Untitled Flashcard Set

Intro & Overview

Term: Integumentary System
Definition: Protective covering and first line of defense.

Term: Skin Trivia
Definition: 21 sq ft, 4 kg/9 lbs, 7–15% of body weight; continuous layer; complex tissues.

Term: One Square Inch of Skin Contains
Definition: 20 blood vessels, 65 hairs & muscles, 78 nerves, 78 heat sensors, 13 cold sensors, 160 pressure sensors, 100 oil glands, 19,500,000 cells, 0.5 million cells dying/being replaced.

Term: Layers/Regions of the Skin
Definition: Epidermis (superficial), Dermis (fibrous connective tissue, vascularized), Hypodermis (fat, anchors skin, absorbs shock).

Term: Functions of Skin
Definition: Protection, water balance, temperature regulation, waste disposal, receptor organs, blood reservoir, vitamin D production.

Epidermis & Layers

Term: Epidermis
Definition: Outer layer of stratified squamous epithelial tissue; avascular; regenerates every 35–45 days; thinner on scalp/armpit than sole.

Term: Layers of Epidermis
Definition: Stratum basale, spinosum, granulosum, lucidum, corneum.

Term: Stratum Basale (Germinativum)
Definition: Deepest layer; stem cells; melanocytes (10–25%); makes melanin; genetic absence of tyrosinase = albinism.

Term: Stratum Spinosum
Definition: Spiny layer; several layers thick; Langerhans cells; tonofilaments resist tension.

Term: Stratum Granulosum
Definition: 3–5 layers of flattened keratinocytes; keratohyaline granules form keratin; lamellated granules waterproof; slows water loss.

Term: Stratum Lucidum
Definition: Clear layer in thick skin (palms, soles); absent in thin skin; 2–3 rows of dead keratinocytes.

Term: Stratum Corneum
Definition: Outermost horny layer; 20–30 cell layers; protects deeper cells; dandruff = shedding; hyperkeratosis = thick, dry, scaly skin.

Dermis

Term: Dermis
Definition: Two layers (papillary & reticular); strong, flexible connective tissue.

Term: Characteristics of Dermis
Definition: Fibroblasts, macrophages, mast cells, collagen, elastin; wrinkles from loss of elastin/fat.

Term: Papillary Layer of Dermis
Definition: Areolar connective tissue; dermal papillae with capillary loops, Meissner’s corpuscles (touch), free nerve endings.

Term: Reticular Layer of Dermis
Definition: Dense irregular CT; 80% dermis; collagen & elastin provide stretch/strength.

Term: Contents of Dermis
Definition: Blood vessels, capillaries, lymphatics, nerves, hair follicles, sweat glands (eccrine/apocrine), sebaceous glands, ceruminous glands, arrector pili, sensory receptors.

Accessory Organs

Term: Hair
Definition: Pili made of keratin; shaft projects from skin; root embedded; shape = straight/curly; pigment from melanocytes.

Term: Hair Follicle
Definition: Root + papilla supplies nutrients; arrector pili raises hair.

Term: Sudoriferous (Sweat) Glands
Definition: 2.5 million per person; cover most of skin except nipples/genitals.

Term: Eccrine Sweat Glands
Definition: Most numerous; palms, soles, forehead; secrete watery sweat (99% water, salts, waste); acidic pH 4–6; temp regulation; no control over emotional sweating.

Term: Apocrine Sweat Glands
Definition: Axillary/anogenital; ducts empty into hair follicles; viscous secretion; begins at puberty; sexual scent/stress response.

Term: Ceruminous Glands
Definition: Modified apocrine in ear; secrete cerumen (earwax).

Term: Sebaceous (Oil) Glands
Definition: All over except palms/soles; secrete oily sebum; lubricates skin/hair; slows water loss; blocked duct = acne.

Nails

Term: Nail Structure
Definition: Free edge, body, root, lunula, nail folds, nail bed, hyponychium.

Term: Nail Anatomy
Definition: Grows under nail matrix; made of keratin; cells replaced if matrix is intact.

Skin Cancer

Term: Skin Cancer Causes
Definition: Benign tumors = warts/moles; malignant = spread; risk: UV, radiation, genetics.

Term: Basal Cell Carcinoma
Definition: Most common, least malignant; stratum basale; slow-growing; cured by removal.

Term: Squamous Cell Carcinoma
Definition: From keratinocytes in stratum spinosum; scaly red; grows fast, may metastasize; good prognosis if removed early.

Term: Melanoma
Definition: Cancer of melanocytes; most dangerous; highly metastatic, resistant to chemo; ABCD rule (Asymmetry, Border, Color, Diameter >6mm).

Burns

Term: First-Degree Burns
Definition: Only epidermis; redness, pain, swelling; heals in 2–3 days (e.g., sunburn).

Term: Second-Degree Burns
Definition: Epidermis + upper dermis; blisters, pain, swelling; heals with some scarring.

Term: Third-Degree Burns
Definition: Entire skin destroyed; gray/white/red/black; no pain (nerves destroyed); requires grafts.

Miscellaneous

Term: Fingerprints
Definition: Dermal papillae form ridges; unique to each individual.