the integumentary system - biology building...
TRANSCRIPT
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The Integumentary System
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The Integumentary System
Integument is skin Skin and its appendages make up the
integumentary system A fatty layer (hypodermis) lies deep to it Three distinct regionsEpidermisDermisHypodermis
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Functions of skin
Protection Cushions and insulates and is waterproof Protects from chemicals, heat, cold, bacteria Screens UV
Synthesizes vitamin D with UV Regulates body heat Prevents unnecessary water loss Sensory reception (nerve endings)
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Epidermis
Keratinized stratified squamous epithelium Four types of cellsKeratinocytes deepest, produce keratin
(tough fibrous protein)Melanocytes - make dark skin pigment
melanin Merkel cells associated with sensory
nerve endings Langerhans cells macrophage-like
dendritic cells
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Epidermis
Layers (from deep to superficial)Stratum basale or germinativum single row of
cells attached to dermis; youngest cellsStratum spinosum spinyness is artifactual;
tonofilaments (bundles of protein) resist tensionStratum granulosum layers of flattened
keratinocytes producing keratin (hair and nails made of it also)
Stratum lucidum (only on palms and soles)Stratum corneum horny layer (cells dead,
many layers thick)
(see figure on next slide)
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Epithelium: layers (on left) and cell types (on right)
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Remember
Four basic types of tissue
Epithelium epidermis just discussedConnective tissue - dermisMuscle tissueNervous tissue
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Dermis Strong, flexible connective tissue: your hide Cells: fibroblasts, macrophages, White Blood
Cells Fiber types: collagen, elastic, reticular Rich supply of nerves and vessels Critical role in temperature regulation (the
vessels) Two layers (see next slides)
Papillary areolar connective tissue; includes dermal papillae
Reticular reticulum (network) of collagen and reticular fibers
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*Dermis layers
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*Dermal papillae
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Epidermis and dermis of (a) thick skin and (b) thin skin(which one makes the difference?)
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Fingerprints, palmprints, footprints Dermal papillae lie atop dermal ridges
Made of areolar tissue Elevate the overlying epidermis into epidermal ridges Are sweat films because of sweat pores Genetically determined
Flexion creases Deep dermis, from continual folding
Fibers Collagen: strength and resilience Elastic fibers: stretch-recoil
Striae: stretch marks Tension lines (or lines of cleavage)
The direction the bundlesof fibers are directed
The dermis is the receptive site for the pigment of tattoos
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Hypodermis
Hypodermis (Gk) = below the skin Subcutaneous (Latin) = below the skin Fatty tissue which stores fat and anchors
skin (Adipose cells) Different patterns of accumulation
(male/female)
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Skin color Three skin pigmentsMelanin: the most importantCarotene: from carrots and yellow vegiesHemoglobin: the pink of light skin
Melanin in granules passes from melanocytes (same number in all races) to keratinocytes in stratum basaleDigested by lysosomesVariations in colorProtection from UV light vs vitamin D?
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Skin Accessory Structures
Derived from epidermis but extend into dermis
IncludeHair and hair folliclesSebaceous (oil) glandsSweat (sudoiferous) glandsNails
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Nails
Of hard keratin Corresponds to hooves and claws Grows from nail matrix
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Hair and hair follicles: complexDerived from epidermis and dermisEverywhere but palms, soles, nipples, parts of genitalia
*arrector pili is smooth muscle*
Hair papilla is connective tissue________________
Hair bulb: epithelial cells surrounding papilla
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Functions of hairWarmth less in man than other mammalsSense light touch of the skinProtection - scalp
PartsRoot imbedded in skinShaft projecting above skin surface
Make up of hair hard keratin Three concentric layersMedulla (core)Cortex (surrounds medulla)Cuticle (single layers, overlapping)
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Types of hair Vellus: fine, short hairs Intermediate hairs Terminal: longer, courser hair
Hair growth: averages 2 mm/week Active: growing Resting phase then shed
Hair loss Thinning age relatedMale pattern baldness
Hair color Amount of melanin for black or brown; distinct form of
melanin for redWhite: decreased melanin and air bubbles in the
medullaGenetically determined though influenced by
hormones and environment
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Sebaceous (oil) glands Entire body except palms and soles Produce sebum by holocrine secretion Oils and lubricates
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Sweat glands Entire skin surface
except nipples and part of external genitalia
Prevent overheating 500 cc to 12 l/day!
(is mostly water) Humans most
efficient (only mammals have)
Produced in response to stress as well as heat
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Types of sweat glands Eccrine or merocrine
Most numerous True sweat: 99% water, some salts, traces of wasteOpen through pores
Apocrine Axillary, anal and genital areas only Ducts open into hair follices The organic molecules in it decompose with time - odor
Modified apocrine glands Ceruminous secrete earwaxMammary secrete milk
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UV Radiation 200 nm 280nm 320nm
400nmUVC UVB UVA
(absorbed by ozone) (highly carcinogenic) (weakly carcinogenic)
Acute & Chronic effects from UV radiation
Short term itching, nausea, pruritis, xerosisLong term - polymorphous light eruption, disseminated superficial actinic porokeratosis, mid-dermal electrolysis and actinic granulomas, melanomas, basal and
squamous cell carcinomas
Pre-existing photosensitivity in Lupus Erythmatosus, Polymorphous Light Eruption, Porphyria, and Rosacea significantly exacerbated by exposure to indoor tanning
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Emergence of tanning 1930s & 40s Medical profession encouraged sun exposure
as benefit to children
1948 First reported studies of vitiligo with oral & topical psoralen
Development of tan for cosmetic purposes French designer Coco Chanel
1970s Development of UVA beds for medicinal purposes
Commercialization soon after with formation of the Indoor Tanning Association
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Skin cancers
Melanoma in U.S
Incidence rates rising by 4-8% each year Lifetime incidence is 1/71 3% of all cancers 1% of all cancer deaths Most common cause of death in women
30-39 years
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Skin Cancers - MelanomasMelanoma in the U.S
0
10000
20000
30000
40000
50000
60000
70000
2000 2001 2002 2003 2004 2005 2006
Year
New
cas
es
7000
7200
7400
7600
7800
8000
Deat
hs
New cases Melanoma Deaths
Chart1
477007700
514007800
536007400
542007600
551007910
595807770
621907910
New cases
Melanoma Deaths
Year
New cases
Deaths
Melanoma in the U.S
SEER
SEER database
IncidenceMortality
WhitesMalesFemalesTotalMalesFemalesTotal
2000273002040047700480029007700
2001290002240051400500028007800
2002301002350053600470027007400
2003299002430054200470029007600
2004299002520055100505028607910
2005335802600059580491028607770
Yearestimated new cases for all US sitesMortality
2000477007700
2001514007800
2002536007400
2003542007600
2004551007910
2005595807770
2006621907910
SEER
&A
Page &P
New cases
Melanoma Deaths
Year
New cases
Deaths
Melanoma in the U.S
Sheet2
Sheet3
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Skin cancers - Melanomas
Risk factors:
Family history Red/Blond hair Ample UV exposure (freckling on upper back, history
of 3 or more sunburns before age 20, 3 or more outdoor jobs before age 20)
Actinic keratosis Skin types I & II Advanced age Atypical or congenital nevi
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Skin typesFitzpatricks classification 1977
SED = sub erythemal dose
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Skin type assessment
Sun sensitivity or skin type remains constant during a lifetime
Self assessment by individual tanners
Assessment by low-wage, insufficiently trained tanning salon operators
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Indoor Tanning Association
Total Number of Professional Indoor Tanning Facility Businesses: 25,000
Total Number of Professional Tanning Business Employees: 160,000
Total Professional Indoor Tanning Facility Customer Base: 30 million
Total Revenues Professional Indoor Tanning Facilities: $5 billion
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Indoor Tanning IndustryMisleading advertisements &/or falsified messages:
Promoting UV protection through indoor tanning (lack of sufficient epidemiological evidence)
Promotion of health benefits through Vitamin D production
Promotion of trade-offs of certain internal cancers
Stand against sunscreens
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Indoor Tanning IndustrySignificant advertising & promotion to students
Formed a Political Action Committee (PAC) to prevent ban on under-18 tanning
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Indoor Tanning IndustryTanning salon operator education:
Through 2 private institutions National tanning Training Institute (NTTI) and International Smart Tan Network (ISTN).
No training for skin typing
No training for radiation related burns and/or emergency procedures
No demonstration of equipment handling
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Indoor Tanning
Source: www.cartoonstock.com
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Tanning Salon Operators
Source: www.cartoonstock.com
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Regulation & LegislationFDA regulates equipment, adherence to performance standards, warning signs (FDA, 21 CFR Ch.1 1040.20)
Regulation since 1979 Federal standards adopted to protect customers from eye and skin injuries
1985 Amendments by allowing longer exposure times for UVA emitting lamps
1986 Policy letter published on recommended exposure schedules
Currently no regulation or monitoring of exposure times of patrons, no requirements for maintaining much information
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Regulation & LegislationFTC prohibits deceptive advertising
Individual states governance
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Screening
Differences of opinions:
AAD, ACPM regular screeningIOM, NCI insufficient evidence for screeningUSPSTF, CTF screening at-risk population
Early detection of melanomas: High 5-year survival rate
External & visible cancer with known risk factors
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DiscussionAccording to Sharon A. Miller at the FDAs Center
for Devices and radiological Health:
FDA does not recommend the use of indoor tanning equipment
Comments:- FDA does not regulate prevalence of indoor
tanning- Currently no legislation protecting minors explicitly- No safeguards in place to protect the general
tanning population - No requirements for exposure schedules or
monitoring of UV radiation sessions in tanning salons
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Disorders of the integumentary system BurnsThreat to life
Catastrophic loss of body fluids Dehydration and fatal circulatory shock Infection
Types First degree epidermis: redness (e.g. sunburn) Second degree epidermis and upper dermis: blister Third degree - full thickness
Infections Skin cancer
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BurnsFirst-degree(epidermis only; redness)
Second-degree(epidermis and dermis,with blistering)
Third-degree(full thickness, destroying epidermis, dermis, often part of hypodermis)
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Critical burns
Over 10% of the body has third-degree burns
25 % of the body has second-degree burns
Third-degree burns on face, hands, or feet
Estimate by rule of 9s
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Tumors of the skin Benign, e.g. warts Cancer associated with UV exposure
(also skin aging)Aktinic keratosis - premalignantBasal cell - cells of stratum basaleSquamous cell - keratinocytesMelanoma melanocytes: most dangerous;
recognition: A - Asymmetry B - Border irregularity C - Colors D - Diameter larger than 6 mm
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Basal cell carcinoma
Sqaumous cell carcinoma
Melanoma
Skin Cancer
The Integumentary SystemThe Integumentary SystemFunctions of skinEpidermisEpidermisEpithelium: layers (on left) and cell types (on right)RememberDermisSlide Number 9Slide Number 10Fingerprints, palmprints, footprintsHypodermisSkin colorSkin Accessory StructuresSlide Number 15NailsHair and hair follicles: complexDerived from epidermis and dermisEverywhere but palms, soles, nipples, parts of genitalia Slide Number 18Slide Number 19Sebaceous (oil) glandsSweat glandsTypes of sweat glandsUV Radiation Emergence of tanningSkin cancersSkin Cancers - MelanomasSkin cancers - MelanomasSkin typesSkin type assessmentIndoor Tanning AssociationIndoor Tanning IndustryIndoor Tanning IndustryIndoor Tanning IndustryIndoor TanningTanning Salon OperatorsRegulation & LegislationRegulation & LegislationScreeningDiscussionDisorders of the integumentary systemBurnsCritical burnsTumors of the skinSlide Number 44