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Kayla Lay P2 Integumentary System - Coggle Diagram
Kayla Lay P2 Integumentary System
Major functions of the skin
Cutaneous sensations
Exteroreceptors: respond to stimuli outside body (temp, touch)
Free nerve endings: sense painful stimuli
Metabolic functions
Chemicals from keratinocytes can disarm carcinogens
Keratinocytes activate hormones
Synthesize vitamin D (calcium absorbstion)
Skin makes collagenase
Body temperature regulation
Hot temp: dilation of dermal vessels increase sweat gland activity
Cole temp: dermal blood vessels constrict
Normal temp: sweat glands produce unnoticeable sweat
Blood reservoir
Skin hold up to 5% of body's total blood volume
Skin vessels constrict to shunt blood to other organs
Protection
Biological barriers:
phagocytic cells- engulf foreign antigens; activate immune system
macrophages- present foreign antigens to white blood cells; activate immune system
DNA absorb harmful UV radiation and convert to harmless heat
Physical barrier: flat, dead keratinized cells of stratum corneum block most water and most water-soluble substances
Chemical barrier:
acid mantle- prevent bacterial multiplication from low pH
melanin- barrier against UV radiation damage
secretes- sweat (antimicrobial proteins), sebum and defensins (lubricate against friction and kill bacteria), and antimicrobial defensin
Excretion of wastes
Skin secrete nitrogenous wastes: ammonia, urea, and uric acid
Sweat cause salt and water loss
Skin cancer and ABCD rule
Squamous cell carcinoma
Keratinocytes of stratum spinosum
Scaly reddened papule on scalp, ears, lower lip, or hands
Second most common; can metastasize
Good prognosis from radiation therapy or surgical removal
Melanoma
Cancer of melanocytes; most dangerous because highly metastasize and chemotherapy resistant
Treated by wide surgical excision accompanied by immunotherapy
ABCD rule: early detection for survival
A- asymmetry (two pigmented areas do not match)
B- border irregularity (indentations)
C- several colors (black, brown, tan, sometimes red or blue)
D- larger than 6mm (diameter)
Basal cell carcinoma
Stratum basale cells proliferate; slowly invade dermis and hypodermis
Cured by surgical excision
Least malignant and most common
Degrees of Burns and Rule of Nines
Second degree
Epidermal and upper dermal damage
Blisters appear
Third degree
Skin color turns gray-white, cherry red, or blackened
No edema seen and not painful bc nerve endings destroyed
Entire thickness of skin
Skin grafting usually necessary
First degree
Epidermal damage
Localized redness, edema, and pain
Rule of Nines: volume of fluid loss
Front head- 4.5%
Back head- 4.5%
Back- 18%
Torso 18%
Back left arm- 4.5%
Front left arm- 4.5%
Front right arm- 4.5%
Back right arm- 4.5%
Back left leg- 9%
Front right leg- 9%
Front left leg- 9%
Back right leg- 9%
Genital- 1%
Layers of the skin
Dermis: underlies epithelial; mostly fibrous connective tissue
Papillary Layer
loose, interlacing collagen and elastic fibers, blood vessels
Dermal papillae- sends fingerlike projections up into epidermis
in thick skin, dermal papillae lie on top of dermal ridges (friction ridges- grip ability, sense of touch, fingerprint pattern)
Reticular layer
80% dermal thickness
coarse, dense fibrous connective tissue
elastic fibers provide stretch-recoil properties
collagen fibers provide strength and resiliency (bind water, keep skin hydrated)
Hypodermis: subcutaneous layer deep; mostly adipose tissue (absorb shock and insulates); anchor skin to underlying structures (mostly muscles)
Epidermis:superficial region; consists of epithelial tissues (keratinized stratified squamous)
Cell types
Melanocytes- spider shaped; produce pigment melanin; protect nucleus from UV damage
Dendritic cells- star shaped macrophages; key activator to immune system
Keratinocytes- produce fibrous keratin; major cells
Tactile cells- sensory receptors that sense touch
layers of skin
Stratum spinosum
several cell layers thick
keratinocytes appear spikey (prickle cells)
Stratum lucidum
only in thick skin
thin, translucent band of 2-3 rows of clear, flat, dead keratinocytes
Stratum basale
deepest epidermal layer; firmly attached to dermis; 10-25% melanocytes
single of row of cells that actively divide; cells die as it moves toward surface
Stratum corneum
three quarters of epidermal thickness
dead cells function
protect deep cells from environment
prevent water loss
protect from abrasion and penetration
barrier against biological, chemical, physical assaults
20-30 rows of flat, anucleated, keratinized dead cells
Stratum granulosum
four to six cells thick; but flattened cells, so thin layer
cell appearance changes: keratinization begins; slows water loss
cells above this layer die
Accessory Organs
Nail: hard keratin
Nail plate- protect living nail bed underneath
Root- produces most the volume of nail and nail bed
Free edge- extended part of nail plate beyond hyponychium
Nail bed- epidermis underneath keratinized nail plate
Nail matrix- thickened portion of bed responsible for growth
Nail folds- skin folds overlap border of nail
Eponychium- nail fold projects onto surface of nail body; pink
Lunule- thickened nail matrix; white
Glands
Apocrine sweat gland
confined to axillary and anogenital glands
secretion- viscous milky or yellowish sweat; contains fatty substances and proteins
larger than eccrine glands with ducts emptying into hair follicles
begin functioning at puberty; sexual scent gland (body odor)
modified apocrine galnds
ceruminous glands- lining of external ear canal; secrete cerumen
mammary glands- secrete milk
Sebaceous oil glands
most develop from hair follicles and secrete into hair follicles
relatively inactive until puberty (stimulated by hormones, especially androgens)
widely distributed, except for thick skin of palms and soles
secrete- sebum
bactericidal properties
softens hair and skin
oily holocrine secretion
Eccrine sweat gland
ducts connect to pores
function in thermoregulation (regulated by sympathetic nervous system)
most numerous; abundant on palms, soles, and forehead
secretion- sweat (water, salts, vitamin C, antibodies, dermcidin, metabolic wastes)
Hair: dead keratinized cells; hard keratin
Shaft: above scalp; complete keratinization
Cortex- several layers of flattened cells surrounding medulla
Medulla- central core of large cells and air spaces
Cuticle- outer layer of overlapping layers of single cells
Root: within scalp; incomplete keratinization
Hair follicule
Epithelial root sheath- wall of follicle
Hair matrix- actively dividing area of bulb that produces hair cells
Hair follicle receptor- sensory nerve endings; wrap around bulb
Arrector pili- small band of smooth muscle attached to follicle
Hair papilla- dermal tissue containing a knot of capillaries that supplies nutrients
Hair bulb- expanded area at deep end of follicule