Chapter 6: Integumentary System Flashcards
Skin
composed of different tissues Functions: 1. maintains homeostatis 2. protective covering 3. retards water loss 4. regulates body temperature 5. houses sensory receptors 6. contains immune system cells 7. synthesizes vitamin D 8. excretes small amounts of waste
Layers of Skin
Epidermis, Dermis, and Subcutaneous layer
Epidermis
outer layer composed of stratified squamous epithelium
Dermis
inner layer composed of CT, MT, NT, and blood
Subcutaneous Layer
beneath the dermis, adipose tissue of this layer insulates the body and contains blood vessels that supply the skin.
Epidermis
lacks blood vessels
keratinized: hardens the epidermis
thickest on palms and soles (0.8-1.4mm)
melanocytes provide melanin (color of skin)
rests on basement membrane - separates epidermis from dermis
Layers of Epidermis
- Stratum Corneum
- Stratum Lucidum (found on thicken skin of palms and soles)
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
(CLGSB)
The production of epidermal cells balances with loss of dead cells from stratum corneum
Keloid scars: extra epidermal cells produced
Calluses
thickening of stratum corneum
Melanocytes
lie in stratum basale and underlying CT of dermis
Melanin provides skin color and absorbs UV radiation
Dermis
boundary is uneven due to dermal papillae - ridges (fingerprints)
binds epidermis to underlying tissues
composed largely of irregular dense connective tissue (including collagenous and elastic fibers to give toughness and elasticity)
also contains muscle fibers:
smooth muscles - skin enclosing testes, hair follicles, and glands
skeletal muscles - facial muscles anchored to the skin of the face
also contains nerve cell processes to carry impulses to dermal muscles and glands and provide sensation
A tattoo is made with very fine needles injecting inks into the dermis
since dermal cells are not shed, the color is permanent
to remove it, a laser has to be used to shatter the ink molecules and the immune system removes the resulting debris
Dermal Receptors
Pacinian & Meissner’s Corpuscles
Pacinian Corpuscles
stimulated by heavy pressure
Meissner’s Corpuscles
sense light touch
Free nerve endings
respond to temperature change or factors that can damage tissue.
Hair Follicles
hair is everywhere except: palms, soles, lips, nipples & parts of the external reproductive organs (some places very fine)
Hair Follicle
is a group of epidermal cells at the base of dermis
tube-like depression that extends from surface of skin to dermis
Hair Root
embedded in the skin
Hair Shaft
extends from the surface of the skin
Hair Papilla
projection of CT that contains blood vessels
Hair
a hair is made of dead epidermal cells
a healthy person loses from 20-100 hairs/day
a typical hair will grow for 2-6 years, rest for 2-3 months, then fall out
baldness results when hair falls out and isn’t replaced
Hair color
determined by melanin
dark - more melanin; light - less melanin
cells that make melanin are called melanocytes
albino - no melanin
red- has iron pigment called trichosiderin
gray - mix of pigmented and unpigmented cells
Arrector Pilli
smooth muscle that attaches to the hair follicle.
goosebumps - contraction, function is to keep you warm.
Nails
protective coverings
Nail plate
overlies bed
Nail bed
overlies skin
Lunula
half-moon most active growing region
Nail appearance mirrors health
bluish = circulation problem
white or oval depressions = anemia
pigmented spot = melanoma
horizontal furrows = serious illness or malnutrition
curved nails = heart, lung, or liver disorders
red streaks = rheumatoid arthritis, ulcers, or hypertension
Sebaceous Glands
usually associated with hair follicles
holocrine glands - secrete:
- sebum: mix of fatty material and cellular debris
- helps keep hair and skin soft, pliable, and waterproof
- absent on palms and soles & external reproductive organs
Sweat Glands
also are called sudoriferous glands
widespread in skin
deeper dermis or hypodermis
Eccrine Glands
common on forehead, neck and back
Apocrine Glands
become active in puberty
common in axillary (armpit) regions, groin, and around nipples
Ceruminous Glands
external ear canal, secrete ear wax
Mammary Glands
secrete milk (only active with pregnancy hormones)
Hyperthermia
abnormally high body temperature
Hypothermia
abnormally low body temperature, used during some surgical procedures involving the heart, brain, or spinal cord.
they do this so the metabolic rate lowers so less oxygen is required
they will pack the patient in ice or remove blood, cool it, and return it. (usually between 78-89 degrees)
Genetic Factors
varying amounts of melanin
varying size of melanin granules
albinos lack melanin
Environmental Factors
sunlight
UV light from sunlamps
X rays
tans fade as pigmented epidermal cells become keratinized and wear away.
Physiological Factors
dilation of dermal blood vessels: pink or red (embarrassment/increased heart rate)
constriction of dermal blood vessels: pale (right before pass out)
carotene: accumulated in adipose tissue and casts yellow
jaundice: liver malfunction
Healing of Cuts
inflammation: normal response to injury or stress
- blood vessels dilate and become more permeable (allow things in)
- skin becomes red, swollen, warm, and painful to touch
- dilated blood vessels provide more nutrients and oxgen
Shallow Cut
epithelial cells divide more rapidly to fill in gap left from the cut
Dermis or subcutaneous level cut
blood vessels break and blood forms a clot/scab
Cuts
- fibroblats migrated to area and form new collagenous fibers that bind wounds together
- CT matrix release growth factors that stimulate cells to divide and regenerate damaged tissue
- phagocytic cells remove dead cells and other debris
- damaged tissues are replaced and scab sloughs off
- scar: CT is replacing skin that was damaged
First Degree Burn
superficial partial-thickness
Second Degree Burn
deep partial-thickness
burn destroys some epidermis as well as dermis
Third Degree Burn
full-thickness
- autograft: same person
- homograft: person to person
- various skin substitutes are used to cover extensive burns.
