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103 Cards in this Set

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Two major regions of the skin
- epidermis
- dermis
- keratinized stratified squamous epithelium.
The epidermis is composed of
- They are the most common (90%) of the epidermal cells- produce keratin protein
– produce lamellar granules
Keratinocytes
- makes skin tough and provides protection
keratin
- release a lipid-based, water repellant, sealant
lamellar granules
- these produce the pigment melanin, which moves to the keratinocytes and absorbs damaging U.V. rays of the sun.
Melanocytes
- arise from red bone marrow and participate in the immune response against invading microbes.
Langerhans cells
- serve in the sensation of touch.
Merkel cells
Strata (layers) of the epidermis
- corneum
– lucidum
– granulosum
– spinosum
- basale
- is the deepest layer of epidermis
-contains keratinocytes and stem cells that divide to produce new keratinocytes
-hemidesmosomes bind keratinocytes to the basement membrane.
Stratum basale
-is where cells begin to become flattened.
Stratum spinosum
-in the middle and is where cells undergo apoptosis – contains keratohyalin Lamellar granules
Stratum granulosum
- cell death
Apoptosis
- is a distinctive protein the stratum granulosum, which converts intermediate filaments called tonofilaments into keratin
keratohyalin
- occurs only in thick skin and contains flattened, clear, dead, keratinocytes.
Stratum lucidum
-Is the outer most stratum and is made of 25-30 layers of dead flat keratinocytes.
Stratum corneum
On average it takes ___________ for a cell produced in the stratum basale to rise to the surface and be sloughed off.
one month
- the second, deeper layer of the skin
- mainly composed of C.T. w/ relatively few cells.
– papillary region
– reticular region
Dermis
- is more superficial and consists of areolar C.T. in projections called dermal papillae.
Papillary region
- These projections contain blood vessels that nourish the epidermis, and nervous tissue for various sensations.
dermal papillae
- consists of dense irregular C.T. w/ lots of collagen fibers that form a net.
Reticular region
-are small tears in the dermis caused by extensive stretching in pregnancy or obesity.
Striae (stretch marks)
- is the major body pigment and it varies the skin color from yellow to black.
- The number of melanocytes does not vary between the races but the amount of _______ produced does.
U.V. exposure increase enzyme activity in melanosomes which increase ______ production resulting in a suntan.
This protects skin from UV light.
Melanin
- in cells called melanocytes
– produce melanin
melanosomes
- a foreign pigment is inserted into the dermis. These can be removed with lasers but this is expensive and can be painful.
tattooing
- hair is composed of columns of keratinized, dead cells connected together by
Structure
- the part of the hair that projects from the skin.
Shaft
- the part of the hair below skin surface.
Root
- surrounds the root as an internal and external root sheath (epidermal root sheath).
Hair follicle
- an enlarged structure at the base of the hair follicle. It contains:
Bulb
- contains blood vessels that nourish hair.
Papilla of hair
- a ring of cells which divide to form new hair.
Matrix
- muscle that contracts to raise hair on skin. (Causes goose bumps)
Arrector pili
Function of hair: on the head
- protects from UV rays and from injury.
Function of hair: on the eyebrow and eyelashes
- protects eyes from debris.
Function of hair: -in nostrils and ear canal
- prevents taking in of insects and particles.
Function of hair:_______ heat loss.
decreases
- slight movement of hairs stimulates neurons called hair root plexuses surrounding the follicles.
Touch reception
- tightly packed keratinized epidermal cells and they normally grow Approx. 1 mm per week.
Nail Structure
Each nail consists of:
nail root
nail body
free edge
eponychium (cuticle)
lunula
hypochium
- the part of the nail underneath the skin.
Nail root
- the visible part up to the distal end of the finger.
Nail body
- the part of the nail that extends past the distal end of the digit.
Free edge
- the narrow band of epidermis above the proximal border of the visible nail.
Eponychium (cuticle)
- the part moon-shaped area at the base of the nail. It is white because it lies above a thick stratum basale in the nail matrix
Lunula
- where new cells are produced for nail growth.
nail matrix
- is the thickened stratum corneum below the free edge and it secures the nail to the finger tip
Hyponychium
Nail Function:
-Protect against trauma to ends of digits.
- For scratching.
- For manipulating small objects.
- are usually associated with hair and occur everywhere except for palms and soles of feet. They secrete an oily substance called sebum.
Sebaceous glands
-Keeps hair and skin from drying out.
- Keeps skin soft.
- inhibits bacterial growth.
Sebum
2 types of Sudoriferous (sweat) glands:
eccrine
aprocrine
- are more common
- occur everywhere except for lips, nail beds, genitalia, and eardrums.
- produce common sweat, which serves to regulate body temperature and eliminate a little waste.
Eccrine (ordinary sweat) glands
- occur mainly in the skin of the armpit, pubic region, areolae, and beard of males.
- During sexual excitement and emotional stress, they produce a more viscous secretion known as a “cold sweat”.
Apocrine glands
- occur in skin of auditory canal and secrete wax (cerumen) to trap foreign particles.
Ceruminous glands
Five major functions of skin
-Thermoregulation
-protection
-sense various physical stimuli
– extretion and absorption
– synthesis of vitamin D
- if the body temperature is too high, the skin releases sweat to cool the body.
- the blood vessels dilate (widen) to deliver more heat to the skin (vasodilatation).
-If the body temperature is too low, vasoconstriction works to conserve more body heat.
functions of skin:
Thermoregulation
functions of skin:
abrasion, microbes, dehydration, and UV radiation.
functions of skin: Protection
functions of skin
- some waste ions and organic molecules are released through skin. Topical drugs are absorbed through the skin because they are lipid-soluble.
functions of skin: Excretion and absorption
functions of skin:
-In skin, sunlight (UV) activates a chemical that later becomes Vitamin D (calcitriol) which aids in the absorption of calcium from food.
functions of skin: Synthesis of Vitamin D
functions of skin:
1. Basal epidermal cells begin to migrate (move) across the wounded area in sheets until they have contacted other cells on all sides. (contact inhibition)
2. Other basal cells divide to replace those that have left, to fill in.
3. Then all basal cells will divide to form new layers.
Epidermal wound healing:
1. Inflammatory phase
2. Migratory phase
3. Proliferative phase
4. Maturation phase
Deep wound healing (cut extends into the dermal tissue):
- Blood clot forms
- Vasodilatation and increased vessel permeability deliver pathogen fighting cells and wound healing cells to the wound.
Inflammatory phase
Clot becomes a scab
- Epithelial cells move (migrate) across to form a bridge
- Fibroblasts synthesize scar tissue called granulation tissue
- Damaged blood vessels grow back
Migratory phase
- growth of epithelial cells and deposition of collagen by fibroblasts and continued growth of blood vessels below the scab.
Proliferative phase
- Scab sloughs off
- Collagen fibers become organized
- Blood vessels are restored
- Fibroblasts decrease in number
Maturation phase
-develops from ectoderm tissue.
epidermis
-grows as keratinized epithelium from it‘s base. It does not reach the tip of the digit until the 9th month.
nail
-begin as down growths of stratum basale into the dermis. They produce a delicate fetal hair called lanugo.
Hair follicles
- develop as down growths of stratum basale.
Sudoriferous (sweat) glands
-develops from mesoderm tissue.
dermis
- Collagen fibers decrease in number and break.
- elastic fibers become less elastic. These changes produce wrinkles.
- Hair and nails grow more slowly.
- Pathogen fighting cells decrease in number.
- Dry and broken skin is caused by a decrease in the size of sebaceous glands.
- More susceptibility to heat strokes since sweat production is decreased.
- Pigment blotching (age spots) occur because of an increase in the size of melanocytes.
- Skin is thinner and heals more slowly.
Describe the effects of aging on the integumentary system.
Burns: Causes
- excessive heat, electricity, radioactivity, or caustic chemicals, these will destroy (denature) proteins in the skin.
Burns: Effects
- skin looses thermoregulation and protection from pathogens and desiccation. These vary by type of burn.
First- degree burn:
affects only epidermis (e.g. mild sunburn)
Second- degree burn:
destroys part of dermis (blisters)
Third degree (full-thickness) burn:
extends into subcutaneous layer.
Skin Cancer
-the primary cause is excessive sun exposure.
Basal cell carcinomas
- make up 78% of all skin cancers and rarely metastasize.
Squamous cell carcinomas
- most arise from epidermis in preexisting skin lesions on sun-exposed skin. Have a variable tendency to metastasize
Watch for the ABCD’s of cancer
-Asymmetry
-Border irregular
-Color is uneven
-Diameter is greater than an eraser on a pencil
- caused by a constant cut-off of blood supply because of bone pressing against an object. (E.g. bed) Can produce ulceration of tissue, skin breaks, and become infected.
Pressure ulcers (bedsores, decubitus ulcers)
an area where skin has been scraped away
abrasion
a superficial fungal infection of the skin of the foot
athlete's foot
a collections of serous fluid within the epidermis or between the epidermis and dermis, due to short term but severe friction
blister
refers to a large blister
bulla
an area of hardened and thickened skin that is usually seen in palms and sole and is due to persistant pressure and friction
callus
a lesion, usually in oral mucoius membrane caused by the Type 1 herpes simples virus (hsv) transmitted by oral or respiratory routes. The virus remains dormant until triggered by factors such as ultraviolet light, hormonal changes, and emotional stress
cold sore
also called a fever blister
a collectoin of sebaceous material and dead cells in the hair follicle and excretary duct of the secaceous gland. Usually found over the face, chest, and back
comedo also known as a blackhead
inflammation of the skin characterized by redness, itching, and swelling and caused by exposure of the skin to chemicals that bring about an allergic reacton, such as poison ivy toxins
contact dermatitis
a painful conical thickening of the stratum corneum of the epidermis found principally over over toe joints and between the toes, often caused by friction or pressure.
Corn
a sac with a distinct connective tissue wall, containing a fluid or other material
cyst
an inflammation of the skin characterized by patches of red, blistering, dry, extremely itchy skin. It occusrs mostly in skin creased in the wrist, backs of knees, and fronst of the elbows. It typically begins in infancy and many children outgrow the condition
eczema
local destruction of skin and subcutaneous tissue on exposed surfaces as a result of extreme cold.
In mild cases, the skin is wollen and there slight pain.
In severe cases there is considerable swelling, some bleeding, no pain, and blistering.
If left untreated gangrene may develop.
Treated by rapid rewarming
frostbite
localized tumor of the skin and subcutaneous layer that results from an abnormal increase in blood vessels.
hemangioma
One type of hemangioma that is present at birth
- flat, pink, red, or purple lesion
- usually at the nape of the neck
portwine stain
reddened elevated patches of skin that are often itchy.
Most commenly caused by infections, physical trauma, medications, emotional stress, food additived, and certian food allergies
Hives - also called urticaria
formation of hardened growth of epidermal tissue
keratosis
premalignant lesion of the sun-exposed skin of the face and hands
solar keratosis
an irregular tear of the skin
laceration
a small, round skin elevaton less than 1 cm in diameter. ex: pimple
papule
itching, on of the most common dermatoligical disorders.
it may be caused by skin disorders (infections), systemic disorders (cancer, kidney failure) psycogenic factors (stress) or allergic reactions
puritis
in reference to a medication - applied to the skin surface rather than injested or injected
topical
mass produced by uncontrolled growth of epithelial skin cells caused by a papillomavirus.
most are noncancerous
wart