Chapter 5 Integumentary System

epidermis

Superficial layer of the skin; composed of keratinized stratified squamous epithelium

dermis

the deep layer of the skin; composed of dense, irregular connective tissue

Hypodermis (subcutaneous layer)

Deep to the dermis; not technically part of the skin; made of adipose tissue; helps insulate

Pancinian corpuscles

Composed of connective tissue and cells that detect deep pressure and vibrations

keratinocytes

an epidermal cell that produces keratin.

melanocytes

cells that produce melanin

Merkel cells

cells of the epidermis that play a role in transmission of sensory messages

Langerhans cells

epidermal macrophages that help activate the immune system

thin skin

Type of skin that lacks a stratum lucidum, has hair, and is found covering most of the body

thick skin

The skin type on the palms and soles is characterized by the absence of hair follicles and presence of stratum lucidum

stratum basale (germinativum)

base layer of skin, one cell layer, always under division

stratum spinosum

layer of the epidermis superficial to the stratum basale, characterized by the presence of desmosomes

stratum granulosum

a layer of the epidermis that marks the transition between the deeper, metabolically active strata and the dead cells of the more superficial strata

stratum lucidum

Clear, transparent layer of the epidermis under the stratum corneum.

stratum corneum

outermost layer of the epidermis, which consists of flattened, keratinized (dead) cells

isograft

transplant between identical twins

xenograft (heterograft)

transplantation (dermis only) from a foreign donor (usually a pig) and transferred to a human

autograft

transplantation of healthy tissue from one site to another site in the same individual

callus

increased growth of cells in the stratum corneum layer of the epidermis caused by pressure or friction

keratinization

process of cells accumulating keratin as they move superficially; eventually die & slough off- then replaced by new cells; takes 4 weeks

Epidermal Growth Factor (EGF)

Stimulates cells to reproduce and heal.

dandruff

excess of keratinized cells shed from the scalp

Psoriasis

chronic skin condition producing red lesions covered with silvery scales from abnormal keratinization

papillary layer

Top 1/5 of dermis, most is areolar connective tissue, dermal papillae "fingerprints"

reticular layer

Bottom 4/5 of the dermis, most is dense irregular connective tissue.

lines of cleavage (tension lines)

The bundles of collagen and elastin fiber in the dermis align themselves parallel to the direction of routine movement; this orientation of fiber bundles creates -- of ---.

Should be considered in surgical procedures to allow for healing and prevention of scarring.

epidermal ridges

downward projections of the epidermis into the dermis, create fingerprints

melanin

a dark brown to black pigment occurring in the hair, skin, and iris of the eye in people and animals. It is responsible for tanning of skin exposed to sunlight.

nevus

mole

hemoglobin

An iron-containing protein in red blood cells that reversibly binds oxygen. Gives skin a pink color.

Carotene

Yellow to orange pigment that accumulates in the stratum corneum epidermal layer and in fatty tissue of the hypodermis

Albinism

an inherited deficiency or absence of pigment in the skin, hair and irises due to a missing enzyme (tyrosinase) necessary for the production of melanin

cyanosis

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

vitiligo

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

pallor

extreme paleness, lack of blood in the skin so can see the collagen in the skin

jaundice

yellowing of the skin and the whites of the eyes caused by an accumulation of bile pigment (bilirubin) in the blood from a disfunctional liver

Tattooing

a permanent coloration of the skin in which a foreign pigment is deposited with a needle into the dermis

shaft

visible part of the hair

root

part of the hair enclosed in the follicle under the skin

bulb

the base of a hair follicle and its surrounding dermal root sheath, containing the papilla of the hair and matrix

hair matrix

actively dividing area of the hair bulb that produces the hair

arrector pili

a smooth muscle attached to hair follicles that causes "goose bumps" to appear on the skin when contracted

hair root plexus

a collection of dendrites of neurons surrounding each hair follicle that are sensitive to touch

alopecia

hair loss

lanugo

fine, soft hair, especially that which covers the body and limbs of a human fetus or newborn.

vellus hair

pale, fine body hair of children and adult females

terminal hair

Long, coarse, pigmented hair found on the scalp, legs, arms, and bodies of males and females.

hirsutism

excessive hair growth

sebaceous glands

oil glands in the skin

sudoriferous glands

glands that secrete sweat to the outside of the body; also assist in body temperature regulation

ceruminous glands

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

mammary glands

modified sweat apocrine sweat glands that produce milk

eccrine (merocrine) glands

glands that produce sweat; found over most of the body

apocrine glands

Sweat glands in the pubic and underarm areas that secrete thicker sweat, that produce odor when come in contact with bacteria on the skin

nail bed

Portion of the living skin that supports the nail plate as it grows toward the free edge.

free edge of nail

the portion of the nail that grows out away from the body

nail matrix

the part of the nail beneath the body and root from which the nail is produced

eponychium (cuticle)

narrow zone of dead skin overhanging proximal end of nail

hypochium

thickened region beneath the free edge of the nail where dirt and debris tend to accumulate

contact inhibition

the cessation of cell division in response to contact with other cells

inflammatory phase

the initial phase of wound healing in which bleeding is reduced as blood vessels in the affected area constrict

migratory phase

epithelial cells migrate to bridge the wound

proliferative phase

characterized by extensive growth of epithelial cells beneath the scab, deposition by fibroblasts of collagen fibers in random patterns, and continued growth of blood vessels

maturation phase

the stage in wound healing where a scab sloughs off once the epidermis has been restored to its normal thickness

basal cell carcinoma

Most common and least severe type of skin cancer; often characterized by light or pearly nodules. Originates in the stratum basale

squamous cell carcinoma

Type of skin cancer more serious than basal cell carcinoma; often characterized by scaly red papules or nodules. Originates in the stratum spinosum

malignant melanoma

Most serious form of skin cancer; often characterized by black or dark brown patches on the skin that may appear uneven in texture, jagged, or raised.

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.

1st degree burn

Only the epidermis is damaged (red, painful, and edema)

2nd degree burn

The epidermis and part of dermis (blistered) have been damaged

3rd degree burn

Full thickness damage through all layers of the skin into nerves and muscles

pressure ulcer

erosion of the skin caused by prolonged pressure, often occurring in bedridden patients