The Integumentary System - Terminology

epidermis

outermost layer of skin

dermis

middle layer of skin; innervated and vasculated

hypodermis

the layer of skin beneath the dermis, which serves as a storage repository for fat

keratin

hard protein material found in the epidermis, hair, and nails

melainin

brown, yellow-brown, or black pigment produced by melanocytes

tactile cells (merkel cells)

sensory touch receptors

stratum basale (germinativum)

deepest, mitotic layer of the epidermis

stratum spinosum (prickly Layer)

second deepest layer of the epidermis; 7-10 layers of cells, mostly keratinocytes with a few langerhans cells and some melanin granules

stratum granulosum (granular layer)

third layer from the bottom of the epidermis; composed of cells that look like granules and are filled with keratin; replaces cells shed from stratum corneum

stratum lucidum (clear layer)

only in thick skin; thin, translucent band superficial to the stratum granulosum

A few rows of flat, dead keratinocytes

stratum corneum (horny layer)

uppermost layer of the epidermis; 20 to 40 cell layers of dead, flat keratinized cells, accounts for up to 3/4s of epidermal thickness.

dermal papillae

a fingerlike projection of the dermis that may contain blood capillaries or Meissner corpuscles (of touch)

cleavage lines (tension lines)

many collagen fibers running parallel to skin surface; important to surgeons because incisions parallel to cleavage lines heal more readily

straie

stretch marks made in the collagen fibers of the dermis layer

blister

a bubble-like collection of fluid beneath or within the epidermis of the skin

cyanosis

a bluish discoloration of the skin resulting from poor circulation or inadequate oxygenation of the blood.

pallor (blanching)

pale color due to anemia, low blood pressure, fear, anger

erythemia

redness of the skin; may indicate fever, hypertension, inflammation, or allergy

juandice

yellowing of the skin, can indicate bile in the blood as a result of liver or gallbladder disease

bruise

Also referred to as ecchymoses or hematomas, are a result of clotted blood beneath skin

vellus hair

pale, fine hair

terminal hair

long, coarse, pigmented hair found on the scalp, legs, arms, and bodies

hirsutism

excessive hair growth

alopecia

hair thinning in both sexes after age 40

ingrown hair

a hair that curls into the side wall of the hair follicle or into the skin surface, which causes the skin to become inflamed.

ingrown nail

painful condition in which the corner or side of a toenail grows into the soft flesh of that toe

pimple

also known as papule; small elevation on the skin that contains no fluid but may develop pus.

acne

inflammatory disease of the skin involving the sebaceous glands and hair follicles

suderiferous glands

sweat glands

eccrine or merocrine sweat glands

secreting glands, are far more numerous and are abundant on palms, soles of feet and forehead.

apocrine sweat glands

produce true sweat plus fatty substances and proteins; found in the axillary and anogenital areas of the body

ceruminous glands

modified sweat glands, located in external ear canal, secretes cerumen (earwax)

mammary glands

specialized organs in mammals that produce milk to nourish the young

sebum

oily substance secreted by sebaceous glands

sebaceous glands

secrete sebum (oil) into the hair follicles where the hair shafts pass through the dermis

basal cell carcinoma

a malignant tumor of the basal cell layer of the epidermis; this is the most common and least harmful type of skin cancer because it is slow growing and rarely spreads to other parts of the body

squamous cell carcinoma

type of skin cancer more serious than basal cell carcinoma; often characterized by scaly red papules or nodules.

melanoma

cancer of melanocytes; is most dangerous type because it is highly metastatic and resistant to chemotherapy

epidermoid cyst

occurs when keratin builds up under the skin layers and forms a cyst filled with a cheesy material composed of sebum and epithelial debris

first degree burn

superficial burns through only the epidermis.

second degree burn

a burn marked by pain, blistering, and superficial destruction of dermis

third degree burn

a burn involving all layers of the skin; characterized by the destruction of the epidermis and dermis, with damage or destruction of subcutaneous tissue

debridement

removal of foreign matter or dead tissue from a wound

rule of nines

a system that assigns percentages to sections of the body, allowing calculation of the amount of skin surface involved in the burn area.

skin boil

a painful, pus-filled bump under the skin caused by infected, inflamed hair follicles.

wart

a firm abnormal elevated blemish on the skin caused by a virus

cold sores

an inflamed blister in or near the mouth, caused by infection with the herpes simplex virus.

hives

Red, itchy, possibly raised blotches on the skin that often result from allergic reactions

actinic keratosis

a precancerous skin growth that occurs on sun-damaged skin

rosacea

Chronic skin disorder of the face with red inflamed areas appearing mostly on the nose and cheeks

eczema

noninfectious, inflammatory skin disease characterized by redness, blisters, scabs, and itching

psoriasis

chronic, recurrent dermatosis marked by itchy, scaly, red plaques covered by silvery gray scales

vitiligo

white patches on the skin caused by the destruction of melanocytes associated with autoimmune disorders

warts

growths on your skin caused by an infection with human papilloma virus, or HPV

ringworm

infection caused by the fungus tinea characterized by red, blotchy patches

Impetigo

bacterial skin infection characterized by isolated pustules that become crusted and rupture

albinism

congenital hereditary condition characterized by partial or total lack of pigment in the skin, hair, and eyes