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74 Cards in this Set
- Front
- Back
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what is skin |
a large organ composed of all 4 tissue types |
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integumentary functions |
1. protection 2. Excretion 3. Maintenance of body temperature 4. Syntheis of Vitamiun D |
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protection |
fluid loss, mechanical & or chemical damage |
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excretion |
excretion of water, salts & organic wastes |
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maintenance of body temperature |
insulates heat loss & cools down with sweat |
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synthesis of vit D |
UV rays induce synthesis of cholecaliferol (precursor to Calcitirol) |
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storage of lipids |
in dermal layer & hypodermmis |
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detect enviroment change |
recpetors for touch, presue, pain & temperature |
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2 major layers of skin |
epidermis & dermis |
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epidermis |
epidermis is only epithelial tissue inly |
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dernus |
dermis is layer of connective tissue, nerse & muscle |
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Subcutaneous tissue (subQ or hypoderm) |
layer of adispose & aerolar tissue |
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subQ |
subcutaneous injection |
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(4) overview of Epidermis |
Stratified sqamous epithelium contain no blood vessels 4 types of cell 5 distinct strata (layers in thich skin & 4 distinct strata in thin skin |
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4 cell types of epidermis |
kerattinoctyles melancotyes lanhern cells Merkel cells |
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Kerantinocytes |
90% produces keratin |
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melanocytes |
8% produces melanin pigment melanin transferredto other cekks with longer cell processes |
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Langerhan cells |
from bone marrow provide immunity q |
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merkel cells |
in deepest layer from touch receptor with sensory neuron |
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Layers (Strata) of the Epidermis |
Stratum corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale (or Geminativum |
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Stratum Germinativum (Basale) |
Deepest single layer of cells
Combination of merkel cells, melanocytes, keratinocytes & stem cells that divide repeatedly
Cells attached to each other & to basement memebrane by desmosomes & demidesmosomes, respectively
Intermediate (tonofilaments) filaments strengthen cell & attachments |
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Stratum Spinosum |
8-10 cell layers held together by desmosomes
During slide preperation, cell shrink and look spiny
Melanosomes (containing melanin) is taken in from nearby melanocytes
melanin protects nucleus from UV rays |
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Stratum Granulosum |
3-5 layer of flat dying vells
show nuclear degeneration
contain dark-staining keratohyalin granules that release lipid that repels water
Melanosomes reach this layer in dark skin people |
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Stratum Lucidum |
Seen in thick skin on palms & soles of feet
3-5 layers of clear, flay, dead cells
Contains precursor of kertatine ( keratohyalin converst tonofilament into keratin) |
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Stratum Corneum |
25-30 layers of flay dead cells filled with keratin and surrounded by lipids
continuously shed
Barried to light, heatm waterm chemicals & bacteria
Fiction stimulaes cell formation |
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Keratinization & Epidermal Growth |
stem cells divide to produce keratinocytes
As keratinocytes are pushed up towards the surface they fill with keratin
Cornification is process of keratinization occuring on all body surfaces (except eye ball)
4 week journey unless outer layers removed in abrasion or Psoriasis in which cell reach the surface in 10 days
Cell Last on the surface about 2 weels until slughed off
Homrone EGF (epidermal growth factor) can speed up process by increasing mitosis
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Insensible perspiration |
is not felt, it is responsibile for removing about 1 pt of water/day through osmosis |
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Sensible Perspiration- |
through active sweat glands to cool the body by evaporation |
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Dermis |
connective tissue layer composed of collagen & elastic fibers. fibroblasts, macrophages & fat cells
contains hair follicles, glands, nerves & blood vessel
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major regions of dermis |
papillary region
reticular region |
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papillary plexus |
role in decubitus bed sores & transdermal patches |
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papillary region |
top 20% of dermis
composed of loose CT & elastic fibers
finger like projections called dermal papillae
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functions of Papillary Region |
anchors epidermis to dermis
contains capillaries that feed epidermis
contains Meissner's corpuscles (touch) & free nerve endings (pain & temperature) |
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Epidermal ridges |
formed in fetus as epidermus confroms to dermal papillae
Fingerprints are left by sweat glands open on ridges increase grip of hand
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Reticular Regions |
Dense irregular connective tissue
contains interlacing collagen and elastic fibers
Packws with oil glands, sweat gland ducts, fat & hair follicles
provides stength, extensibility & elasticity to skin stretch marks are dermal tears from exteme stretching which overcomes the elastic barrier of elastic fibers
Lines of Cleavage- direction of fibers
Blood & Lymph coming up from subcutaneous |
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Melanin produced in epidermis by____ |
melanin produced in epidermis by melanoctyes
same number of melanocytes in everyone, but differing amounts of pigment produced
results vary from yellow to tan to black color
melanocytes convert tyrosine to melanin UV in sunlight increases melanin production |
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freckles or liver spots= |
melanicyes in a patch
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albinism= |
inherited lack of tyrosinase; no pigmet |
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vitiligo |
may be autoimmune loss of melanocytes in areas of the skin which then produces white patches |
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carotene in dermis |
yellow-organe pigment (precursor of vitamin A) found in stratum corneum & fatty areas of dermis |
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Hemoglobin |
red, oxygen-carrying pigment in blood cells
if other pigments are not present, epidermis is translucent so pinkness wil be evident |
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Jaundice |
yellowish color to skin and whies of eyes
buildup of yellow bilirubin in blood from liver diseasw
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Cyantoic |
bluish color to nail beds and skin
hemoglobin depleted of oxygen looks purple-blue |
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Erythema |
redness of skin due to enlargement of capillaries in dermis
dring inflammation, infection, allergy or burns |
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Pallor |
paleness due to anemia or shock |
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Subcutanous (Hypodermis) Layer |
Blood Resevoir Subcutanous fat as an every source stores Carotene pigment as precursor to Vitamin A |
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cells sink inward during development to form |
hair oil glands sweat glands nails |
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shaft |
visible: internal organizatoin is complete is complete
medulla, cortex, & cuticle |
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Root |
belows the surface |
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follicle surrounds ___ |
follicle surrounds root
external root sheath
internal root sheath
base of follicle is bulb
blood vessels germinal cell layer |
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hair matrix is |
hair matirx is portion of hair bulb for growth |
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Medulla |
incomplete layer of cells wit soft keratin |
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Cortex |
cells with stiff keratin |
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Hair Cuticle |
this single layer of heavily kerantinized cells |
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Arrector pili |
smooth muscle in dermis contracts with cold or fear
forms goodebumps as hair is pulled vertically |
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hair root plexus |
detect hair movment |
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Growth cycle= |
growth stage & resting stage |
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growth stage |
lasts for 2-5(or6) years
matrix cells at base of hair root producing length
terminal hair (thich vs course) vs Vellus (fine) |
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Resting stage (club hair) |
lasts for 3 month
matrix cells inative & follicle atrophies |
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Old hair _____ as growth stage begins again |
old hair falls out as growth stage begins again
normal hair loss is 50-100 hairs per day |
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Hair color is a result of |
hair color is result of melanin produces in melanocytes in hair bulb |
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____ contains true melanin with iron and sulfur added |
Dark hair contains true melanin |
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blonde & red hair contain_____ with ___ and ____ added |
Blond and red hair contain melanin with iron and sulfur added |
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____ is a result of decline in melanin production |
Graying hair is result of decline in melanin production |
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white hair has ___ |
white hair has air bubbles in the medullary shaft
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functions of hair |
prevent heat loss Decreases sunburn Eyelashes help protcted eyes Touch receptors (hair root plexus) sense light touch Prevents invasion of debris or insects into nose, eyes & ears |
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Glands of the Skin |
Specialized exocrine glands found in dermis
Sebaceous (oil) glands Sudiferous (sweat) glands Ceruminous (wax) glands Mammary (milk) glands |
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Sebaceous glands |
oil glands
secretory potion in the dermis (holocrine)
most open onto hair shafts- keeps hair from drying out |
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Sebum |
combination of cholesterol, proteins, fats& salts
keeps hair and skin soft & pliable
inhibits growth of bacteria & fungi (ringworm) |
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acne |
bacterial inflammation of glands sevretions by horemones at puberty
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Vernix Caseosa |
Seum & epithelium cells coat newborn skin |
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Eccrine or Merocrin (sweat) glands |
most areas of skin
secretory portion in dermis with duct to surface
regulate body temperature with perspiration
Dilute surface & antibiotic properties |
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Aporcrine (sweat) glands |
in part they are also merocrine secretions
armpit and public region
secretion paortion od dermis with duct that opens onto hair follicle
secretions more viscous & odiferous 9due to bacterial decomposition)
Release w/ sexual arousal or stress |
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ceruminous glands |
modified sweat glands produce waxy secretioh in ear canal when mixed w/ secretions from sebaceous glands
cerumin contains secretions of oil and eax glands
helps from barried for entrance of foreign bodies
impacted cerumen may reduce hearing |
