組胚學英文教學課件肌組織MuscleTissue

1、Chapter 6Muscle tissueIntroduction of muscle tissue1. Muscle tissue muscle cellsIntroduction of muscle tissue1. Muscle tissue muscle cellsmuscle fiber (myofiber) = muscle cellsarcolemma = cell membranesarcoplasm = cytoplasm sarcoplasmic reticulum = sERIntroduction of muscle tissue2. Classification o

2、f muscle tissue Skeletal muscleCardiac muscleSmoothmuscleIntroduction of muscle tissue2. Classification of muscle tissue Skeletal muscle -Cardiac muscleSmooth muscle-Muscle tissuestriated muscleunstriated musclevoluntary muscleunvoluntary muscleSkeletal muscleSkeletal muscleepimysiumperimysiumendomy

3、siumsarcoplasmSkeletal muscleEpimysiumPerimysiumEndomysiumSarcoplasm - C.T.Cell membraneLM of skeletal muscle Longitudinal section: long cylindrical fiber multinucleate, ovoid, peripherally-located periodic cross striationTansverse section: multinucleate, ovoid, peripherally-locatedHow to form perio

4、dic cross striation of skeletal muscle ?myofibrilHow to form periodic cross striation of skeletal muscle ?myofibrilZ lineZ lineH bandHow to form periodic cross striation of skeletal muscle ?myofibril明帶暗帶肌原纖維How to form periodic cross striation of skeletal muscle ?myofibrilLight band(I band)Dark band

5、(A band) SarcomereThe segment of a myofibril between two adjacent Z lines.It is composed of 1/2 I band+A band+1/2 I band. It is the structural and functional unit of the myofiber.EM of skeletal muscle 1.Myofibril - thick myofilament thin myofilament thick myofilamentdistribution: total A bandcompone

6、nt: myosin thin myofilamentdistribution: attach to Z line, extend to the edge of H bandcomposed of actin tropomyosin troponin ActinSpherical actin monomers polymerize to form a double-stranded helix.Each actin monomer contains a binding site for myosin. Actin monomer TropomyosinA long, thin molecule

7、 located in the groove between the two twisted actin strandsMask the myosin-binding site on the actin molecule Myosin-binding sitetropomyosin TroponinA complex of three subunits TnC: bind calcium ions TnT: attach to tropomyosin TnI: inhibit the actin-myosin interaction troponinEM of skeletal muscle

8、1.Myofibril - thick myofilament thin myofilament2. Transverse tubule (T tubule)Tubular invaginations of the sarcolemma, extending transversely into the muscle cell Distribution: AI junctionsFunction: transfer impulses from sarcolemma to sarcoplasm3. Sarcoplasmic reticulumSpecialized sER in muscle fi

9、bersFunction: Ca2+ pump on membrane - store and release Ca2+Mostly run parallel to myofibrilslongitudinal tubule (L tubule)Terminal cisternae: both ends of L tubule enlarge to form a blind tubule which run parallel to T tubule Triad: the complex of T tubule and the two adjacent terminal cisternaeEM

10、of skeletal muscle Cardiac muscleLM of cardiac muscle Longitudinal sectiontransverse sectionLongitudinal section: Short, cylindrical cells with branches 1-2 ovoid nuclei, centrally-located cross striations, but not prominent Intercalated disc: - dark-staining transverse lines between adjacent cardia

11、c myofiberTransverse section:1-2 ovoid nuclei, centrally-locatedLM of cardiac muscle What are the following pictures?EM of cardiac muscle Skeletal muscleCardiac muscleEM of cardiac muscle Skeletal muscleCardiac muscleEM of cardiac muscle Skeletal muscleCardiac muscle Myofibrils are separated by numo

12、urous Mit. T tubule: thicker, at the level of Z line L tubule: not well developed Terminal cisternae: smaller Diad: T tubule + 1 terminal cisterna intercalated diskEM of cardiac muscle # *Intercalated disc The junction between adjacent cardiac muscle cells, with intermediate junction & desmosome in transverse portion for firm connection; with gap junction in longitudinal portion for transferring information & impulse, which play an important role in synchronous con