Download Introduction to Dermatology: Skin Anatomy, Layers, Cell Types, and Lesions and more Study notes Dermatology in PDF only on Docsity!
Clinical Medicine Intro to Derm
Objectives
Review the basic anatomy of the skin and its layers Skin Layer Function/characteristics Epidermis Topmost layer, primarily keratinocytes Dermis Fibroblasts, collagen, elastic fivers Hypodermis Adipose, sweat glands, blood vessels, lymphatics, adnexal structures (hair follicles, sebaceous glands, apocrine and eccrine glands) Epidermal Layer Characteristics Function Stratum Corneum Most superficial layer; 15- layers of dead flattened, anucleate, keratin-filled keratinocytes; fully keratinzed squames Protects against friction and water loss Stratum Lucidum 2-3 layers of anucleate, dead cells; thin, translucent flattened cells, seen only in thick skin Protect against friction water loss; reinforce skin strength; reduce friction between stratum corneum and stratum granulosum Stratum granulosum 3-5 layers, flattened cells going through keratinization. with distinct kerato-hyaline granules Barrier against water loss in skin Stratum Spinosum Thickest layer; keratin filaments assemble into tonofibrils—create spines at cell surface; thick skin has thicker stratum spinosum provide strength and flexibility by tightly connecting keratinocytes together with desmosomes
Stratum Basale Deepest, single layer of cuboidal to low columnar cells; in contact in basement membrane; intense mitosis occurs here via stem cells; melanocytes and merkel cells here; hemidesmosomes in basal cell membranes join these cells to basal lamina; desmosomes bind cells in this layer together Continuously produce new cells; attach epidermis to underlying dermis through basement membrane Know the cell types of the epidermis and dermis Layer Cell Types Epidermis Keratinocytes, melanocytes, Langerhans cells Dermis Fibroblasts, mast cells, Be able to describe the various roles that the skin has
- Mechanical barrier a. Desiccation, infection, heat loss, UV damage, water loss
- Immunologic barrier a. Senses and responds to pathogens
- Fluid balance
- Temperature regulation a. Maintain core temp;sweat evaporation;regulation of blood flow; hair and fat insulate
- Nerve sensation a. 3 major nerve fiber types: i. A fibers-large, heavily myelinated, transmit tactile sensation ii. A fibers- thinly myelinated, transmission of short and fast painful stimuli iii. C-fibers: unmyelinated; transport pain and itch sensations
Plaque Plateau-like lesion >10 mm in diameter. Pustule Vesicle or bullae containing purulent material (pus) Vesicle Circumscribed, elevated skin lesion containing serous or bloody fluid <10 mm in diameter Bullae Circumscribed, elevated skin lesion containing serous fluid > mm in diameter.
Wheal Transient, elevated lesion caused by local edema Secondary Morphology/Secondary Lesions Lesion type Description Scale Loose or adherent flakes of stratum corneum Crust Hard, rough surface formed by dry serum, pus and/or blood; may be black, brown, yellow or green
Ulcer Loss of entire epidermis and part of dermis; Stages 1- Eschar Black, hard crust from tissue necrosis atrophy Depression or surface change as result of loss of compartments of epidermis, dermis, or fat
Scar Depressed or elevated proliferation of tissue Petechiae Pinpoint purple/red/brown spots, bleeding under the skin, don’t blanche Purpura Purple colored spots and patches; 4-10 mm; small blood vessels leak blood under the skin Ecchymosis (bruises) purpuric flat patches on skin > 1 cm, greater volume of extravasated blood
Burrow Wavy, threadlike tunnel through outer portion of epidermis; excavated by parasite; open end of tunnel has papule Sinus Tract connecting deep cavities to each other or to surface of skin Color and Color Change Color Example Pale pink Edema or dilated blood vessels Pink Dilated blood vessels Red Dilated blood vessels or extravasated blood Purple Dilated blood vessels or extravasated blood
Yellow Carotenemia, bilirubinemia Brown Increased melanin or dermal hemosiderin Black Increased melanin, necrotic skin White Decreased or absent melanin, vasoconstriction Patterns and Shapes Annular Ring-shaped; edge differs from center (raised/scaly) Round/nummular/ discoid Coin shaped lesion; uniform throughout Arcuate Arc-shaped
Linear/ streak Arranged in linear formations Dermatom al Starts at spinal area, distributed along a dermatome Serpiginous Serpentine, wavelike in shape
Reticular Lace or net like Symmetrica l Uniform distribution on axis of body Generalized Spread over wide areas of the body
Usually alcohol based, sting compromised skin Foam/mousse Pressurized gas in liquid; melts at body temp; quick drying, little reside;scalp/hair bearing areas Powders Absorb moisture, reduce friction, cover large areas; best applied to intact skin Practice quiz links University of Wisconsin-Madison Department of Pediatrics Dermatology Quiz https://elentra.healthsci.queensu.ca/assets/quizzes/derm-morph-quiz/
