组胚学课件：Muscular tissue

1、1,Muscular Tissue,20140415,2,Overview 1) components: -cell: muscle fiber-myofiber elongated thread-liked Sarcolemma（肌膜） Sarcoplasm（肌质） Sarcoplasmic reticulum（肌质网）: SER -extracellular G.S: CT with BV, LV and N,3,2) classification According to the structure and function skeletal muscle (骨骼肌): striated

2、, voluntary cardiac muscle (心肌): striated, involuntary smooth muscle (平滑肌): unstriated, involuntary,4,Skeletal muscle,5,Epimysium（肌外膜）: DCT Perimysium（肌束膜） Endomysium（肌内膜）,6,LM: long cylindrical 10-100um in diameter, 1-40mm long multinucleate, nuclei are ovoid, distributed under sarcolemma filled wi

3、th longitudinal parallel- arranged myofibrils,7,Skeletal Muscle,Cells are long multinucleate “cylinders”,8,9,Identify: Endomysium, Perimysium, myofiber and fascicle,Endomysium,Perimysium,Myofiber,Fascicle,10,Endomysium: connective tissue, nutrient capillaries, nerve endings and around each myofiber

4、a basal or external lamina,11,Myofiber,12,Myofibril: 1-2um in diameter cross striation: light band -I band dark band- A band -A band: M-line, H-band -I band: Z-line,13,Definitions,Isotropic (各向同性),Anisotropic (各向异性),14,A band : Anisotropic (各向异性) I band: Isotropic (各向同性),15,H Band is light and in th

5、e center of the A Band,16,Sacromere（肌节）: 1/2 I +A + 1/2 I the smallest structural and functional unit of myofibril,17,1.Transverse tubule (T tubule): 横小管 definition: sarcolemma invaginate into sarcoplasm to form a transverse distributed tubular system location: A-I junctional part function: transfer

6、 the information into cytoplasm,EM:,18,2.Sarcoplasmic reticulum: 肌质网 smooth endoplasmic reticulum longitudinal tubule ( L tubule ) terminal cisternae (终池) Triad (三联体): one T-tubule +two terminal cisternae calcium pump proteins store and release calcium ions,19,20,3.Myofibril (肌原纤维) thick myofilament

7、 thin myofilament,21,Skeletal Muscle,Organizational Hierarchy,Muscle is composed of fascicles,Fascicle (smallest) is composed of myofibers,Myofiber is composed of myofibrils,Myofibril is composed of myofilaments,22,Thick myofilament 1.5 um long, 15 nm in diameter composed of myosin (肌球蛋白) -rob: in b

8、undles -head: cross bridge- binding site (ATPase activity),23,Thin myofilament 1 um long, 5 nm in diameter A. Actin (肌动蛋白)- binding site B. Tropomyosin (原肌球蛋白) C. Troponin (肌原/钙蛋白) -Tn T: bind to tropomyosin -Tn C: binds to calcium ions -Tn I: inhibit actin-myosin interaction,24,Is cross banding evi

9、dent at the level of the myofibril?,Define a sarcomere.,A sarcomere is that portion of the contractile apparatus between and attaching to two Z lines.,Myofibril,25,Myofibril,The sarcomere is the smallest contractile unit. It consists of a precisely organized array of myofilaments.,Thick myofilaments

10、 consist of myosin. Myosin is ONLY found in the A Band,26,Myofibril,Thin myofilaments consist of Actin, tropomyosin and troponin. Thin myofilaments are found in BOTH the A Band and I Band,27,Myofibril,M Line, in the center of the H Band, consists of proteins that hold myosin filaments together.,28,M

11、yofibril,Z Line.,29,Micrograph Provided by Ernest Whitter,Electron Micrograph of Human Skeletal Muscle,Dark granules are glycogen,Myofibril,30,Micrograph Provided by Ernest Whitter,Electron Micrograph of Human Skeletal Muscle,Sarcomere,31,Micrograph Provided by Ernest Whitter,Electron Micrograph of

12、Human Skeletal Muscle,A Band,32,Micrograph Provided by Ernest Whitter,Electron Micrograph of Human Skeletal Muscle,I Band,Z Line,M Line in H Band,33,Sliding filament hypothesis (肌丝滑动学说),34,Cardiac muscle,35,LM short column in shaped, 100um long,15um in diameter, with branches 1-2 ovoid nuclei, centr

13、ally-located striated, but no very clear intercalated disc,36,EM T tubule at Z-line level less terminal cisternae diad(二联体): one T-tubule + one terminal cisternae Numerous mitochondria,37,intercalated discs,38,39,Smooth muscle,40,LM elongated, spindle-shaped cells, 8um in diameter, 200( 20-500)um long rob-liked or ovoid nucleus no striation, no myofibril,41,Smooth Muscle,Longitudinal Section,Cross Section,42,EM caveola: sarcolemme invaginate into cytoplasm dense patch (密斑): under sarcolemma dense body (密体): in sarcoplasm intermediate filament: /composed of desmin(结蛋白) /10nm i