Pathophysiology - Integumentary System & Skin Disorders Questions and Answers Already Passed

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 Carotene additional pigment that gives a yellow color to the skin Dermis thick layer of connective tissue that includes elastic and collagen fibers and varies in thickness over body; contains nerves and blood vessels; contains sensory receptors for pressure or texture, pain, heat or cold Embedded in the skin are the appendages, or accessory structures, which are hair follicles, sweat and sebaceous glands, and nails Hair Follicles lined by epidermis, the stratum basale produces the hair; smooth muscle is attatched to it (arrector pili which is controlled by sympathetic nerves) which create goose bumps Sebaceous Glands produce an oily secretion, sebum, which keeps hair/skin soft Sweat glands (two types) Eccrine (merocrine) glands located all over body and secrete sweat through pores in response to increased heat or emotional stress (SNS control) Apocrine glands located in the axillae, scalp, face, and external genitalia, & the ducts of glands open into hair follicles 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 2. prevents excessive fluid loss 3. controlling body temperature using 2 mechanisms: cutaneous vasodilation (increases peripheral blood flow), and increased secretion and evaporation of sweat 4. sensory perception which is a defense against environmental hazards, as a learning tool, and as a means of communicating emotions 5. 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 Erosion shallow, moist cavity in epidermis Comedone mass of sebum, keratin, and debris blocking the opening of a hair follicle Pruritus release of histamine in hypersensitivity response; associated with allergic responses, chemical irritation due to insect bites, or infestations by parasites; common manifestations include redness and itchiness Contact Dermatitis caused by exposure to an allergen, direct chemical, or mechanical irritation Allergic Dermatitis manifestations such as a prutitic rash develop at the site a few hours after exposure to that allergen; indicated by pruritic, erythematous, and edematous area, covered with vesicles Urticaria results from type I hypersensitivity, commonly caused by ingested substances; release of histamine causes eruption of hard, raised erythematous lesions (hives) 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 Impetigo Staphylococcus aureus is highly contagious in neonates, older children infection results from S. aureus but can be caused by group A beta-hemolytic streptococci; spread by direct contact; topical antibiotics can be used in early stages, but systemic administration of these drugs is necessary if the lesions are extensive Acute Necrotizing Fasciitis flesh eating disease; rapid tissue invasion resulting from reduced blood supply to tissue and secretion of protease enzymes that destroy tissue; results from virulent strain of gram-positive, group A, beta-hemolytic Streptococcus; symptoms similar to cellulitis; can treat with aggressive antimicrobial therapy, fluid replacement, excision of all infected tissue, high oxygen flow in hyperbaric chambers, possibly amputation Leprosy (Hansen's disease) caused by bacterium Mycobacterium leprae; problem in Africa, Asia, South Pacific, and South America; not highly contagious, extended contact with source is required for infection; affect skin, mucous membranes, and peripheral nerves; can treat with antibiotics Herpes Simplex cold sores; can be asymptomatic; reinfection can be caused by common cold, sun exposure, or stress; acute stage can by reduced by topical application of antiviral drugs (acyclovir, Zovirax); contagious through direct contact with fluid from lesion 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 2. cover up with clothing, remain in shade, wear broad-brimmed hats to protect face and neck 3. apply sunscreen to protect from UVA and UVB rays 4. protect infants and children from exposure and sun damage Squamous Cell Carcinoma similar to common basal cell carcinoma; excellent prognosis when lesion is removed in a reasonable time; sun exposure is contributing factor; smokers have higher incidence of this tumor in the lower lip; invasisve type of this cancer arises from premalignant conditions such as leukoplakia; develops as scaly, slightly elevated, reddish lesion with irregular border and central ulceration Malignant Melanoma develops from melanocytes in basal layer and is increasing in incidence; development depends on genetic factors, exposure to UV radiation, and hormonal influences; arise from melanocytes in the basal layer of the epidermis or from a nevus (mole); often appears as multicolored lesion with irregular border, grow quickly extending into tissues and metastasize into regional lymph nodes; after surgical removal of lesion, additional radiation and chemotherapy can provide a 5-year survival rate Kaposi's Sarcoma rare type of skin cancer; association with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS); occurred in older men originating from Eastern Europe or Mediterranean area before HIV pandemic; can affect the viscera and skin; Herpesvirus #8 forms part of the etiology; arise from endothelium in small blood vessels, form large, irregularly shaped plaques or nodules; combination of radiation, chemotherapy, surgery, and biologic therapy are common treatments