Medical Language: Chapter 3 - Dermatology and the Integumentary System

Comprehensive practice flashcards covering anatomical terms, skin layers, lesion classifications, dermatological diseases, diagnostic assessments, and surgical procedures from Chapter 3 Dermatology.

What is dermatology, and what are the primary responsibilities of a dermatologist?

Dermatology is the medical specialty that studies the anatomy and physiology of the integumentary system. Dermatologists use laboratory and diagnostic tests, medical and surgical procedures, and drugs to treat integumentary diseases.

What structures make up the integumentary system, and what is notable about the skin?

The integumentary system consists of the skin, nails, and subcutaneous tissue. The skin is the largest organ in the body.

What are the word parts and meanings in the terms 'integumentary' and 'cutaneous'?

Integumentary contains integument/o- (skin) and -ary (pertaining to). Cutaneous contains cutane/o- (skin) and -ous (pertaining to).

What are the two layers of the skin and what tissue types compose them?

The epidermis is the thin, outermost layer made up of epithelial tissues, and the dermis is the thick layer below the epidermis made up of connective tissue.

What are the characteristics of the squamous layer of the epidermis?

It is the upper part of the epidermis composed of living and dead cells. Surface cells are dead, filled with keratin, continually undergo exfoliation, and are slightly acidic to discourage microorganism growth.

What are the characteristics of the basal layer of the epidermis regarding cell division and blood supply?

The basal layer consists of living cells that constantly divide and are forced upward. The epidermis contains no blood vessels and relies on dermal vessels for nutrients.

What is the function of melanocytes, and what word parts compose this term?

Melanocytes produce the pigment melanin to absorb the sun's UV light. The word parts are melan/o- (black) and -cyte (cell).

What structural proteins, vessels, and structures are found within the dermis?

The dermis contains firm, white collagen proteins, elastic yellow elastin proteins, arteries, veins, nerves, hair follicles, sebaceous glands, and sweat glands.

What is a dermatome?

A specific area of skin that sends sensory information to a spinal nerve in the spinal cord (which returns a motor command to a muscle). The term also refers to a surgical medical instrument.

What do sebaceous glands produce and what is its function?

Sebaceous glands are exocrine oil glands that secrete sebum through a duct into a hair follicle to coat the hair shaft and moisturize the skin's surface.

What do sudoriferous glands secrete, and what causes the characteristic odor of sweat?

Sudoriferous glands are exocrine sweat glands that secrete sweat (water, sodium, and small amounts of waste) through a duct opening onto a skin pore. Sweat is odorless until it contacts bacteria on the skin surface.

What is piloerection, what word parts compose it, and why does it occur?

Piloerection occurs when cold temperatures cause tiny muscles at the base of hair follicles to contract, creating 'goosebumps'. Its word parts are pil/o- (hair), erect/o- (stand up), and -ion (action or condition).

What are the five parts of the nail?

The nail plate (hard flat part), nail root (under the skin on the upper surface of the finger), lunula (white half-moon at the base), cuticle (edge around the base), and nail bed (pink tissue under the plate).

What is subcutaneous tissue and what are its main functions?

Loose connective tissue beneath the dermis (abbreviated sub Q or subcu) composed of adipose tissue containing lipocytes. It cushions, insulates the body, and protects internal organs.

How much weekly sunlight exposure is recommended for light-skinned individuals to synthesize adequate vitamin D?

$20\text{--}45\text{ minutes}$ per week.

What mechanisms does the skin use for thermoregulation?

Subcutaneous adipose stores heat, piloerector muscles contract to create surface heat, sudoriferous glands produce cooling sweat, and dermal blood vessels dilate to release heat.

What clinical phenomenon is demonstrated when fingertip pressure creates a deep, lingering indentation in swollen skin?

Pitting edema.

How are a macule and a papule differentiated in dermatology?

A macule is a flat circle with brown or black pigment containing no fluid or solid core (e.g., freckle, age spot), whereas a papule is an elevated, solid, skin-colored or erythematous lesion (e.g., acne pimple).

How are pustules and vesicles differentiated based on their contents and appearance?

A pustule is elevated with a white top and filled with pus (e.g., acne whitehead), whereas a vesicle is elevated with a pointed, transparent top filled with clear fluid (e.g., herpes, shingles).

What is xeroderma, and what word parts form the term?

Excessive dryness of the skin, derived from xer/o- (dry) and -derma (skin).

What is cyanosis, and what is its medical significance at birth?

A bluish-purple discoloration of the skin and nails (cyan/o- = blue, -osis = condition/process). It is a normal temporary finding of the face and arms at birth that resolves as the infant cries and inhales oxygen.

What causes the skin changes seen in vitiligo?

Vitiligo is an autoimmune disorder in which melanocytes are slowly destroyed, causing progressive, irregular white patches of depigmentation interspersed with normally pigmented skin.

How are superficial burns and full-thickness burns differentiated by anatomical depth and symptoms?

A superficial (first-degree) burn involves only the epidermis, presenting with erythema, pain, and swelling without blisters. A full-thickness (third-degree) burn involves the epidermis, dermis, and sometimes sub Q/muscle; destroyed dermal nerves cause local anesthesia and loss of pain sensation.

What clinical burn-assessment tool is shown here, and what body percentage is assigned to the back?

The Rule of Nines; the back represents $18\%$ of the total body surface area.

What type of abnormally large, firm scar resulting from collagen overproduction is shown here?

A keloid.

What is the difference between a furuncle and a carbuncle?

A furuncle is a localized pus-filled bacterial abscess around a single hair follicle, while a carbuncle is a cluster of several furuncles.

What condition presents with clusters of vesicles and crusts distributed unilaterally along a spinal dermatome as shown?

Shingles (caused by the varicella-zoster virus).

What are the common anatomical forms of tinea infections?

Tinea capitis (scalp/ringworm), tinea corporis (body), tinea cruris (groin), and tinea pedis (feet/athlete's foot).

What parasitic infestations correspond to lice and mites respectively?

Pediculosis is an infestation of parasitic lice and their nits (eggs), while scabies is an infestation of parasitic mites that tunnel under the skin.

What is urticaria, and what terms describe its characteristic lesions?

A localized allergic reaction causing sudden raised areas of erythema and edema due to food, plants, drugs, or stings; its lesions are commonly called hives, wheals, or welts.

What is actinic keratosis and why is it clinically concerning?

A raised, irregular, rough, sandpaper-like lesion caused by sun exposure in middle-aged persons (actin/o- = rays of the sun); it is premalignant and can progress to skin cancer.

What congenital vascular lesion presenting as a bright red, raised mass of dilated superficial vessels is shown?

Hemangioma.

What congenital condition involves the fusion of skin and soft tissue between adjacent digits?

Syndactyly.

What are the characteristics of basal cell carcinoma?

It is the most common form of skin cancer, arising in the basal layer of the epidermis, typically appearing as a raised pearly bump. It is slow-growing and does not metastasize.

What aggressive skin cancer of epidermal melanocytes is identified using the ABCDE diagnostic criteria?

Malignant melanoma.

What does each letter in the ABCDE acronym stand for when evaluating melanoma?

A = Asymmetry; B = Border (irregular/ragged); C = Color (varies from black/brown to pink/red/white); D = Diameter (greater than $6\text{ mm}$ or $\frac{1}{4}\text{ inch}$); E = Evolving (changing size, shape, or color).

What are the hallmarks of systemic lupus erythematosus (SLE) on the skin?

Deterioration of collagen in the skin and connective tissues, characteristically marked by a butterfly-shaped rash across the bridge of the nose and cheeks.

What is the difference between anhidrosis and diaphoresis?

Anhidrosis is a congenital absence of sudoriferous glands causing an inability to sweat or tolerate heat; diaphoresis is the process of sweating, which when excessive can signal serious conditions such as myocardial infarction or hypoglycemia.

What is onychomycosis?

A fungal infection of the fingernails or toenails that infects the nail root, causing nails to become deformed, thickened, and raised from the nail bed (onych/o- = nail, myc/o- = fungus, -osis = condition).

What diagnostic findings occur when vitiligo and tinea capitis are examined under a Wood lamp?

In a darkened room, ultraviolet light causes vitiligo to appear bright white and tinea capitis to fluoresce blue-green.

What is the source and mechanism of action of Botox injections?

Botox is a diluted neurotoxin from the bacterium Clostridium botulinum type A injected into facial muscles to relax deep wrinkle lines.

What is cryosurgery, and what agent is typically utilized?

A procedure in which liquid nitrogen is sprayed or painted onto benign or small malignant lesions to freeze and destroy the abnormal tissue.

What angle and skin layer correspond to a hypodermic needle injection as illustrated?

A $45^\circ$ angle, penetrating completely into the subcutaneous tissue.

What type of biopsy uses a circular metal instrument to excise a cylindrical tissue plug from the skin?

Punch biopsy.

What is Mohs surgery?

A surgical procedure for removing skin cancer (especially irregular or deep tumors) where excised tissue layers are systematically examined under an operating microscope during surgery until cancer-free margins are achieved.

What is a rhytidectomy, and what word parts form the term?

Surgical removal of wrinkles to tighten facial skin (a facelift), from rhytid/o- (wrinkle) and -ectomy (surgical removal).

What do the medical abbreviations C&S, I&D, and RAST stand for?

C&S = culture and sensitivity; I&D = incision and drainage; RAST = radioallergosorbent test.