Integumentary System Flashcards
what does the integumentary system consist of?
skin, hair, nails, sweat glands, sebaceous (oil) glands
regions of the skin
epidermis, dermis, hypodermis
epidermis
superficial; consists of epithelial tissue and is avascular
dermis
underlies the epidermis; mostly fibrous connective tissue; vascular-bleeding
hypodermis
superficial fascia; subcutaneous layer deep to the skin; not really skin; mostly adipose tissue that absorbs shock and insulates; anchors skin to underlying structures (mostly muscle)
cells of the epidermis
keratinocytes, melanocytes, dendritic (Langerhans) cells, and tactile (Merkel) cells
5 layers of the epidermis
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, stratum corneum
keratinocytes
- produce fibrous keratin
- major cells of the epidermis
- tightly connected by desmasomes
- millions slough off everyday
melanocytes
- spider-shaped cells in the deepest epidermis
-Produce pigment melanin, which is packaged into melanosomes which are transferred to keratinocytes, where they protect the nucleus from UV damage
dendritic (Langerhans) cells
-Star shaped macrophages that patrol deep epidermis
- key activators of the immune system
- clean up bacterium to keep it healthy
tactile (Merkel) cells
sensory receptors that sense touch
stratum basale
- deepest layer firmly attached to the dermis
- single row of stem cells that actively divide (mitotic)
- one daughter cell stays, the other goes to the surface and dies as it moves up
- 10-25% melanocytes
stratum spinosum
- prickly layer that is several layers thick
- weblike system of intermediate prekeratin filaments attached to desmosomes (allows them to resist tension and pulling)
- scattered among keratinocytes are abundant desmosomes and dendritic cells
stratum granulosum
- 4-6 cells thick (flattened so its a thin layer)
- cell apearance changes: cells flatten, nuclei and organelles disintegrate
- keratinization begins
- cells accumulate lamellar granules (water resistent glycolipid that slows water loss)
- cells above this layer die bc they’re too far from capillaries
stratum lucidum
- clear layer
- found only in thick skin
- 2-3 rows of clear flat dead keratinocytes
- lies superficial to stratum granulosum
stratum corneum
- horny layer
- 20-30 rows of flat anucleated keratinized dead cells
- 3/4 of epidermal thickness
- Protect deeper cells form environment
- Prevent water loss
- Protect from abrasion and penetration
- Acts as barrier against biological, chemical, and physical assaults.
dermis
- strong flexible connective tissue
- cells include fibroblasts, and occasionally mast cells and WBCs
- contains nerves, blood vessels, and lymphatic vessels
- contains epidermal hair follicles, oil glands, and sweat glands
- 8-10x thicker than the epidermis
- papillary layer and reticular layer
papillary layer of the dermis
- superficial layer of areolar connective tissue
- contains friction ridges
- contains dermal papillae
reticular layer of the dermis
- 80% of dermal thickness
- consist of course dense fibrous connective tissue
- cutaneous plexus: network of blood vessels
- extracellular matrix contains pockets of adipose tissue
- cleavage lines
- flexure lines
cleavage lines
caused by many collogen fibers running parallel to skin surface; incisions parallel to cleavage lines heal better
flexure lines
dermal folds at or near joints
straie
stretch marks caused by dermal tears
3 pigments that contribute to skin color
melanin, carotene, hemoglobin
melanin
- made by melanocytes
- reddish yellow or brownish black
- skin colot differences due to amount and form of melanin
carotene
- yellow to orange pigment
- most obvious in palms and soles
- accumulates in stratum corneum and hypodermis
- can be converted to vitamin A for vision and epidermal health
hemoglobin
- pinkish hue of fair skin is due to lower levels of melanin
- skin of Caucasians is more transparent, so color of hemoglobin shows through
cyanosis
Blue skin color: low oxygenation of hemoglobin
pallor
Anemia, low blood pressure, fear, anger
erythema
redness; Fever, hypertension, inflammation, allergy
jaundice
yellow; Liver disorders
bruises
Also referred to as ecchymoses or hematomas, are a result of clotted blood beneath skin
brown/black necklace bruises
- hyperpigmented dark areas in axillae and around neck may be a sign of insulin resistance and elevated blood glucose levels
- immediate referral
functions of hair
- Warn of insects on skin
- Hair on head guards against physical trauma
- Protect from heat loss
- Shield skin from sunlight
shaft of hair
area that extends above scalp, where keratinization is complete
root of hair
area within scalp, where keratinization is still going on
medulla of the hair shaft
central core of large cells and air spaces
cortex of the hair shaft
several layers of flattened cells surrounding medulla
cuticle of the hair shaft
outer layer consisting of overlapping layers of single cells
hair pigments
Combinations of different melanins (yellow, rust, brown, black) create all the hair colors
red hair
additional pheomelanin pigment
gray hair
results when melanin production decreases and air bubbles replace melanin in shaft
hair bulb
expanded area at deep end of follicle
hair follicle receptor
sensory nerve endings that wrap around bulb
hair matrix
actively dividing area of bulb that produces hair cells
arrector pilli
small band of smooth muscle attached to follicle; responsible for “goose bumps”
hair papilla
Dermal tissue containing a knot of capillaries that supplies nutrients to growing hair
vellus hair
pale, fine body hair of children and adult females
terminal hair
course long hair
PCOS
tumors of adrenal glands that causes excess androgens
telogen effluvium
abrupt hair thinning caused by an abundance of hair follicles entering resting phase at same time; can be caused stress, hormonal changes, surgery, trauma, crash dieting, etc.
causes of hair changes
Drugs (ex: antidepressants, chemotherapeutic drugs)
Hypothyroidism
Protein-deficient diets
Hyperthyroidism can also cause hair loss
nails
Scale-like modifications of epidermis that contain hard keratin
parts of nails
free edge, nail plate, and root
nail bed
epidermis underneath keratinized nail plate
nail matrix
thickened portion of bed responsible for nail growth
nail folds
skin folds that overlap border of nail
eponychium
nail fold that projects onto surface of nail body (cuticle)
hyponychium
area under free edge of plate that accumulates dirt
lunule
thickened nail matrix, appears white
yellow-tinged nails
may indicate respiratory or thyroid gland disorder
Koilonchya
also called “spoon nail” – an outward concavity of nail may signal iron deficiency
Beau’s lines
horizontal lines across nails may indicate severe illnesses such as uncontrolled diabetes, heart attack or cancer chemotherapy
eccrine (merocrine) glands
palms, soles, and forehead; ducts connect to pores; thermoregulation
apocrine sweat glands
axillary and anogenital areas; begin at puberty; viscous milky or yellowish sweat
modified apocrine glands
- Ceruminous glands: lining of external ear canal; secrete cerumen (earwax)
- Mammary glands: secrete milk
sebaceous (oil) glands
Widely distributed, except for thick skin of palms and soles; most develop from hair follicles and secrete into hair follicles; relatively inactive until puberty
functions of skin
protection, body temp regulation, cutaneous sensations, metabolic functions(synthesize vit D for calcium absorption), blood reservoir, and excretion of wastes
insensible perspiration
Under normal, resting body temperature, sweat glands produce about 500 ml/day of unnoticeable sweat
sensible perspiration
If body temperature rises, dilation of dermal vessels can increase sweat gland activity to produce 12 L (3 gallons) of noticeable sweat
skin protection mechanism
chemical barrier, biological barrier, and physical barrier
basal cell carcinoma
Least malignant and most common
Stratum basale cells proliferate and slowly invade dermis and hypodermis
Cured by surgical excision in 99% of cases
squamous cell carcinoma
Second most common type; can metastasize
Involves keratinocytes of stratum spinosum
Usually is a scaly reddened papule on scalp, ears, lower lip, or hands
Good prognosis if treated by radiation therapy or removed surgically
melanoma
Cancer of melanocytes; is most dangerous type because it is highly metastatic and resistant to chemotherapy
Treated by wide surgical excision accompanied by immunotherapy
ABCD rule
A: asymmetry; the two sides of the pigmented area do not match
B: border irregularity; exhibits indentations
C: color; contains several colors (black, brown, tan, sometimes red or blue)
D: diameter; larger than 6 mm (size of pencil eraser)
immediate threat with burns
dehydration and electrolyte imbalance
the rule of nines
divides the body into 11 sections with each section representing 9% (except genitals, which account for 1%)
superficial burns
epidermal damage only; localized redness, edema, and pain
superficial partial thickness/deep partial thickness
epidermal and upper dermal damage; blister appear; 1st and 2nd degree burns
full thickness burns
entire thickness of skin is involved through the subcutaneous tissues; skin turns gray-white, cherry-red, or blackened; no edema and no pain bc nerve ending are destroyed; skin grafting usually necessary; 3rd degree burns
burns are critical if:
> 20% of body has deep-partial thickness burns
> 10% of body has full thickness burns
Face, hands, or feet bear full thickness burns
lanugo coat
delicate hairs in 5th and 6th month
vernix caseosa
sebaceous gland secretion that protects skin of fetus while in watery amniotic fluid
aging skin
Epidermal replacement slows; skin becomes thin, dry, and itchy (decreased sebaceous gland activity)
Subcutaneous fat and elasticity decrease, leading to cold intolerance and wrinkles
Increased risk of cancer due to decreased numbers of melanocytes and dendritic cells
Hair thinning
Bringing new cells up doesn’t happen as rapidly partially bc sebaceous glands don’t work as much anymore.
Less thermal insulation as you age.
