Ch 5. The Integumentary System Flashcards
Composed of epithelial cells, it is the outermost protective shield of the body
Epidermis
This layer makes up the bulk of the skin and is a tough, leathery layer composed mostly of dense connective tissue
Dermis
The subcutaneous tissue just deep to the skin that anchors the skin to the underlying structures (mostly muscles) but allows the skin to slide relatively freely over the structures
Hypodermis (superficial fascia)
Cells that undergo almost continuous mitosis in response to prompting by epidermal growth factor. They are located in the stratum basale
Keratinocytes
The fibrous protein that helps give the epidermis its protective properties
Keratin
Thickening of the epidermis
Callus
The spider-shaped epithelial cells that synthesize the pigment melanin and are found in the deepest layer of the epidermis
Melanocytes
Star-shaped cells that arise from bone marrow and migrate to the epidermis. They ingest foreign substances and are key activators of our immune system
Dendritic cells (Langerhans cells)
Cells that are shaped like a spiky hemisphere and is associated with a disc-like sensory nerve ending. They are present at the epidermal junction
Tactile (Merkel) cells
The deepest epidermal layer that is attached to the underlying dermis along a wavy borderline that resembles corrugated cardboard.
Stratum Basale (Stratum Germinativum)
An epidermal layer that is several cell layers thick and contains a weblike system of intermediate filaments
Stratum Spinosum (prickly)
A thin epidermal layer in which keratinocyte appearance changes drastically, and the process of keratinization begins
Stratum Granulosum
One type of granule located in the stratum granulosum that helps to form keratin in the upper layers
Keratohyaline granules
One type of granule located in the stratum granulosum that contains a water-resistent glycolipid that is spewed into the extracellular space
Lamellar granules
An epidermal layer only visible in thick skin that is composed of a translucent band just above the stratum granulosum
Stratum Lucidum
The outermost epidermal layer is a broad zone 20 to 30 cell layers thick that accounts for up to three-quarters of the epidermal thickness
Stratum Corneum
The shingle-like cell remnants of the stratum corneum
Horny cells
The thin, superficial layer of the dermis that is made up of areolar connective tissue
Papillary layer
Peglike projections from the surface of the papillary layer
Dermal papillae
In thick skin, papillae lie atop larger mounds called…
Dermal ridges
Skin ridges that enhance the gripping ability of the fingers and feet l
Friction ridges (epidermal ridges)
The course layer of the dermis made up of dense irregular connective tissue that accounts for about 80% of the dermis
Reticular layer
Separations, or less dense regions between bundles of collagen fibers form…
Cleavage (tension) lines
Dermal folds that occur at or near joints where the dermis is tightly secured to deeper structures
Flexure lines
A polymer made of tyrosine amino acids that determines skin color
Melanin
A yellow to orange pigment found in certain plant products such as carrots. It accumulates in the stratum corneum and in fatty tissue of the hypodermis
Carotene
Oxygenated pigment located in red blood cells that circulates through the dermal capillaries
Hemoglobin
When the skin appears blue due to poorly oxygenated hemoglobin
Cyanosis
Includes hair and hair follicles, nails, sweat glands, and sebaceous (oil) glands
Skin appendages
Flexible strands produced by hair follicles and consist largely of dead, keratinized cells
Hairs (pili)
The central core of the hair bulb that consists of large cells, air spaces and contains soft keratin
Medulla
The bulky layer of the hair bulb that consists of several layers of flattened cells and surrounds the medulla
Cortex
The outermost layer of the hair bulb that is formed from a single layer of cells overlapping one another
Cuticle
Folds down from the epidermal surface into the dermis
Hair follicles
A knot of sensory nerve endings that wraps around each hair bulb
Hair follicle receptor (root hair plexus)
The outer part of the hair follicle wall
Peripheral connective tissue sheath
The thickened basal lamina of the wall of the hair follicle
Glassy membrane
The inner layer of the hair follicle wall derived mainly from the invagination of the epidermis
Epithelial root sheath
Actively dividing area of the hair bulb that produces the hair
Hair matrix
A bundle of smooth muscle cells, “raiser of hair”
Arrector pili
Pale, fine hair found in children and adult females
Vellus hair
The coarser, longer hair of the eyebrows and scalp
Terminal hair
Excessive hairiness
Hirsuitism
Hair thinning or some degree of baldness
Alopecia
Genetically determined, sex-influenced condition that causes baldness
Male pattern baldness
A condition in which the immune system attacks the follicles and the hair falls out in patches
Alopecia areata
The thickened proximal portion of the nail bed
Nail matrix
Proximal and lateral borders of the nail are overlapped by skin folds
Nail folds
The part of the nail where the proximal nail fold projects onto the nail body
Cuticle (eponychium)
The thickened region beneath the free edge of the nail where dirt and debris tend to accumulate
Hyponychium
The type of glands that are distributed all over the entire skin surface except the nipples and parts of the external genitalia
Sweat (sudoriferous) glands
Sweat glands that are particularly abundant on the palms, soles of the feet, and forehead
Eccrine sweat glands (merocrine)
Sweat glands that are largely confined to the axillary and anogenital areas
Apocrine sweat glands
Modified apocrine glands found in the lining of the external ear canal
Ceruminous glands
A type of specialized sweat glands that secrete milk
Mammary glands
Simple branched alveolar glands that are found all over the body except in the thick skin of the palms and soles
Sebaceous glands (oil glands)
Secretion of sebaceous glands
Sebum
The low pH of skin secretions
Acid mantle
Natural antibiotics that skin cells secrete
Defensins
Protective peptides that sounded skin releases
Cathelicidins
Routine and unnoticeable sweating
Insensible perspiration
Visible output of sweat
Sensible perspiration
Exteroceptors that respond to stimuli arising outside the body and are supplied richly in the skin
Cutaneous sensory receptors
The least malignant and most common type of skin cancer, that accounts for nearly 80% of cases
Basal cell carcinoma
The second most common skin cancer that arises from keratinocytes of the stratum spinosum
Squamous cell carcinoma
Cancer of the melanocytes; the most dangerous skin cancer because it is highly metstastic and resistant to chemotherapy
Melanoma
Tissue damage inflicted by intense heat, electricity, radiation, or certain chemicals, all of which denature cell proteins and kill cells in the affected areas
Burn
The volume of fluid lost can be estimated by computing the percentage of body surface burned using this rule
Rule of nines
Only the epidermis is damaged in this type of burn
First-degree burns
These burns injure the epidermis and the upper region of the dermis. Blisters appear and the area is red and painful but the skin will regenerate in 3-4 weeks
Second-degree burns (partial-thickness)
These burns involve the entire thickness of the skin. It appears gray-white, cherry red, or blackened and initially there is little or no edema. Nerve endings have been destroyed and skin grafting is advised.
Third-degree burns (full-thickness)
Burned skin
Eschar
A downy coat of delicate, colorless hairs that covers a fetus during the fifth and sixth months and is shed by the seventh month
Lanugo coat
Scaling and various kinds of skin inflammation
Dermatitis
