1. Chapter 6 muscle tissue

2. Composition muscle cell+loose connective tissue ● muscle cell →muscle fiber, sarcolemma, sarcoplasm, sarcoplasmic reticulum ● classification: skeletal muscle, cardiac muscle, smooth muscle striated muscle, nonstriated muscle voluntary muscle, involuntary muscle introduction:

3. skeletal muscle epimysium 肌外膜 perimysium 肌束膜 endomysium 肌内膜 function: supporting connection nourishment protection

4. 1. microstructure: cylindrical: 1 ～ 40mm length, 10 ～ 100µm in diameter elongated nuclei: beneath the sarcolemma myofibril: parallel to long axis light band: isotropic → I band dark band: anisotropic → A band cross striation

5. cross section: Cohnheim field

6. high magnification: A band: H band, M line; I band: Z line sarcomere=1/2 I+A+ 1/2 I structural and functional unit a part of fibril between the neighboring z lines Z线Z线 I带I带 A带A带 M线M线

7. 2. ultrastructure : 1 ） myofibril: myofilaments thick filament : A band 1.5 µ m long 15nm in diameter thin filament: z line 1 µ m long 5nm in diameter one thick filament is surrounded by 6 thin ones one thin filament is surrounded by 3 thick ones

8. molecular structure of myofilaments: 1. thick filament: myosin bean sprout shape : head+ rod ATPase, connecting ATP, head can bend--- combine with actin cross bridge 横桥 头（ ATP 酶） 杆

9. 2. thin filament: actin : globular subunits spiral two strands tropomyosin: two strands of polypeptides covering the active point of actin troponin: TnT 连接亚单位 TnI 连接抑制亚单位, TnC 钙结合亚单位 C T I

10. 2 ). transverse tubule: ● vertical to the axis of the cell ● encircle the boundaries of the A-I bands of each sarcomere function: transmit exciting to each sarcomere T 小管

11. 3). sarcoplasmic reticulum: SER between T tubules surrounded each fibrile longitudinal tubule terminal cisternae 终池 triad : 2 terminal cisternae and T tubule calcium pump=ATPase function: regulate the concentration of calcium in sarcoplasma 肌浆网三联体

12. 3.The contraction mechanism of skehetal muscle sliding filament hypothesis Ca 1234

13. cardiac muscle 1. microstructure: branches intercalated disc ovoid nucleus mitochondria glycogen lipochrome cross striation

14. 2. Ultrastructure characters: myofilament bundles T-tubules at Z line level small terminal cistermae (diad) intercalated disc at z line level

15. intercalated disc transverse position : intermediate junction, desmosome longitudinal position: gap junction function: transmit chemical massage and electric impulse

16. smooth muscle smooth muscle 1. microstructure: spindle shape elongated ovoid nucleus spiral, pleated 20--500 µ m (in pregnant uterus) arrangement: bundle or layers

17. 2. ultrastructure: small vesicle: ( sarcoplasmic reticulum) dense patch ( area), dense body intermediate filaments (10nm ) caveola (T-tubule)

18. contractile unit: thin : thick filaments = 12-30:1 cylindric, 8-16nm, myofilament unit=contractile unit: