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8/10/2019 Sistem Integumen FREE

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The Integumentary System


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The Integumentary System

Integument is skinSkin and its appendages make up theintegumentary system

A fatty layer (hypodermis) lies deep to itTwo distinct regions

EpidermisDermis


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Functions of skin

ProtectionCushions and insulates and is waterproof

Protects from chemicals, heat, cold, bacteriaScreens UV

Synthesizes vitamin D with UVRegulates body heatPrevents unnecessary water lossSensory 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 melaninMerkel cells associated with sensory nerve endingsLangerhans cells macrophage-like dendritic cells

Layers (from deep to superficial)Stratum basale or germinativum single row of cells attached todermis; youngest cellsStratum spinosum spinyness is artifactual; tonofilaments(bundles of protein) resist tensionStratum granulosum layers of flattened keratinocytes producingkeratin (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 tissue

Nervous tissue


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Dermis

Strong, flexible connective tissue: your hide Cells: fibroblasts, macrophages, mast cells,WBCsFiber types: collagen, elastic, reticularRich supply of nerves and vesselsCritical role in temperature regulation (thevessels)Two layers (see next slides)

Papillary areolar connective tissue; includes dermalpapillaeReticular reticulum (network) of collagen andreticular fibers


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*Dermis layers

*

*

*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 ridgesElevate the overlying epidermis into epidermal ridges

Are sweat films because of sweat pores Genetically determined

Flexion creasesDeep dermis, from continual folding

FibersCollagen: strength and resilienceElastic fibers: stretch-recoil

Striae: stretch marksTension lines (or lines of cleavage)

The direction the bundlesof fibers are directed

The dermis is the receptivesite for the pigment of tattoos


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Hypodermis

Hypodermis (Gk) = below the skin Subcutaneous (Latin) = below the skin

Also called superficial fascia fascia (Latin) =band; in anatomy: sheet of connective

tissue

Fatty tissue which stores fat and anchors

skin (areolar tissue and adipose cells)Different patterns of accumulation(male/female)


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Skin appendages

Derived from epidermis but extend intodermis

IncludeHair and hair folliclesSebaceous (oil) glands

Sweat (sudoiferous) glandsNails


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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 papil lai s conn ec t ive

t i ssue ________________

Hair bulb:epithel ial cel ls

sur roundingpapil la


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Functions of hairWarmth less in man than other mammals

Sense light touch of the skinProtection - scalp

Parts

Root 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 hairVellus: fine, short hairsIntermediate hairs

Terminal: longer, courser hairHair growth: averages 2 mm/week Active: growingResting phase then shed

Hair lossThinning age relatedMale pattern baldness

Hair color Amount of melanin for black or brown; distinct form ofmelanin for redWhite: decreased melanin and air bubbles in themedullaGenetically determined though influenced byhormones and environment


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Sebaceous (oil) glands

Entire body except palms and solesProduce sebum by holocrine secretionOils and lubricates


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Sweat glands

Entire skin surfaceexcept nipples andpart of externalgenitalia

Prevent overheating500 cc to 12 l/day!(is mostly water)Humans mostefficient (onlymammals have)Produced inresponse to stressas well as heat


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Types of sweat glandsEccrine or merocrine

Most numerousTrue sweat: 99% water, some salts, traces of wasteOpen through pores

Apocrine Axillary, anal and genital areas onlyDucts open into hair follices

The organic molecules in it decompose with time - odorModified apocrine glands

Ceruminous secrete earwaxMammary secrete milk


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Disorders of the integumentary system

BurnsThreat to life

Catastrophic loss of body fluidsDehydration and fatal circulatory shockInfection

TypesFirst degree epidermis: redness (e.g. sunburn)

Second degree epidermis and upper dermis: blisterThird degree - full thickness

InfectionsSkin cancer


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BurnsFirst-degree(epidermis only; redness)

Second-degree(epidermis and dermis,with blistering)

Third-degree(full thickness, destroyingepidermis, dermis, often partof hypodermis)


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Critical burns

Over 10% of thebody has third-degree burns25 % of the bodyhas second-degree burns

Third-degreeburns on face,hands, or feet

Estimate by rule of 9s


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Tumors of the skinBenign, e.g. wartsCancer associated with UV exposure(also skin aging)

Aktinic keratosis - premalignantBasal cell - cells of stratum basaleSquamous cell - keratinocytesMelanoma melanocytes: most dangerous;recognition:

A - A symmetryB - B order irregularityC - C olors

D -D

iameter larger than 6 mm

Ski C


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Basal cell carcinoma

Sqaumous cell carcinoma

Melanoma

Skin Cancer

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