Histology
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Histology

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Histology Histology Presentation Transcript

  • TISSUESJaniceV. Ng, MScDepartment of BiologyCAS, UP Manila
  • Tissues “weave” group of cells with a common structureand function held together by intracellular substances
  • Types EpithelialTissues ConnectiveTissues MuscularTissues NervousTissues
  • Epithelial Tissues composed of closely packed cells with very little intercellularsubstance surface epithelia – exposed to air or fluid; continuous withone or more layer of cells base of epithelia usually resting on a basement membrane◦ Basement membrane – separates epithelia from underlyingtissues; never penetrated by blood vessels cover the outside of the body and line organs and cavitieswithin the body wide range of activities:◦ protective covering and lining surfaces (skin), absorption(intestine), secretion (epithelial cells of glands), sensory(neuroepithelium) and contractility (myoepithelial cells). Cell joined together by cellular junctions
  • EpithelialTissuesShapesquamous cuboidal columnarNumbersimple stratifiedStratifiedsquamousPseudostratifiedcolumnarName: Number of layers + shape
  • Example…
  •  Simple epithelium◦ ___ layer of cell◦ Involved in selective diffusion, absorption,secretion◦ Protection? Only minimal
  • Simple SquamousEpithelium• air sacs of lungs, glomeruli,linings of heart, lymphatic andblood vessels• diffusion and filtration
  • Simple CuboidalEpithelium• kidney tubules, ducts andsmall glands and surface ofovary• secretion and absorption
  • Simple ColumnarEpithelium• linings of digestive tract, gallbladder, and excretory ductsof some glands• villi, microvilli, goblet cells• absorption and enzymesecretion
  •  Stratified epithelium◦ ____ layer of cells◦ Mainly for protection◦ Degree of stratification related to the kind ofphysical stresses to which the surface isexposed◦ Name is based on the structure of the ____cells
  • Stratified SquamousEpithelium• keratinized: surface of theskin• nonkeratinized:linings of the esophagus,mouth and vagina• protect underlying tissues inareas subject to abrasion
  • PseudostratifiedCiliated ColumnarEpithelium•True simple epithelium• All cells rest at the basementmembrane• Nuclei disposed at differentlevels• Cilia• Linings of bronchi, uterinetubes, and some regions of theuterus.• propel mucus or reproductivecells by ciliary action.
  • Connective Tissues Provide structural and metabolic supportfor other tissues and organs Usually contain blood vessels Mediate exchange of nutrients,metabolites, waste products betweentissues and circulatory system
  • Connective Tissues Basic Components◦ Cells – scattered through extracellular matrix Fibroblast/fibrocyte, Adipocytes, Mast cells,macrophages, Blood cells◦ Extracellular Matrix Fibers Collagen, Elastin, Reticulin (Type III collagen) Ground Substance - mixture of polysaccharide chains,glycosaminoglycans (GAGs), proteoglycans Structural glycoproteins – mediates interaction of cellswith other constituents
  • ConnectiveTissueConnective TissueProperLoose/AreolarDense ModifiedLooseSpecializedConnectiveCartilageBoneBloodConnectiveTissue Proper - jelly-like extracellular matrixSpecialized ConnectiveTissue - liquid/ semi-solid/ hard solid matrix
  • Loose/ AreolarConnectiveTissue• with numerous fibroblastthat produce collagenous andelastic fibers• subcutaneous layer• wrap and cushions organs
  • Dense Regular ConnectiveTissue• contains densely packedparallel collagen fibers• tendon, ligaments
  • Dense IrregularConnectiveTissue• contains densely packedrandomly arranged collagenfibers• Frog skin
  • Modified Loose ConnectiveTissueAdiposeTissue• subcutaneous layer• cushions, storage of fatsReticularTissue• supports hemopoietic organs
  • CartilageCell component – chondrocytesGround substance – chondroitin sulfate and hyaluronateFibers: collagen, elasticHyaline Cartilage• collagen fibers• cartilage of nose, trachea, larynx• support and reinforcement
  • Elastic Cartilage• collagen fibers and many elasticfibers• cartilage of external ear andepiglottis• maintains shape and allowsflexibilityFibrocartilage• dense collagen fibers• cartilage of intervertebral disc,pubic symphysis and disk of kneejoints• absorbs compression shock
  • BoneCell Components – osteoblasts,osteocytes, osteoclastsGround Substance – calciumphosphate, chondroitin-sulfateand keratan sulfate (hard andmineralized matrix)Fibers: collagen (Type I)
  • BloodGranulocytes AgranulocytesNeutrophil EosinophilBasophilLymphocyteMonocyteErythrocytes Leukocytes
  • MuscleTissueStriated VoluntaryMuscle (SkeletalMuscle)StriatedInvoluntaryMuscle (CardiacMuscle)Non-striatedInvoluntary Muscle(Smooth/VisceralMuscle)*Striations – arrangement of the contractile proteins (actin and myosin)
  • Skeletal MuscleTissue• striated muscle fibers• cylindrical• many peripheral nuclei• skeletal muscles attached tobones• useful for voluntarymovement• sarcolemma• sarcoplasm
  • Cardiac MuscleTissue• striated muscle fibers• branched, with intercalateddisc• uninucleated• involuntary heart movement
  • Smooth MuscleTissue• Spindle-shaped cells• uninucleated• lacks striations• involuntary movement ofvisceral organs and bloodvessels• epimysium, perimysium,endomysium
  • Nervous Tissues Sense stimuli and transmit signals from onepart of the animal to another Functional unit  neuron/nerve cell Smear, Cross section, Longitudinal section
  • NervousTissue (smear)• cell body• nucleus• dendrites and axon• glial cells
  • Axons are bundled together in structurescalled nerves.Longitudinal section• Neurilemma- membrane covering the fiber• Axis cylinder- the central region of the nervefiber• Medullary sheath - thick sheath covering thefiber between the neurilemma and the axiscylinder• Nodes of Ranvier- constrictions in themedullary sheathCross section (not available)• Epineurium - the membrane covering abundle of fascicule of nerve fiber• Perineurium - the membrane covering afasciculus of nerve fiber• Endoneurium - the membrane covering anerve fiber
  • END