GENERAL HISTOLOGY 4. Muscular Tissue · GENERAL HISTOLOGY 4. Muscular Tissue Dr. ManalOthman...
Transcript of GENERAL HISTOLOGY 4. Muscular Tissue · GENERAL HISTOLOGY 4. Muscular Tissue Dr. ManalOthman...
AnatomyDepartmentCMMS,AGU
GENERAL HISTOLOGY4. Muscular
TissueDr. Manal Othman
Biology-232
• ResponsibleforMOST typesofBODYMOVEMENT
• MadeupofgroupsofelongatedMUSCLE cellswithcontractilefilaments
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Terminologies• Sarcolemma• Sarcoplasm• Sarcoplasmic reticulum• Sarcomere
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Classification:Morphology
• STRIATED– Havecharacteristicalterationsofdarkandlightbands,Nonstriated
– Nostriations– Locatedinwallsofbloodvessels,viscera.
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Classification:Function
• VOLUNTARY– Consciouscontrol
• INVOLUNTARY– Noconsciouscontrol
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Classification:MorphologyandFunction
• 3types,morphology/function
SKELETALMUSCLE
CARDIACMUSCLE
SMOOTHMUSCLE
Strong,quickdiscontinuousVOLUNTARYCONTRACTIONStriatedcylindricalnonbranching
Strong,quickcontinuousINVOLUNTARYCONTRACTIONStriated
cylindricalbranchingWeak,slowINVOLUNTARYCONTRACTIONnon-striatedSpindleshape 6
SKELETALMUSCLE• Longmusclefibers• Cylindrical,
multinucleated cells• Ovalnucleifoundat
periphery ofcell,underthecellmembrane
• Striations present• Pinktoredincolor
duetorichvascularsupplyandpresenceofmyoglobin pigments
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SKELETAL MUSCLE FIBERS (H&E picture)
SKELETAL MUSCLE FIBERS
Connectivetissuecoverings
1.Epimysium(denseirreg CT)2.Perimysium
(invagination– Ms bundles)3.Endomysium(delicateCT)
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OrganizationofSKELETALMUSCLEFIBER
• ZLINEordisk• ABAND• IBAND• HBAND–
palearea,centerofAband
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Sarcomere -Smallestsubunitofcontractileapparatus
SKELETAL MUSCLE FIBERS (Sarcomere)
Electronmicroscopicpicture
MOTORENDPLATE
• Myoneuraljunction• Branchingmyelinatedmotornerves– “dilatedtermination”
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CARDIACMUSCLE
• Cross-striatedbandingpattern
• 1or2centrally-locatedpale-stainingnuclei
• Endomysial CT– hasarichcapillarynetwork
• structure&function:diads(1t-tubule&1sarcoplasmicreticulumcisterna)
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CARDIAC MUSCLE FIBERS• Striated, branched cells with intercalated disks
(junctional complexes).
• Contain 1–2 central large pale nuclei.
• Rhythmic contraction.
CARDIAC MUSCLE FIBERS (H&E picture)
§ Only1or2centrally- locatedpalestainingnuclei
§ Containsnumerousmitochondria-occupy40%ormoreofthecytoplasmicvolume
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Electronmicroscopicpicture
§ INTERCALATEDDISK–representjunctionalcomplexesbetweenadjacentcardiacmusclecells
§ 3mainjunctionalspecializations1.Zonulaadherens:(Fasciae
adherentes) – mostprominentfoundintransverseportions,servesasanchoringsitesforactinfilamentsofterminalsarcomeres
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2.Maculaeadherentes(desmosomes)– foundintransverseportions,bindcardiaccellstogethertopreventtheirpullingapartunderconstantcontractileactivity
3.Gapjunction – foundinlateralportions,provideioniccontinuitybetweenadjacentcells
SMOOTHMUSCLE
• Elongated non-striated spindle shaped cells
• Length: 20 um (small bld vessels) & 500 um(pregnant uterus)
• Each cell – oval nucleus located in center
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SMOOTH MUSCLE FIBERS• Elongated, nonstriated, fusiform cells with single
central nucleus (folded and tapers).
• Located in walls of respiratory, GIT, urinary, and blood vessels
SMOOTH MUSCLE FIBERS (H&E picture)
ORGANELLES• Mitochondria
• Sarcoplasmic reticulum –branching network of cisternae
• Transverse tubules – finger-like invaginations of sarcolemma, regulation of Ca+
– Skeletal muscle – TRIAD 2SR + 1TT (Present at AI junction)
– Cardiac muscle – DIAD 1SR + 1TT (present at Z line)
– Smooth muscle – NO T-tubules
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CARDIACMUSCLE
– virtuallynoregenerativecapacitybeyondearlychildhood
- Defectsordamage(eg.infarcts)aregenerallyreplacebyproliferationofconnectivetissue(myocardialscars)
RegenerationofMUSCLETISSUE
SKELETALMUSCLE
– undergolimitedregeneration,sourceorregeneratingcellsisbelievedtobethesatellitecells
SMOOTHMUSCLE
– capableofactiveregenerativeresponse
- Undergomitosis
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