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Tissues Classification :

Tissues Classification :. Epithelial tissue : cell layers shape of cells Connective tissue : loose dense regular irregular Nervous tissue : Muscle tissue :. Epithelium Principal Characteristics:. Avascular tissue Special junctions Exhibit functional distinct surface domains

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Tissues Classification :

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  1. Tissues Classification : • Epithelial tissue : • cell layers • shape of cells • Connective tissue : • loose • dense • regular • irregular • Nervous tissue : • Muscle tissue :

  2. Epithelium Principal Characteristics: • Avascular tissue • Special junctions • Exhibit functional distinct surface domains • epithelioid tissues (without free surface) • Attached to basement membrane

  3. Functions of Epithelium : • Barrier • Secretory • Secretory and Absorptive • transport system • receive sensory stimuli

  4. Classification of Epithelium • Simple • squamous • cuboidal • columnar • pseudostratified • stratified • squamous • cuboidal • columnar • transitional

  5. Classification by Locations • Epithelium • Endothelium • Mesothelium

  6. Basement Membrane • LM : • staining technique : PAS stain • EM : • lamina densa (basal lamina) • lamina lucida • Anchoring fibrils (type IX collagen) • External lamina : nonepithelial cells

  7. Functions of Basal Laminae • Structure attachment • Compartmentalization • Filtration • Polarity induction • Tissue scaffolding

  8. Composition Basal Laminae • Type IV collagen • Proteoglycans : negative charge • Laminin : lamina lucida to lamina densa • Entactin and Fibronectin • Anchoring filiment (type VII collagen) • Reticular lamina (type III collagen)

  9. Intercellular Junctions • Terminal bar : junctional complex • zonula occudens : tight junction • selective passage of substances • aonula adherens : band-like junction • lateral adhesion • macula adherens : desmosome • attachment plaque • intermediate line • hemidesmosome : basal cell surface

  10. Cell Surface Modifications • Microvilli : striated border ; brush border • Stereocilia : only in ear and epididymis • Cillia • Lateral and basal cell surface folds and processes

  11. Microvilli • Structures : • actin (microfilament) • terminal web • Functions : • increase the free surface : • absorption • transport fluid • Special name : • striated broder : intestinal absorptive cell • bursh border : kidney tubule cell

  12. Stereocilia • Ductus epididymis : • unusually long microvilli • lack notable internal structural features • absorption • Sensory epithelium of ear : • uniform in diameter • posses an internal filamentous structure • serve as receptor

  13. Cilia : Motile Cytoplasmic Structures • Basal bodies : • procentriole : replication of centriole • Nne triplets • Cilia : • 9+2 arrangement • Movement : metachronal rhythm • effective stroke • recovery stroke

  14. Lateral and Basal Surface Fold • Lateral surface fold : • functions : • increase lateral surface • fluid transport • Basal surface fold : • functions : • active transport • position : • kidney : proximal and distal tubules • salivary gland : striated duct

  15. Glands • Exocrine gland : • secrete by a duct system • Endocrine gland : • lack a duct system : by bloodstream • products : hormones • Paracrine : • target in same tissue • by diffusion

  16. Exocrine Glands • By cell numbers : • unicellular glands • multicellular glands • By duct branched : • simple • compound • By secretory portion shape : • tubule • alveolar or acinar • tubuloacinar

  17. Exocrine Gland Classification • Simple tubular • Simple coiled tubular • Simple branched tubular • Simple branched acinar • Compound acinar • Compound tubuloacinar

  18. Exocrine Products • Mucous secretions : • extensive glycosylation proteins • PAS positive • lost during routine tissue preparation • nucleus : usually flattened at the base of cell • Serous secretions : • poor glycosylation (or nonglycosylation) proteins • secrertory granules well preserved • neucleus : appear round or oval • may form demilunes

  19. Ectodermal Derviations of Epithelium • Surface ectoderm : • epidermis • cornea and lens epithelia • enamel organ and enamel • components of the inner ear • Neuroectoderm : • neural tube • neural crest

  20. Mesodermal Derviations of Epithelium • Epithelium : • kidney • gonads • Mesothelium : • Endothelium : • cardiovascular vessels • lymphatic vessels • Epithelioid : lack a surface location • adrenal cortex, Leydig cell (testis), lutein cell (ovary) • endocrine componemts

  21. Endodermal Derviations of Epithelium • Respiratory system epithelium : • Alimentary canal epithelium : • Extramural digestive gland epithelium : • Thyroid, parathyroid and thymus gland epithelium components • Tympanic cavity and auditory (Eustachian) tube epithelium • Adenohypophysis

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