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Stratified Epitheium by Dr Roomi

Apr 06, 2018

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Mudassar Roomi
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    STRATIFIED EPITHELIUM

    BY

    DR. MUDASSAR ALI ROOMIDR. MUDASSAR ALI ROOMI(MBBS, M. PHIL.)

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    TYPES OF STRATIFIED EPITHELIUM

    Where body linings have to withstand wearand tear, the

    epitheliaarecomposedofseverallayersofcellsandare

    thencalledcompoundorstratifiedepithelium.

    Also called as multi-laminarepithelium. Stratifiedepitheliaarenamedafter theshapeofthecells in

    the topmost layer.

    Typesofstratifiedepitheliaareasfollows:

    1. Stratified Squamous Epithelium

    2. Stratified Cuboidal Epithelium

    3. Stratified Columnar Epithelium

    4. Transitionalepithelium

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    Stratified squamous epithelium

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    Stratified Squamous Epithelium

    multi-layered epithelium.

    flat, scale-like surface cells.

    basal layer is in contact with basal lamina. provideprotectionagainst:

    mechanical friction - rubbing and physical trauma

    from

    external sou

    rces chemical damage - environmental and internal

    chemicals degrading theepithelial lining

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    Stratified Squamous non- keratinized

    Epithelium

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    Stratified Squamous non- keratinized

    Epithelium

    The lining of theesophagus is an example ofa

    non-keratinizedor "moist" stratified

    epithelium. It provides protection to

    esophagus from stomachacid.

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    Stratified Squamous keratinized

    Epithelium

    themost apical layers ofcells are dead and losetheir nucleus and

    cytoplasm

    , insteadcontain a tough,resistant protein calledkeratin.

    This specializationmakes theepitheliumwaterproof, so is foundin themammalian skin.

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    Stratified Cuboidal Epithelium

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    Stratified Cuboidal Epithelium

    rare

    cube-shaped surface cells.

    commonly cellsmakeup two layers

    Present in larger ducts of sweat glands,

    mammary gland and salivary glands in the

    m

    ou

    th

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    Stratified Columnar Epithelia

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    Stratified Columnar Epithelia

    Rare type ofepithelium.

    column-shaped surface cells.

    found inlining ofprostatic,membranous andpenileurethra.

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    Transitional epithelium

    (Urothelium)

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    Transitionalepithelium (also known as urothelium) is atype of tissue consisting ofmultiple layers ofepithelialcells which can contract and expand.

    These cells, part of theepithelium, arefound inrenalcalyces, renal pelvis theurinary bladder, in theureters.

    Function:

    The transitional epithelium cells accommodate

    flu

    ctu

    ation ofvolum

    e of the liqu

    id in an organ or tu

    be,suchas theurinary bladder

    protects against the caustic effects ofurine.

    Transitional epithelium (Urothelium)

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    FunctionsofEpithelial Tissue Protection : Epithelial cells in the skinprotect underlying tissue from

    mechanical injury, harmful chemicals, invading bacteria and from excessive

    loss of water.

    Sensation: Specialized epithelial tissue containing sensory nerveendings is

    found in the skin, eyes, ears, noseand on the tongue.

    Secretion: In glands, epithelial tissue is specialized to secrete specific

    chemical substances suchas enzymes, hormones and lubricating fluids.

    Absorption Certain epithelial cells lining the small intestineabsorb

    nutrients from the digestion of food.

    Excretion Epithelial tissues in the kidney excrete waste products from the

    body and reabsorb needed materials from the urine. Sweatis also excreted

    from the body by epithelial cells in the sweat glands.

    Diffusion Simpleepitheliumpromotes the diffusion of gases, liquids and

    nutrients. Because they form sucha thin lining, they are ideal for the

    diffusion of gases (e.g. walls of capillaries and lungs).

    Cleaning Ciliated epitheliumassists in removing dust particles and foreign

    bodies whichhaveentered theairpassages.