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85 Cards in this Set

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  • Back
Integumentary System
consists of skin & its derivatives (sweat & oil glands, nails, hair) makeup a complex set of organs that serve several functions, mostly protective.
3 major regions of Skin
epidermis (outermost), dermis (middle), hypodermis (deepest/ adipose)
outermost region. It is a keartinized stratified squamous epithelium. Consists of 4 distinct cell types and 4 or 5 distinct layers. Functions as protection against bacteria and injury.
Cells of Epidermis
squamous keratinocytes , Melanocytes, Langerhans' (epidermal dendritic cells), occasional merkel cells
produce keratin the fibrous protein that helps give the epidermis its protective properties (kera = horn in Greek). They arise from deepest part of epidermis from stratum basale. In Stratum basale they undergo almost constant mitosis they are pushed up by new cells. When they get to the top they are dead, scale like structures. Millions rub off everyday
produce the brown pigment melanin. Spider-shaped cells found in the deepest layer of epidermis (10-25% of stratum basale cells)
Langerhans' cells
cells that help activate the immune system. Star shaped cells arise from bone marrow and migrate to the epidermis. Also called "epidermal dendritic cells"
Merkel cells
touch receptors associate w/ sensor nerve endings. Present at epidermal-dermal junction. Shaped like a spiky hemisphere each one is associated w/ a dislike sensory nerve ending. This combo is a Merkel disc.
Thick skin
covers palms, fingertips, and soles of feet. Consists of five layers (strata) from deep to superficial
5 layers of skin
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum
thin skin
all layers except stratum lucidium & other layers are thinner
stratum basale
"stratum germinativium" the deepest epidermal layer, attached to the underlying dermis along a wavy borderline that looks like corrugated cardboard. Mostly single layer of keratinocytes (youngest). Undergoing rapid mitosis. 10-25% of the cells are melanocytes & their branching processes extend among the surrounding cells and reach well into the more superficial stratum spinosum layer.
stratum spinosum
"prickly layer" several layers of live keratinocytes. Scattered among the keratinocyes are melanin granules & Langerhans' cells, wh/ are most abundant in this layer.
stratum granulosum
"granular layer" thin layer consists of 3-5 cell layers of live keratinocytes (this is the last live layer of keratinocytes). Here they change shape and flatten and accumulate keartohyaline granules and lamellated granules. Keratohyaline granules help to form keratin in the upper layers. The lamellated granules contain a waterproofing gycolipid.
stratum lucidum
"clear layer" appears as a thin transparent band. Consists of a few rows of flat, dead keartinocytes. Present only in thick skin (soles of feet, palms)
stratum corneum
"horny layer" outermost layer is a broad zone 20 to 30 cell layers thick of dead keratinized cells. Accounts for 3/4 of the epidermal thickness. Keratin & thickened plasma membranes of cells protect the skin against abrasion and penetration. Also, glycolipid between its cells waterproofs. Durable "overcoat for the body, protecting deeper cells from external environment (air), water loss, and rendering body relatively insensitive to biological, chemical, & physical assault.
2nd major skin region: Composed of strong, flexible connective tissue.
Dermis cell types
Typical of cells found in any connective tissue proper: fibroblasts, macrophages, & occasional mast cells & white blood cells.
Dermis Layers & contains?
Richly supplied w/ blood and lymphatic vessels and nerve fibers. 2 Layers: papillary & reticular.
superficial papillary layer
vasuclar, areolar connective tissue. Contains peg like projections called dermal papillae that indent the epidermis. Dermal papillaie contain capillary loops, Meissners' corpuscles (touch receptors), & free nerve endings (pain receptors). Includes the makings of the markers called fingerprints.
What makes fingerprints?
In palms and soles of feet these dermal papillaie lie atop larger mounds called dermal ridges, wh/ cause the overlying epidermis to form epidermal ridges (wh/ increases friction and enhances grip ability). Combine this w/ the sweat from pores open along their crests on the fingertips is why we leave these individual marks.
reticular layer
Accounts for 80% of the dermis thickness. It is dense irregular connective tissue. Its extracellular matrix contains thick bundles of interlacing collagen fibers called cleavage, or tension lines. Also contains flexure lines.
cleavage, or tension lines
Its extracellular matrix of dermis: reticular layer contains thick bundles of interlacing collagen fibers that run in various planes (most run parallel to skin surface). Separations (or less dense regions) between bundles form _____, or _____ lines. Surgeons cut along these lines when possible wh/ leads the skin to heal better than when cut across them.
flexure lines
Dermal reticular layer folds that occur at or near joints, where the dermis is tightly secured to deeper structures (deep creases of your palms). Since the skin cannot slide easily to accommodate joint movement in such regions, the dermis folds and deep skin creases form. Also visible on the wrists, fingers, soles, and toes.
Subcutaneous layer deep to the skin. Composed of adipose & areolar connective tissue. It acts as a shock absorber & insulator.
Skin Color Pigments
melanin, hemoglobin, & carotene
the only one made in the skin. A polymer made of tyrosine amino acids, ranges in color from yellow to reddish-brown to black.
Melanin & the Sun
Increased exposure to UV (DNA damage) leads to increased melanin production (skin gets tanner but is not more protected because damage is done). melanin protects by absorbing UV light & dissipating its heat. However, excessive sun damage can have other effects: clumping of elastin (leathery skin). Affecting the DNA leads to skin cancer.
Yellow to orange pigment found in certain plant products such as carrots. Most obvious in palms and soles of feet.
Reddish pigment responsible for the pinkish hue of skin. Pinkish hue of fair skin reflects the crimson color of oxygenated hemoglobin in the red blood cells circulating through the dermal capillaries.
Appendages of the Skin
Sweat Glands, Sebaceous Glands (oil), Nails, Hair
Sweat (Sudoriferous) Glands
different types prevent overheating of the body. Sweat is 99% water, has antibodies, salt, microbicides & metabolic waste. 2 types.
Types of Sweat Glands
Eccrine (merocrine)& Apocrine
secrete sweat, prevents overheating. More numerous than apocrine. Found in abundance on the palms, feet, & forehead.
Apocrine sweat glands
Largely confined to the axillary and anogenital areas
Ceruminous glands
located in the ear canal, secrete cerumen (ear wax), block entry of foreign material.
Mammary glands
secrete milk
Sebaceous (oil) glands
Simple alveolar (one duct) glands that are found all over the body except on the palms and soles. Secrete sebum wh/ acts as lubrication and bactericide. They function as holocrine glands. Secretion is stimulated by hormones. (relatively inactive until puberty)
Homeostatic imbalance in Sebaceous glands
results in pimples (usually caused by bacteria)
A scalelike modification of the epidermis that contain hard keratin. Nail matrix is responsible for nail growth.
Hair or Pili
Flexible Strands of dead keartinized cells produced by hair follicles
How is hair pigmented
By melanocytes at the base of the hair.
Melanocytes at base of hair
maintain warmth, alerting the body to the presence of insects on the skin, guarding the scalp.
Main regions of hair
shaft & root
Hairs 3 Layers
3 layers of keratinized cells: medulla, cortex and the cuticle
Structure of Hair follicle
root, bulb, sheath (inner & outer), hair follicle receptor, and pili muscle
Hair follicle
extend from the epidermis into the dermis and occasionally into the hypodermis.
hair bulb
deep end of the follicle located about 1/6" below the skin surface
hair follicle receptor or root hair plexus
a knot of nerve endings surrounding the hair bulb
wall of hair follicle
composed of an outer connective tissue root sheath derived from the dermis, a thickened basement membrane called the glassy membrane, and an inner epithelial root sheath.
arrector pili muscle
associated w/ each hair follicle is this bundle of smooth muscle cells called an ________. Smooth muscle, makes hair stand up straight "hair stands on end"
Types of Hair Growth
Classified as vellus or terminal
body hair of children and adult females, pale and fine
course, long hair of eyebrows, scalp, axillary & pubic regions
Hair growth & density factors
nutrition & hormones
Hair thinning
alopecia-in both sexes
true baldness
genetically determined & sex influenced condition. Male pattern baldness caused by follicular response to a metabolite of testosterone (shortening hair growth)
Integumenatary System Functions
Protection, Regulate Temp, Cutaneous Sensation, Metabolic, Blood Reservoir, Limited Excretion
Chemical & Physical & biological
Chemical Protection Function
Barriers include skin secretions and melanin
Barriers are provided by the continuity of the skin, and the harness of the keratinized cells
Barriers include the Langerhans' cells, the macrophages, and the DNA itself
Regulation of Temp
Skin reg. body temp by using the sweat glands of the skin to cool the body.
Cutaneous Sensation
made possible by the placement of cutaneous sensory receptors, wh/ are part of the nervous system, in the layers of the skin.
Metabolic function
skin makes vitamin D when exposed to sunlight
Blood reservoir
by holding up to 5% of the body's blood supply wh/ may be diverted to other areas of the body should the need arise.
Limited excretion
Limited amounts of nitrogenous wastes are excreted through the skin.
Homeostatic Imbalances of Skin
Aging, Skin Cancer, Burns, Tissue Trauma & Repair
decreasing regeneration, skin thins & less lubrication, more bruises & injury, decreasing elasticity leads to wrinkles, decreasing # of active hair follicles, decreasing melanocytes & immune cells enhances chances of getting skin cancer
Skin Cancer
Basal Cell Carcinoma, Squamous cell carcinoma, Melanoma
basal cell carcinoma
least malignant & most common. Stratum basale cells proliferate & invade the dermis & hypodermis. Slow growing & does not often metastasize. Can be cured by surgical excism in 99% of cases.
Squamous Cell Carcinoma
Arises from keartinocytes of stratum spinosum. Grows rapidly & metastasizes if not removed. Prognosis good if treated by radiation therapy or removed surgically.
Cancer of melanocytes is the most dangerous type of skin cancer because: Highly metastatitic, Resistant to chemotherapy. Chance of survival is poor if the lesion is over 4mm thick. Treated by wide surgical excision accompanied by immunotherapy.
ABCDE rules for recognizing melanoma
A-Asymmetry: The 2 sides of the pigmented spot or mole do not match. B-Border irregularity: the borders of the lesion exhibit indentations. C- Color: The pigmented spot contains several colors (blacks, browns, tans, & sometimes blues & reds). D-Diameter: The spot is larger than 6mm in diameter (the size of a pencil eraser). E-Elevation: Above the skin surface rule.
Classified according to severity: 1st, 2nd, 3rd.
1st degree burn
damage only to the epidermis
2nd degree
injure the epidermis and the upper region of the dermis. Blisters appear.
3rd degree
full thickness burns. Since nerve endings have been destroyed the burn area is not painful. Appears gray white, cherry red, or black
Rule of Nines
Estimates severity of burns. Burns considered critical if any of the following exists: over 25% of the body has 2nd degree burns. And/or over 10% of the body has 3rd degree burns. And or there are 3rd degree buns on face, hands, feet.
Tissue Trauma & repair
Body has many techniques for protecting itself from "uninvited guests" or injury. When tissue injury occurs these barriers are penetrated, this stimulates the body's inflammatory & immune responses, wh/ wage their battles largely in the connective tissues of the body.
Inflammatory chemicals released by injured cells and immune cells cause dilation of blood vessels. Redness, heat, swelling, & pain results. Clotting proteins construct a clot. Macrophage phagocytosize destroyed tissue.
Restores blood supply
Regeneration & fibrosis
Reg- Replacement of destroyed tissue. Fibrosis -proliferation of connective tissue. Fibrouse tissue begins to resemble the adjacent tissue. Surface Epithelium regenerates and the scab detaches. Results in a fully regenerated epithelium w/ underlying scar tissue.