大连医科大学：《组织胚胎学》课程教学课件（英文讲稿）06.Muscular tissue

Muscular Tissue

Muscular Tissue uscular Tissue uscular Tissue

ContentsMuscular TissueSkeletal MuscleCardiac MuscleSmooth Muscle

 Skeletal Muscle  Smooth Muscle Contents  Cardiac Muscle  Muscular Tissue

IntroductionMuscleCompositionMuscle cellsConnectivetissuecap.,lymphaticv,nfClassificationStriated mSkeletal m → voluntary mCardiacminvoluntary mUnstriatedm.Smoothm

Introduction Composition Muscle cells Connective tissue cap., lymphatic v, nf Classification Striated m Skeletal m Striated m Skeletal m Cardiac m Cardiac m Unstriated m Smooth m Unstriated m Smooth m voluntary m. voluntary m. involuntary m involuntary m Muscle

ActivityMuscletypesSkeletalmuscleCrosssectionsStrong,quickdiscontinuousvoluntarycontractionStriatedmNucleiCardiacmuscleStrong,quickcontinuousinvoluntarycontractionIntercalateddisksSmoothmuscleWeak,slowinvoluntary0contractionE

Striated m

SpecificterminologyMuscle cell -....- muscle fibreMembrane ..... sarcolemmaCytoplasm .... sarcoplasmSER ---..-Ssarcoplasmic reticulum

Muscle cell - muscle fibre Membrane - sarcolemma Cytoplasm - sarcoplasm SER - sarcoplasmic reticulum Specific terminology

SkeletalMusclestructureShape: Long, cylindrical cellsNu:flattened,MultinucleatedbeneathsarcolemmaSarcoplasm: myofibrils;crossstriationsalternatingdark and light bands

structure Shape: Long, cylindrical cells Nu: flattened, Multinucleated, beneath sarcolemma Sarcoplasm: myofibrils; cross striations alternating dark and light bands  Skeletal Muscle

1)myofibrilsAbandZ lineIbandLMlightband=Ibanddarkband=AbandA band, I band, Z line,H band, M lineSarcomereSarcomere:1/2 /+ A + 1/2 Ishortestcontractileunitofskeletalmuscle.MusclefibreMyofibrils

A band, I band, Z line, H band, M line Sarcomere: 1/2 I + A + 1/2 I shortest contractile unit of skeletal muscle. A band Z line I band • light band= I band •dark band =A band LM 1) myofibrils Sarcomere

EMlongparallel,cylindricalfilamentousbundles(thin & thick)consisting of two types of myofilamentAHZ line1MlineHSarcomere

EM long , parallel , cylindrical filamentous bundles consisting of two types of myofilament (thin & thick) H Z line A I M line Z Z H Sarcomere

a.Thickfilamentsoccupying A band, fixation M linemyosinmoleculesrods overlap; globular heads direct toward eitheroftheendsformingcrossbridgesandhaveATPaseactivitySarcomereAbandHbandZdiskTitinNebulinm band

a. Thick filaments occupying A band, fixation M line myosin molecules rods overlap; globular heads direct toward either of the ends forming cross bridges and have ATPase activity

b.Thin filamentsOneendisattachedtothe Zline,theotherreachtothelateralendofHbandIbandAbandIbandendend-Composed ofHzoneactin,ActinfilamentThickfilamenttropomyosin+end-+endtroponin (Tnl,TnT,TnC)DisActinmonomersTropomTroponithin.filaTroponinsubunitsSwitahpartofTnlMyosin-bindingpartofthefilamentthe filamentTnoTnT

b. Thin filaments One end is attached to the Z line, the other reach to the lateral end of H band Composed of actin, tropomyosin troponin (Tnl,TnT,TnC)