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Pathophysiology - Integumentary
System & Skin Disorders Questions and
Answers Already Passed
Skin is the _________ organ of body in surface area and weight. ✔✔largest
Dermatology ✔✔is the medical specialty concerning the diagnosing and treatment of skin disorders
What are the two layers of skin called? ✔✔epidermis and dermis
Epidermis ✔✔consists of 5 layers varying in thickness; does not contain blood vessels or nerves; contains melanocytes
What are the 5 layers of the epidermis in order from the innermost layer to the outermost layer? ✔✔stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
Stratum Basale ✔✔innermost layer of epidermis; new squamous epithelial cells form through mitosis in this layer; only layer where mitosis occurs; from this layer, the epithelial cells are then moved upward forming each layer of the epidermis
Stratum Corneum ✔✔outermost layer of the epidermis that consists of many layers of dead, flat, keratinized cells that are sloughed from the surface after being formed in the basal layer
Keratin ✔✔a protein found in skin, hair, and nails which is deposited into the epithelial cells; prevents loss of body fluid through the skin and entry of excessive water into the body
Melanin ✔✔specialized pigment-producing cells, dark pigment; this cell production depends on genes and environmental factors (sun exposure or ultraviolet light)
Albinism ✔✔recessive trait leading to a lack of melanin production; person has white skin and hair and lacks pigment in the iris of the eye; must avoid sun exposure
Vitiligo ✔✔small areas of hypopigmentation
Melasma or Chloasma ✔✔patches of darker skin
Beneath the dermis is the _____________ or _____________, which consists of connective tissue, fat cells, macrophages, fibroblasts, blood vessels, nerves, and base of many appendages ✔✔subcutaneous tissue, hypodermis
5 functions of the skin ✔✔1. first line of defense against invasion by microorganisms and other foreign material
- prevents excessive fluid loss
- controlling body temperature using 2 mechanisms: cutaneous vasodilation (increases peripheral blood flow), and increased secretion and evaporation of sweat
- sensory perception which is a defense against environmental hazards, as a learning tool, and as a means of communicating emotions
- synthesis and activation of vitamin D on exposure to small amounts of ultraviolet light
Macule ✔✔freckle; small, flat, circumscribed lesion of a different color than the normal skin
Papule ✔✔insect bite; small, firm, elevated lesion; epidermal and papillary
Nodule ✔✔cyst; palpable elevated lesion; varies in size; extends into the subcutaneous layer
Pustule ✔✔acne; elevated, erythematous lesion, usually containing purulent exudate (pus)
Vesicle ✔✔elevated, thin-walled lesion containing clear fluid (blister)
Plaque ✔✔large, slightly elevated lesion with flat surface, often topped by scale
Crust ✔✔dry, rough surface or dried exudate or blood
Lichenification ✔✔thick, dry, rough surface (leather-like)
Keloid ✔✔raised, irregular, and increasing mass of collagen resulting from excessive scar tissue formation
Fissure ✔✔small, deep, linear crack or tear in skin
Ulcer ✔✔cavity with loss of tissue from the epidermis and dermis, often weeping or bleeding
Atopic Dermatitis ✔✔inherited tendency toward allergic conditions; chronic inflammation; eosinophilia and increased serum IgE levels indicate allergenic basis for this; infants = moist, red, vesicular, and covered with crusts; adults = dry and scaling with lichenification; topical glucocorticoids are helpful
Psoriasis ✔✔chronic inflammatory skin disorder; results from abnormal activation of T cells and increase in cytokines which then lead to excessive proliferation of keratinocytes and symptoms of disease; rate of cellular proliferation is greatly increased which leads to thickening of dermis and epidermis; treatments reducing cell proliferation include glucocorticoids, tar preparations, antimetabolite methotrexate
Pemphigus ✔✔autoimmune disorder; autoantibodies disrupt cohesion between epidermal cells causing blisters to form; systemic glucocorticoids such as prednisone and immunosuppressants are used; 3 forms (pemphigus vulgaris, pemphigus foliaceus, and pemphigus erythematosus
Scleroderma ✔✔skin disorder that can be systemic and affect viscera; cause is not known but increase collagen deposition is observed in all cases, which reduces blood flow to skin or internal organs; inflammation and fibrosis can occur; cutaneous form can decrease microcirculation resulting in renal failure, intestinal obstruction, or respiratory failure
Bacterial Infections ✔✔often caused by resident flora, or secondary infections
Staphylococcal infection ✔✔acne
Cellulitis (erysipelas) ✔✔infection of dermis and subcutaneous tissue, can be secondary to injury, furuncle, or ulcer; causative organism is Staphylococcus auereus or Streptococcus; frequently occurs in lower trunks in individuals with restricted circulation, or those immunocompromised; systemic antibiotics usually necessary along with analgesics for pain
Furuncles ✔✔infection by S. aureus which begins in hair follicle; squeezing boils can spread infection by autoinoculation, cause cellulitis; compression of these in nasal area may lead to thrombi or infection spreading to the brain
Carbuncles ✔✔collection of furuncles that form a large infected mass
Pus ✔✔composed of leukocytes (WBC), cellular debris from dead blood cells and bacteria and a thin protein rich fluid component
Verrucae ✔✔warts; caused by human papillomavirus (HPV); infection spreads by viral shedding of the surface skin; tend to persist even with treatment; local treatments including laser, freezing with liquid nitrogen, and topical medications with ASA compounds
Fungal Infections (mycoses) ✔✔diagnosed from scrapings of skin processed with potassium hydroxide, microscopic examination, culturing of samples; fungi live off the dead, keratinized cells of the epidermis (dermatophytes)
Tinea capitis ✔✔infection of scalp common in school-aged kids; can result from Microsporum canis transmitted from dogs or cats, or by Trichophyton tonsurans by humans; oral antifungals such as griseofulvin
Tinea corporis ✔✔infection of the body (ringworm); topical antifungals such as tolnaftate or ketoconazole
Tinea pedis ✔✔athlete's foot; Trichophyton mentagrophytes or Trichophyton rubrum; organisms may be normal flora; spreads easily from lesions under conditions of excessive warmth and moisture; topical tolnaftate is effective
Tinea unguium ✔✔onychomycosis; infection of the nails, particularly toenails; nail thickens and cracks
Scabies ✔✔invasion by a mite, Sarcoptes scabiei; topical treatment with lindane is effective
Pediculosis ✔✔pediculus humanus corporis is the body louse, pediculus pubis is the pubic louse, and pediculus humanus capitis is the head louse (cooties); topical permethrin, malathion, or pyrethrin is used to treat lice
Keratoses ✔✔benign lesions that are usually associated with aging or skin damage; Seborrheic keratoses result from proliferation of basal cells leading to oval elevation; Actinic keratoses occur on skin exposed to UV radiation and commonly arise in fair skins, can develop into squamous cell carcinoma
Reducing the risk of skin cancers ✔✔1. reducing sun exposure at midday and early afternoon
- cover up with clothing, remain in shade, wear broad-brimmed hats to protect face and neck
- apply sunscreen to protect from UVA and UVB rays
- protect infants and children from exposure and sun damage
