Chapter 6 (test 2) Flashcards
dermatology
study and medical treatment of the integumentary system
exfoliate
the removal of dead skin cells (keratinocytes)
callus/corns
thick accumulation of dead keratinocytes on hands or feet
dander
dead cells on the scalp
dandruff
clumps stuck together of dander
dermal papillae
upward fingerlike extensions of dermis
-only source of nutrition for the hair
stretch marks
tears in collagen fibers caused by the stretching of skin
- occurs in the reticular layer of the dermis
hemoglobin
part of the blood that carries oxygen
carotene
yellow pigment from egg yolks and yellow/orange veggies
friction ridges
finger prints
freckles
flat, melanized patches
moles
elevated melanized patches often with hair
pilus
another name for hair
-pili (plural)
hair
slender filament of keratinized cells growing from an oblique tube in the skin (hair follicle)
hair follicle
oblique tube in the skin
hair receptors
nerve fibers in hair follicle
aloplecia
thinning of hair or baldness
pattern baldness
condition when hair loss occurs from specific regions of the scalp
bromhidrosis
disagreeable body odor produced by bacterial action on fatty acid
acid mantle
inhibits bacterial growth
insensible perspiration
no visible wetness of skin
diaphoresis
sweating with wetness of skin
holocrine gland
secretion of broken down cells
-mitosis replaces at base of gland
eschar
burned dead tissue
-toxic if not removed from skin
components of integumentary system
skin, hair, nails, cutaneous gland
layers
epidermis and dermis
epidermis
top layer of skin
- 5 types of cells
- stem cells
- keratinocytes
- melanocytes
- tactile(merkel) cells
- dendritic(langerhans) cells
layers of epidermis
stratum corneum stratum lucidum stratum granulosum stratum spinosum stratum basale
stratum corneum
up to 30 layers
surface cells flake off
resists abrasion, penetration and water loss
stratum lucidum
only in thick skin
thin translucent zone(dead cells)
cells with no nucleus or other organelles
stratum granulosum
3-5 layers of flat cells
dark staining coarse
stratum spinosum
several layers of cells
deepest layer is capable of mitosis
keratin filaments=flattens cell
stratum basale
1 layer stem cells and keratinocytes on basement membrane
- melanocyte and tactile cells also present
- replaces lost epidermal cells
thick skin
location: palms, soles, fingers and toes
thick layer
sweat glands present
thin skin
location: everywhere but hands and feet
thin layer
sweat glands, hair follicles and sebaceous glands present
life of a keratinocyte
- start from stem cels in the stratum basale
- mitosis occurs until cells migrate 2-3 cells away from the dermis
- new keratinocytes push the older ones upward until they make it to the skins surface and flake off after 30-40 days
- in stratum granulosum 3 things happen
- they die
- keratohyalin granules release filaggrin
- cells are water-proofed
- cells above water barrier die quickly and are exfoliated
dermis
connective tissue layer
-contains blood vessels, sweat glands (merocrine and apocrine), sebaceous gland, and nerve endings
-also the hair follicles and nail roots
*dermal papillae is the border between the epidermis and the dermis top
Top layer- papillary layer: areolar tissue
-rich in small blood vessels
Bottom Layer- reticular layer: dense, irregular connective tissue
hypodermis
layer underneath the skin -areolar and adipose tissue -pads the body -binds skin to the underlying tissues subQ fat: energy reservoir and thermal insulation
skin function
resistant to trauma and infection
- keratin and acid mantle
- waterproof
- barrier against UV radiation and harmful chemicals
- vitamin D systhesis
- sensation
- thermoregulation
- nonverbal communication
- transdermal absorption
Dark skin
synthesizes more melanin
melanin granules are spread out more
melanin degrades slower
melanized cells seen throughout epidermis
-darker the skin: higher levels of eumelanin
light skin
melanin clumped near keratinocyte nucleus
melanin degrades rapidly
little seen beyond stratum basale
-lighter the skin: high levels of pheomelanin
colors of diagnostic value
cyanosis-blueness of skin from oxygen deprivation
pallor-pale or ashen color when there is little blood flow through the skin
hematoma(bruise)- mass of clotted blood showing through the skin
albinism- genetic lack of melanin resulting in white hair, pale skin and pink eyes
jaundice- yellowing of skin and sclera due to excess of bilirubin in blood
erythema-abnormal redness of skin due to dilated cutaneous vessels
UV radiation
adverse effects: -skin cancer -degrades folic acid, needed for normal cell devision, fertility and fetal development desirable: -stimulates synthesis of vitamin D
structure of the hair
bulb, root, shaft, follicle(dermal papilla, hair matrix, epithelial root sheath and connective root sheath)
Bulb
swelling at base where hair originates
-living cells are only in or near this area
root
remainder of hair in follicle
shaft
portion above skin surface
hair matrix
region of mitotically active cells directly above papilla
-hairs growth center
epithelial root sheath
extension of epidermis
next to hair root
bulge: source of stem cells for follicle growth
connective tissue root sheath
from dermis
surrounds epithelial root sheath
layers of hair
medulla: core with loosely arranged cells and air space
cortex: most of hair; several layers of keratinized cells
cuticle: multiple layers of thin scaly cells overlapping
hair cycle
Anagen, catagen, telogen
anagen
growth stage
- stem cells multiply
- push dermal papilla deeper–> forms epidermal root sheath
- cells directly above dermal papilla=hair matrix
- becomes hair cells, make keratin and die as pushed up
- new hair grows up follicle, often among old club hair
catagen
degenerative stage, mitosis stops and sheath cells below bulge die
- follicle shrinks and dermal papilla moves up to bulge
- base of hair keratinizes–>hard club– club hair
- loses its anchorage
- easy to pull out by brushing
telogen
resting stage, when papilla reaches bulge
hair function
trunk and limb:vestigial
hair receptors: alert us
scalp: retain heat and protects against sunburn
pubic and axillary hair: signifies sexual maturity, aid in transmission of sexual scents
eyelashes and eyebrows: nonverbal communication
structure of the nails
very thin, dead cells and hard keratin
- nail plate
- free edge
- nail body
- nail root
- nail fold
- nail groove
- nail bed
- nail matrix
- lunule
- eponychium (cuticle)
nail plate
hard part of nail
free edge
overhangs fingertip
nail body
visible attached part
nail root
extends under skin
nail fold
surrounding skin above nail
nail groove
separates nail fold and nail plate
nail bed
skin under the nail plate
nail matrix
growth zone, thickened stratum basale
-mitosis=nail growth
lunule
opaque white cresent
eponychium
cuticle
-narrow zone of dead skin
glands
merocrine apocrine sebaceous ceruminous mammmary
Merocrine (eccrine)
function: secretes watery sweat that cools the body
open to: the skin surface
location: entire body
apocrine
function: produce thick, milky sweat with fatty acids
opens to: ducts go to hair follicles
location: groin, anal region, axilla, areola, bearded area
sebaceous glands
sebum: oily secretion made
flask shaped glands opening into hair follicle
keeps hair and skin from becoming dry, brittle and cracked
ceruminous glands
only in external ear canal
secretion+sebum+dead epithelial cells=ear wax
-keeps eardrum pliable
-waterproofs canal
-kills bacteria
-makes guard hairs sticky=blocks foreign particles
coiled tubular glands open to skin surface
mammary glands
milk producing glands develop only during pregnancy and lactation
- modified apocrine sweat gland
- richer secretion opens into nipple
sweat
begins protein-free filtrate of blood plasma
- K, urea, lactic acid, ammonia, some salt
- some drugs excreted in sweat
- 99% water with a pH of 4-6
- acid mantle: inhibit bacterial growth
skin cancer
induced by UV rays (easiest to treat, highest survival rates in caught early and most common)
- basal cell carcinoma
- squamous cell carcinoma
- malignant melanoma
burns
damage done to the skin due to UVA and UVB rays
- 1st, 2nd, 3rd degree
- leading cause of accidental death due to fluid loss, infection and toxic effects of eschar
1st degree burn
partial-thickness burn; only epidermis
-most sunburns
2nd degree burn
partial-thickness burn; epidermis and part of dermis
- blistered and painful
- leaves part of dermis intact
3rd degree burn
full thickness burn; skin and often deeper tissues destroyed
- requires skin graft
- needs fluid replacement and infection control
