, firm, and circumscribed area, measures less than 1 cm (warts)
4. Pustule- elevated, superficial lesion, filled with fluid ( acne, impetigo)
• SECONDARY LESIONS
1. Excoriation- loss of epidermis, linear, hollowed, crusted (scabies, scratches)
2. Fissure- linear crack or break from the epidermis to the dermis, maybe moist and dry (athlete’s foot)
3. Erosion- loss of a part of the epidermis, depressed area, moist, glisten, rupture of a vesicle or bulla (chicken pox, diaper dermatitis)
4. Ulcer- loss of epidermis and dermis, concave, varies in size (pressure sore)
5. pressure ulcer- result of an unrelieved pressure on skin, causing underlying tissue damage
* shearing forces, friction, moisture
* occlude capillary blood flow w/ resulting ischemia and necrosis
* STAGE 1 – nonblanchable erythema of intact skin
* STAGE 2- partial thickness, skin loss, involves epidermis or dermis
* STAGE 3- full thickness, skin loss, involving damage or subcutaneous tissue
* STAGE 4- Full thickness, skin loss w/ damage to muscle, bone, or supporting structures
• Decubitis ulcer- results when an individual lies or sits in one position for an extended period of time
• Dermatitis or Eczema
1. most common
2. characterized by pruritus, lesions w/ distinct borders, epidermal changes
3. Chronic eczema
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