The Integumentary System

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

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)

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

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)

Epithelium: layers (on left) and cell types (on right)

Remember

Four basic types of tissue

Epithelium epidermis just discussedConnective tissue - dermisMuscle tissueNervous tissue

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

*Dermis layers

*

*

*Dermal papillae

Epidermis and dermis of (a) thick skin and (b) thin skin(which one makes the difference?)

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

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)

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?

Skin Accessory Structures

Derived from epidermis but extend into dermis

IncludeHair and hair folliclesSebaceous (oil) glandsSweat (sudoiferous) glandsNails

Nails

Of hard keratin Corresponds to hooves and claws Grows from nail matrix

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

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)

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

Sebaceous (oil) glands Entire body except palms and soles Produce sebum by holocrine secretion Oils and lubricates

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

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

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

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

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

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

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

Skin typesFitzpatricks classification 1977

SED = sub erythemal dose

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

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

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

Indoor Tanning IndustrySignificant advertising & promotion to students

Formed a Political Action Committee (PAC) to prevent ban on under-18 tanning

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

Indoor Tanning

Source: www.cartoonstock.com

Tanning Salon Operators

Source: www.cartoonstock.com

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

Regulation & LegislationFTC prohibits deceptive advertising

Individual states governance

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

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

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

BurnsFirst-degree(epidermis only; redness)

Second-degree(epidermis and dermis,with blistering)

Third-degree(full thickness, destroying epidermis, dermis, often part of hypodermis)

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

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

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