Chapter 5 Flashcards
integumentary system
consists of the skin and accessory structures, such as hair, glands, and nails.
epidermis
Superficial part of skin; stratified squamous epithelium;
composed of four or five strata. Prevents water loss and the entry of chemicals and microorganisms; protects against abrasion and ultraviolet light; produces vitamin D; gives rise to hair, nails, and glands and reduces water loss through the skin.
dermis
Deep part of skin; connective tissue composed of two layers. Is responsible for the structural strength and flexibility of the skin; the epidermis exchanges gases, nutrients, and waste products with blood vessels in the dermis
subcutaneous tissue or hypodermis
Not part of the skin; loose connective tissue with abundant
deposits of adipose tissue. Attaches the dermis to underlying structures; adipose tissue provides energy storage, insulation, and padding; blood vessels
and nerves from the subcutaneous tissue supply the dermis
keratinocytes
what most cells of the epidermis are called because
they produce a protein mixture called keratin, which
makes the cells more durable; give the epidermis its ability to resist abrasion and reduce water loss.
melanocytes
contribute to skin color; irregularly shaped cells with many long processes that extend between the keratinocytes of the stratum basale and the stratum spinosum
Langerhans cells
part of the immune system
Merkel cells
specialized epidermal cells associated with nerve endings responsible for detecting light touch and superficial pressure
keratinization
cells become filled with keratin as they move toward the surface and eventually die and produce an outer layer of dead, hard cells that resists abrasion and forms a
permeability barrier.
psoriasis
skin condition where large scales of epidermal tissue are sloughed off
strata
the regions of which the many layers of cells in the epidermis are divided
stratum basale or stratum germinativum
Deepest stratum of the epidermis; single layer of cuboidal or columnar cells; basement membrane of the epidermis attaches to the dermis.Produces cells of the most superficial strata; melanocytes produce and contribute melanin, which protects against ultraviolet light
stratum spinosum
A total of 8–10 layers of many-sided cells. Produces keratin fibers; lamellar bodies form inside keratinocytes
lamellar bodies
lipid-filled membrane-bound organelles that form inside the keratinocytes.
stratum granulosum
Two to five layers of flattened, diamond-shaped cells. Produces keratohyalin granules; lamellar bodies release lipids from cells; cells die
keratohyalin
nonmembrane-bound protein granules which accumulate in the cytoplasm of the cell.
Stratum corneum
Most superficial stratum of the epidermis; 25 or more layers of dead squamous cells. Provides structural strength due to keratin within cells; prevents water loss due to lipids surrounding cells; sloughing off of most superficial cells resists abrasion
Stratum lucidum
Three to five layers of dead cells; appears transparent; present in thick skin, absent in most thin skin. Disperses keratohyalin around keratin fibers
cornified cells
stratum corneum consists of cornified cells, which are
dead cells, with a hard protein envelope, filled with the protein keratin.
Thick skin
has all 5 epithelial strata, and the stratum corneum
has many layers of cells; found in areas subject to pressure or friction, such as the palms of the hands, the soles of the feet, and the fingertips.
thin skin
covers the rest of the body and is more flexible than thick skin.
callus
the number of layers in the stratum corneum greatly increases to produce a thickened area in skin subjected to friction or pressure
corn
skin over bony prominences may develop this cone-shaped structure
Melanin
group of pigments primarily responsible for skin, hair, and eye color; provides protection against ultraviolet light from the sun.
melanosomes
Golgi apparatuses of the melanocytes package melanin into vesicles called melanosomes, which
move into the cell processes of the melanocytes.
Basal cell carcinoma
the most common type of skin cancer, affects cells in the stratum basale. Some are open sores that bleed, ooze, or crust for several weeks. Others are reddish patches; shiny, pearly, or translucent bumps; or scarlike areas of shiny, taut skin.
actinic keratosis
a small, scaly, crusty bump that arises on the surface of the skin. If untreated, about 2–5% of actinic keratoses can progress to squamous cell carcinoma
squamous cell carcinoma
second most common type of skin cancer. Squamous cell carcinoma affects cells in the stratum spinosum and can appear as a wartlike growth; a persistent, scaly red patch; an open sore; or an elevated growth with a central depression.
Melanoma
least common, but most deadly, type of skin cancer; arise
from melanocytes, so most melanomas are black or brown, but can appear skin-colored, pink, red, or purple
ABCDE rule
signs of melanoma: A - asymmetry (one side of the lesion does not match the other side), B - border irregularity (the edges are ragged, notched, or blurred), C - color (pigmentation is not uniform), D - diameter (greater than 6 mm), and E - evolving (lesion changes over time).
Xeroderma pigmentosum
rare, autosomal recessive trait in which a DNA repair gene is defective.
Albinism
recessive genetic trait that results from an inability to produce tyrosinase. The result is a deficiency or an absence of pigment in the skin, hair, and the irises of the eyes.
erythema
a condition when blood flowing through the skin imparts a reddish hue
cyanosis
A decrease in blood flow, as occurs in shock, can make the skin appear pale, and a decrease in the blood oxygen content produces a bluish skin color
Carotene
yellow pigment found in plants; when large consumed, the excess accumulates in the stratum corneum and in adipocytes of the dermis and subcutaneous tissue, causing the skin to develop a yellowish tint.
dermal papillae
projections in the papillary layer of the dermis that extend toward the epidermis.
papillary layer
loose connective tissue with thin fibers that are loosely arranged; contains blood vessels that supply the overlying epidermis with nutrients, remove waste products, and aid in regulating body temperature.
reticular layer
composed of dense irregular connective tissue; main layer of the dermis; continuous with the subcutaneous tissue and forms a mat of irregularly arranged fibers that are resistant to stretching in many directions.
cleavage lines or tension lines
The elastic and collagen fibers are oriented more in some directions than in others and produce these lines in the skin
stretch marks
if the skin is overstretched, the dermis may rupture and leave lines of scar tissue that are visible through the epidermis
intradermal injection
used for the tuberculin skin test, goes into the dermis.
subcutaneous injection
subcutaneous injection extends into the subcutaneous tissue; an insulin injection; tent pinch
intramuscular injection
reaches a muscle deep to the subcutaneous tissue; long needle at 90 degrees
lanugo
By the fifth or sixth month of fetal development, this delicate, unpigmented hair has developed and covered the fetus.
terminal hairs
Near the time of birth, these hairs, which are long, coarse, and pigmented, replace the lanugo of the scalp, eyelids, and eyebrows.
vellus hairs
short, fine, and usually unpigmented, replace the lanugo on the rest of the body.
hair bulb
The base of the root is expanded to form the hair bulb.
medulla
central axis of the hair; it consists of two or three layers of cells containing soft keratin.
cortex
forms the bulk of the hair; it consists of cells containing hard keratin; covered by the cuticle
cuticle
a single layer of cells that contain hard keratin. The edges of the cuticle cells overlap like shingles on a roof.
dermal root sheath
portion of the dermis that surrounds the epithelial root sheath.
epithelial root sheath
divided into external and internal parts; At the opening of the follicle, the external epithelial root sheath has all the strata found in thin skin. internal epithelial root sheath has raised edges that mesh closely with the raised edges of the hair cuticle and hold the hair in place. When a hair is pulled out, the internal epithelial root sheath usually comes out as well and is plainly visible as whitish tissue around the root of the hair.
matrix
Inside the hair bulb is this mass of undifferentiated epithelial cells, which produces the hair and the internal epithelial root sheath.
hair papilla
dermis of the skin projects into this hair bulb; it contains blood vessels that provide nourishment to the cells of the matrix.
arrector pili
smooth muscle cells associated with each hair follicle, which extend from the dermal root sheath of the hair follicle to the papillary layer of the dermis
Sebaceous glands
located in the dermis; simple or compound alveolar glands that produce sebum, an oily, white substance rich in lipids.
sweat glands or sudoriferous glands
2 types - eccrine glands (most common; simple, coiled, tubular glands that open directly onto the surface of the skin through sweat pores) and apocrine glands (simple, coiled, tubular glands that open into hair follicles superficial to the opening of the sebaceous glands; found in armpits, genitals; puberty sweat glands; do not help regulate temp)
Partial-thickness burns
subdivided into first- and second-degree burns.
First-degree burns
involve only the epidermis and may result in redness, pain, and slight edema (swelling).
Second-degree burns
damage the epidermis and the dermis.
Full-thickness burns or third-degree burns
epidermis and dermis are completely destroyed, and deeper tissue may be involved.
major burn
a third-degree burn over 10% or more of the BSA; a second-degree burn over 25% or more of the BSA; or a second- or third-degree burn of the hands, feet, face, genitals, or anal region.
moderate burn
third-degree burn over 2–10% of the BSA or a second-degree burn over 15–25% of the BSA
minor burn
third-degree burn over less than 2% or a second-degree burn over less than 15% of the BSA.
ceruminous glands
modified eccrine sweat glands located in the ear canal
cerumen
earwax; composed of the combined secretions of ceruminous glands and sebaceous glands.
mammary glands
modified apocrine sweat glands located in the breasts; produce milk.
nail
thin plate, consisting of layers of dead stratum corneum cells that contain a very hard type of keratin.
nail root
covered by skin
nail body
visible portion of the nail.
nail fold
skin that covers the lateral and proximal edges of the nail
nail groove
skin that holds the nail edges in place
cuticle or eponychium
stratum corneum of the nail fold that grows onto the nail body
hyponychium
Beneath the free edge of the nail body is this thickened
region of the stratum corneum
nail bed
located between the nail matrix and the hyponychium; composed of epithelial tissue, with a stratum basale that gives rise to the cells that form the nail.
nail matrix
nail root extends distally from matrix; composed of epithelial tissue, with a stratum basale that gives
rise to the cells that form the nail.
lunula
A small part of the nail matrix, that is seen through the nail body as a whitish, crescent-shaped area at the base of the nail.
Vitamin D
Skin exposed to ultraviolet light produces cholecalciferol, which is modified in the liver and then in the kidneys to form active vitamin D; functions as a hormone to stimulate the uptake of calcium and phosphate from the intestines, to promote their release from bones, and to reduce calcium loss from the kidneys, resulting in increased blood calcium and phosphate levels.
Debridement
the removal of dead tissue from the burn, helps prevent
infection by cleaning the wound and removing tissue in which infection could develop.
