Integument Lecture (1) PDF

Integument Lecture (1) Integument Composed of skin and skin appendages Protects deeper tissues from injury, drying and invasion by foreign organisms Play important roles in Thermoregulation Absorbs ultraviolet light Metabolizes vitamin D Q: Know the layers of epidermis Layers of Skin: Come Let’s Get...

Integument Lecture (1) Integument Composed of skin and skin appendages Protects deeper tissues from injury, drying and invasion by foreign organisms Play important roles in Thermoregulation Absorbs ultraviolet light Metabolizes vitamin D Q: Know the layers of epidermis Layers of Skin: Come Let’s Get Sun Burnt Epidermis o Stratum Corneum o Stratum Lucidum o Stratum Granulosum o Stratum Spinosum o Stratum Basale Dermis o Papillary dermis o Reticular dermis Biopsy: If possible, biopsy a primary lesion Biopsy characteristic areas in their diagnostic stage, NOT ruptured bullae, secondarily infected/scratched areas or involuting lesions Try to include a margin with both lesion and surrounding normal skin Captures histopathology only at one point in time in evolution of a lesion Shave Biopsy: Removal of a "shave" superficial lesion tissue and/or to establish a diagnosis Punch Biopsy: Removal of a "core" of tissue to establish a definitive diagnosis or to remove a small lesion Q: Which biopsy is used for a superficial lesion? - Shave Q: Which biopsy is used for a small lesions? - Punch Definitions: Macule o Circumscribed flat colored area 10mm) Papule o Elevated, solid area 10mm Nodule o Solid, palpable, >10mm Tumor o Solid, palpable >20mm Cyst o Encapsulated cavity or sac lined by true epithelium o Squamous lined o Filled w keratin Blister: Vesicle or bullae o Vesicle § Fluid filled area 10mm o Pustule § Intraepidermal/Subepidermal vesicle or bullae filled w pus Erosion o Discontinuity of skin causing partial loss of epidermis Ulceration o Discontinuity of skin causing complete loss of epidermis and possible loss of dermis Fissure o Canyon-like crack through the epidermis and into the dermis o NO tissue lost Excoriation o Deep, linear scratch o Often self induced Wheals o Itchy, transient, elevated area w variable blanching and erythema due to dermal edema (erythema of the skin is due to dermal edema) Scale o Dry, plate like excrescence usually due to excess stratum corneum Crust o Hardened layer resulting from serum, blood, purulent exudate drying on skin surface Purpura o Extravasation of RBCs into the skin or mucous membranes o Extraversion means RBC “float out” Erythema o Redness of skin due to increased blood flow o NOT leakage of blood into the skin, may blanch Telangiectasia o Visible persistent dilation of small, superficial cutaneous blood vessels o May blanch Histological Changes: Hyperkeratosis o Thickened cornified layer o Prominent granular layer Parakeratosis o Cells of cornified layer retain nuclei o Less prominent or absent granular layer (normal for mucous membranes) Acanthosis o Thickened squamous epidermis o Rete ridges extend deep into dermis Hypergranulosis o Hyperplasia of Stratum Granulosum o From intense rubbing Spongiosis and Vesicles o In Stratum Spinosum, Intraepidermal edema causes keratinocytes to splay apart o Vesicle formation due to sheared desmosomes Acantholysis o Loss of desmosomes btwn keratinocytes o Cell shape changes from polygonal to round Dyskeratosis o Premature keratinization of keratinocytes below granular layer o Bright eosinophilic cytoplasm