VC Supplementary Lesson: Tissues


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The lesson discusses about animal tissues.

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VC Supplementary Lesson: Tissues

  1. 1. This PowerPoint Presentation is made by ARLENE G.SALUSTIANO through compilation of different internetsources.The right of ownership is reserved to the maker of thepresentation.This can not be used without permission from the owner.For teaching use only and limited for school use.The owner respects the copyright ownership of theinternet sources herein; hence it cannot be published foruse outside.
  2. 2. Systems composed of Organs Organs composed of Tissues Tissues composed of CellsTissues - major components ofsystems and organs
  3. 3. Types of Tissue:Muscular tissue: Muscular tissues makeup the major part of the soft tissues ofthe body & by means of its contractionpower helps in locomotion. e.g. – Skeletalmuscle, cardiac muscle.Nervous tissue: Nervous tissue is highlyspecialized tissue which controls & co-ordinates the body functions by formingnervous system. e.g – Neuralgia, Whitematter, Grey matter.
  4. 4. Connective tissue: Connectsdifferent structures of the body &also helps to provide framework ofthe body. e.g. – Blood, Bones.Epithelial tissue: are formed of cellsthat line the cavities in the body andalso cover flat surfaces. Of the fourmajor tissue types found in thehuman body epithelial cells are by farthe most prolific.
  5. 5. The muscular, connective andnervous tissues mentioned onthe previous slides will bediscussed further in theOrgan System discussion forthat particular organ.The succeeding slides willfocus on Epithelial tissues.
  6. 6. Special types of tissuesEpithelial tissue: Covering the external &internal body surfaces. e.g. – Skin,internal covering of (Gastro-intestinalTract) GIT.1) Epithelial - linings and coveringsa) simple - single layer (found in the intestineb) stratified - multiple layersc) cuboidal - cube shaped (secretory)d) columnar - column shaped (found in the intestine)e) squamous - flat for diffusion (found in the lungs)
  7. 7. An epithelium may be one or morecells thick and the cells may be ofvery different shapes and sizes.Some are thin and flat. They formpavement or squamous epitheliumwhich is found, for example, in thelining of parts of the kidney tubes.
  8. 8. Where Are Epithelial Cells Found?Epithelial cells line the major cavities ofthe body.Epithelia form the structure of the lung,including the alveoli or air sacs where gasexhange occurs.• Cells line most organs, such as the stomach and small intestine, kidney, and pancreas. They also line the esophagus.• Cells are also found in ducts and glands, like the bile duct and sailvary glands.
  9. 9. •The skin is made of epithelial cells.Its striated layers demonstrate theextensive morphology of epithelia.•Capillary beds are made ofepithelium.•Epithelia is the first type of cell todifferentiate in the embryo. Thisoccurs during the eight-cell stage.
  10. 10. •Epithelia can specialize to act assensory receptors. They form tastebuds, line the nose, and are in the ear.They are also found in the eye.•Female reproductive organs are linedwith ciliated epithelial cells.
  11. 11. How Do Epithelial Cells Differ From Other Cells? Avascular •Capillaries do not reside within epithelial cell tissues. Sensory •Endings of neurons are present within epithelial cell tissues •Perceive external stimulus (i.e. Tactile)
  12. 12. Gliding surface layer•Epithelial cells slough off and glide inorder to replace dead cells.•This function allows epithelial cells tomaintain a closed barrier to the externalenvironment.
  13. 13. Transitional•Multi-layered epithelia are able tostretch•Allows the urinary bladder to distendedor contracted without compromising itTight barrier•tight junctions•Epithelium is held together more tightlythan other cells•Aids cells in withstanding mechanicalstress
  14. 14. Different from endothelial cells•Endothelial cells line the insides ofstructures that aren’t exposed to the“outside”•Ex. Blood vessels
  15. 15. Structure of Epithelial TissueEpithelial cells are bound together insheets of tissue called epithelia. Thesesheets are held together through severaltypes of interactions, including tightjunctions, adherence, and gap junctions.One type of junction found only inepithelium is the tight junction, which isconsidered by most scientists as theclosest junction in the world. /index.html
  16. 16. Tight junctions act as the delineationbetween the apical (upper) and basal(lower) regions of an epithelial cell inconjunction with polarization betweenthe two regions. Epithelium issupported on the basal side by abasement membrane called the basallamina.
  17. 17. Below the basal lamina lies the capillarybed, which provides epithelia withrequired nutrients and disposal of wasteproducts. In addition, the nucleus in theepithelial cell is usually found closer tothe basal surface than the apicalsurface.
  18. 18. When the cells of squamousepithelium have wavy outlines (e.g.,cells lining the blood vessels) they aresaid to be tessellated. Other cells areapproximately as wide as they are tall.These form cuboidal or cubicalepithelium which is found in manyglands (e.g., the liver).In columnar epithelium the cells aretall and column-shaped. Suchepithelium lines most of the gut.
  19. 19. If columnar cells bear cilia theepithelium is known as ciliatedcolumnar epithelium. Ciliated cellsoccur in the lining of the trachea(windpipe). The cilia beat to helpremove dirt particles.The outer cells of the skin and thelining of the cheek form stratifiedsquamous epithelium. It is also foundin the front, transparent layer of theeye (cornea).
  20. 20. A layer or sheet of cells that lines abody cavity; they show an unusuallyhigh cell-turnover rate. Epithelial cellsare held together by a small amountof cementing substance. The outercovering of the body (the skin), thelining of the gastrointestinaltract and other organs, such asthe lungs and blood vessels, and theinner lining of the ducts in glands areexamples.
  21. 21. Below most epithelia is a thin sheetof connective tissue, the basementmembrane. The free surface of mosttypes of epithelium (the surface that isnot attached to other tissue) may haveon it short hair-like structurescalled cilia.
  22. 22. The ones forming the outercovering of the skin are mainlyprotective and water-resistant,while the cells of the lung liningproduce the wet mucusin whichoxygen dissolves before passing tothe blood.
  23. 23. When the epithelium is several layersof cells thick it is said to stratified.The cells of epithelia may serve verydifferent purposes. Those liningthe salivary glands, and the glands inthe intestine for example, producethe enzymes that digest food.
  24. 24. Functions Boundary & Protection Epithelial cells cover the inner and outer linings of body cavities, such as the stomach and the urinary tract. As the barrier between the outside world’s contaminants and the body, these cells replicate often to replace damaged or dead cells.
  25. 25. Many layers provide betterprotection, meaning if one layer islost, the underlying tissue is stillprotected. Tight junctions, arevery difficult to alter or break andcreate a semi-permeable seal thatfew macromolecules or microbescan penetrate.
  26. 26. Sensory Although epithelial cells are avascular, they are innervated. These nerve endings provide signals for sensory sensations such as taste, sight, and smell. These cells exhibit specialized structure to fulfill their function.
  27. 27. AbsorptionThe ability of certain epithelial cells touse active-transport systems, asdiscussed above, enables them toabsorb filtered material, such asglucose from the lumen of theintestine, which can then be circulatedto the rest of the body. Cells are alsoable to endocytose other materials thatare necessary for cell growth andsignaling. For more information,see transcytosis.
  28. 28. TranportationSome epithelial cells, such as the ones foundon the intestinal lining, aid in thetransportation of filtered material throughthe use active-transport systems located onthe apical side of their plasmamembranes. For example, the glucose-Na+pump located within certain domains of theplasma membrane of epithelial cells lining theintestine enable the cells to generate Na+concentration gradients across their plasmamembranes, which provides the energyneeded to uptake glucose, from the lumen ofthe intestine.
  29. 29. The glucose is then released into theunderlying connective tissues and istransported into the blood supplythrough facilitated diffusion down itsconcentration gradient.
  30. 30. Secretion & LubricationSome epithelial cells, such as the gobletcells, secrete fluids that are necessary forother processes such as digestion,protection, excretion of waste products,lubrication, reproduction, and theregulation of metabolic processes of thebody. As part of its excretory role, certainepithelial cells secrete mucus, whichlubricate the body cavities (i.e. peritoneum,pericardium, pleura, and tunica vaginalis)and passageways that they line.
  31. 31. In the trachea, goblet epithelial cellssecrete mucous which provides thelubrication to aid ciliated epithelialcells in sweeping bacteria and dustaway from the lungs. In addition, typeII alveolar cells excrete pulmonarysurfactant, which decreases surfacetension, allowing for normal lungfunction.
  32. 32. MovementSome epithelial cells have cilia,which aid in moving substancesin the lumen by creating acurrent via coordinated"sweeping" of the cilia.
  33. 33. In the trachea, goblet epithelial cellssecrete mucous which provides thelubrication to aid ciliated epithelialcells in sweeping bacteria and dustaway from the lungs. In addition, typeII alveolar cells excrete pulmonarysurfactant, which decreases surfacetension, allowing for normal lungfunction.
  34. 34. For instance, ciliated columnarepithelial cells are instrumentalin the movement of the ovumthrough the Fallopian tubes tothe uterus.
  35. 35. 1. What are the four major classification of tissues?2. For each kind of tissues give at least three organs where it can be found.
  36. 36. page/jpitocch/genbio/organiza tionnot.html