Histology of muscle pdf lecture notes by Dr.N.Mugunthan

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Information about Histology of muscle pdf lecture notes by Dr.N.Mugunthan

Published on November 15, 2016

Author: MUGUNTHANDrMugunthan

Source: slideshare.net

1. HISTOLOGY OF MUSCLE TISSUE Lecture By Dr.N.Mugunthan.MS.,DNB. MNAMS., PhD., Associate Professor MGMC&RI

2. Try to identify this slide © Dr.N.Mugunthan 2

3. Objectives • Features of muscle tissue • Types of muscle • Microstructure of each type of muscle • Applied histology • Practical aspects • Summary © Dr.N.Mugunthan 3

4. Muscle tissue • Contractile • Cells – myocytes • Myocytes are elongated – muscle fibres • Developed from – mesenchyme (mesoderm) © Dr.N.Mugunthan 4

5. Types of muscle • Structurally and functionally 3 distinct types of muscle 1. Skeletal muscle 2. Cardiac muscle and 3. Smooth muscle © Dr.N.Mugunthan 5

6. 1. Skeletal muscle • Skeletal muscle or • Striated muscle or • Voluntary muscle • Ex: muscles of Limbs & body wall © Dr.N.Mugunthan 6

7. Skeletal muscle cont…. • Consists of long tubular cells (also called muscle fibers). • Average length 3 cm • (sartorius 30 cm, stapedius 1 mm) • Cell membrane – sarcolemma • Cytoplasm ( sarcoplasm) • Contain many peripherally placed nuclei (up to several hundred). © Dr.N.Mugunthan 7

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9. • Muscle fibers in skeletal muscle occur in bundles, (fascicles) • Connective Tissue Covering a) Epimysium, b) Perimysium c) Endomysium • The connective tissue transduces the force generated by the muscle fibers to the tendons. Skeletal muscle cont…. © Dr.N.Mugunthan 9

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11. • Muscle fibers show characteristic cross- striations. (striated muscle) • Innervated by the somatic nervous system. (Voluntary muscle) Skeletal muscle cont…. © Dr.N.Mugunthan 11

12. Skeletal muscle – cross section skeletal muscle cells ("fibers") skeletal muscle cell nuclei blood vessels interlacing bundles of smooth muscle © Dr.N.Mugunthan 12

13. Skeletal muscle –L.S & T.S © Dr.N.Mugunthan 13

14. Skeletal muscle, L.S. Note the striations. PICROSIRIUS-POLARISED LIGHT (PSP) STAIN, high magnification. © Dr.N.Mugunthan 14

15. Contractile apparatus of skeletal muscle • Regular organization of the myofibrils gives rise to the cross striation • cross striation characterizes skeletal and cardiac muscle. • Sarcomeres © Dr.N.Mugunthan 15

16. • A number of "bands" and "lines" can be distinguished in the sarcomeres • I-band - actin filaments, • A-band - myosin filaments • H-band - zone of myosin filaments only • Z-line - zone of apposition of actin filaments belonging to two neighboring sarcomeres • M-line - band of connections between myosin filaments Contractile apparatus of skeletal muscle © Dr.N.Mugunthan 16

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19. Contraction & relaxation phases at the level of the sarcomere© Dr.N.Mugunthan 19

20. • Involuntary • Striated muscle • Ex: heart 2. Cardiac muscle © Dr.N.Mugunthan 20

21. Cardiac muscle • Myocytes contain one centrally placed nucleus. • Cardiac muscle exhibits cross-striations. (Less distinct) • Cardiac muscle cells often branch at acute angles • And are connected to each other by specializations of the cell membrane -intercalated discs. © Dr.N.Mugunthan 21

22. • Z-line of the myofibrils ("replaced" by the intercalated disc of the cell membrane). • Cardiac muscle becomes a 'functional synctium' to permit the spread of excitation. • Innervated by the autonomic nervous system Cardiac muscle cont.. © Dr.N.Mugunthan 22

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24. Cardiac muscle cont.. • Cardiac muscle does not contain satellite cells. • Cardiac muscle cannot regenerate. • Fibrosis occurs. © Dr.N.Mugunthan 24

25. 3. Smooth muscle • Smooth or plain muscle • Involuntary muscle • Non-striated muscle • Ex: hollow viscera, wall of respiratory tract & blood vessels © Dr.N.Mugunthan 25

26. Smooth muscle cont… • Consists of spindle shaped cells • Smooth muscle cells contain one centrally placed nucleus. • Innervation by the autonomic nervous system. (Involuntary muscle.) © Dr.N.Mugunthan 26

27. • In the cytoplasm, longitudinally oriented bundles of the myofilaments actin and myosin are seen. • Myofibrils do not run exactly longitudinally or parallel to each other • Striations, therefore not visible in smooth muscle. Smooth muscle cont… © Dr.N.Mugunthan 27

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29. Other contractile cells 1. Myoepithelial cells 2. Myofibroblasts 3. Pericytes © Dr.N.Mugunthan 29

30. • Hypertrophy • Hyperplasia • Regeneration • Atrophy / dystrophy Applied histology © Dr.N.Mugunthan 30

31. • During an asthma attack - smooth muscle contracts • In atherosclerosis - smooth muscle cells proliferate • Lactation - myoepithelial cells contracts & eject the milk • Myofibroblasts -found in cases of fibrosis Applied histology © Dr.N.Mugunthan 31

32. Practical aspects Skeletal muscle L.S • Longitudinal muscle fibers • Peripherally placed oval nuclei • Multiple nuclei in each cell (>100) • Transverse striations • Endomysium,perimy sium & epimysium © Dr.N.Mugunthan 32

33. Skeletal muscle T.S • Cross section of muscle fibers • Peripherally placed nuclei • Multiple nuclei • Transverse striations • Endomysium,perimy sium & epimysium Practical aspects © Dr.N.Mugunthan 33

34. Cardiac muscle L.S • Longitudinal muscle fibers • Branching and anastomosing fibres • Single centrally placed nuclei • Transverse striations (less distinct) • Intercalated disc Practical aspects © Dr.N.Mugunthan 34

35. 1. Skeletal muscle 2. Cardiac muscle 3. Smooth muscle Summary © Dr.N.Mugunthan 35

36. • Skeletal muscle L.S • Skeletal muscle T.S • Cardiac muscle L.S • Smooth muscle Summary © Dr.N.Mugunthan 36

37. • Skeletal muscle L.S • Skeletal muscle T.S • Cardiac muscle L.S • Smooth muscle Summary © Dr.N.Mugunthan 37

38. • Skeletal muscle L.S • Skeletal muscle T.S • Cardiac muscle L.S • Smooth muscle Summary © Dr.N.Mugunthan 38

39. • Skeletal muscle L.S • Skeletal muscle T.S • Cardiac muscle L.S • Smooth muscle Summary © Dr.N.Mugunthan 39

40. Exercise -1 © Dr.N.Mugunthan 40

41. Exercise -2 © Dr.N.Mugunthan 41

42. Exercise -3 © Dr.N.Mugunthan 42

43. © Dr.N.Mugunthan 43

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