Muscle. Undergraduate Graduate Histology Lecture Series

Transcription

1 Muscle Undergraduate Graduate Histology Lecture Series Larry Johnson, Professor Veterinary Integrative Biosciences Texas A&M University College Station, TX 77843

2 Muscle Introduction Contractivity is one of the fundamental properties of protoplasm and is exhibited in varying degree by nearly all cell types. In the cells of muscle, the ability to convert chemical energy into mechanical work has become highly developed. Locomotion of multicellular animals, beating of their hearts, and movement of their internal organs depends on muscles of different types. Cardiac muscle Smooth muscle Skeletal muscle

3 Objectives Identify smooth, skeletal, and cardiac muscle on route histological preparations Explain the morphological basis for the different functions of these three types of muscle Distinguish between the modes of excitation of these three types of muscle

4 Four basic types of tissues Epithelium (90% of tumors) Connective tissue Muscular tissue Nervous tissue

5 Muscle Function: Generation of contractile force Distinguishing features: high concentration of contractile proteins actin and myosin arranged either diffusely in the cytoplasm (smooth muscle) or in regular repeating units called sarcomeres (striated muscles, e.g., cardiac and skeletal muscles) Cardiac muscle Smooth muscle Striated muscles

6 Muscle - Histological identification Skeletal muscle very long cylindrical striated muscle cells with multiple peripheral nuclei Dilator muscle of iris Myoepithelial cells Cardiac muscle short branching striated muscle cells with centrally located nuclei Smooth muscle closely packed spindle-shaped cells with a single centrally placed nucleus and cytoplasm that appears homogeneous by light microscopy

7 Muscle Distribution: Skeletal striated muscles mostly associated with the skeleton

8 Muscle Distribution: Cardiac striated muscles associated with the heart large artery of lung

9 Muscle Distribution: Smooth fusiform cells associated with the viscera, respiratory tract, blood vessels, uterus, etc. Ureter Ductus deferens Smooth muscle

10 Types of muscle Skeletal muscle Voluntary, large and multinucleated cells, striated Cardiac muscle Involuntary, mononucleated and branched cells, striated Smooth muscle Involuntary, mononucleated, non-striated

11 Connective tissue layers of skeletal muscle Epimysium - coarse CT Perimysium - less coarse CT Endomysium - delicate CT Perimysium Epimysium Endomysium

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13 Tongue, monkey Skeletal muscle nuclei Fasciculi Endomysium Muscle cells skeletal muscle nuclei, Connective tissue of perimysium striations

14 Connective Tissue connects cells (muscle fibers) of skeletal muscle Endomysium

15 Connective Tissue Layers of PERIMYSIUM Skeletal Muscle ENDOMYSIUM

16 Connective Tissue Layers of Skeletal Muscle Endomysium Individual cell

17 Striated Muscle Skeletal Cardiac A I A Band = dark band Anisotropic = does alter polarized light (Birefringent) I Band = light band Isotropic = does not alter polarized light A I

18 A I Polarized Light Micrograph Of Human High-Res Stock Photography...

19 Striated Muscle (Skeletal) Repeating A and I bands alone the cell s length creates repeating sarcomeres A I A I A I A I

20 Striated Muscle (skeletal) A I Sarcomeres are organized for rapid and highly controlled contraction

21 Striated Muscle (Skeletal) Sarcomere = structural unit and functional unit of striated muscle

22 Striated Muscle (Skeletal)

23 Thin filament = actin + actin-associated proteins Actin-associated proteins dictate network or bundle creating the Z line Striated Muscle Thick filament = myosin

24 Striated Muscle Note uniform spacing of troponin

25 Striated Muscle

26 Unexplained complexity in skeletal muscle 13 isoforms of myosin 128 isoforms of troponin

27 Footprints of evolution fossils comparative anatomy, morphology and physiology biological macromolecules nucleic acids & proteins document evolutionary history provide insights into evolution of form and function life biomolecules e.g., cytochrome c in rice & tuna Slides adapted from Dr. Chris Collet Queensland University of Technology Australia

28 Based on scientific research, what three characteristics do these mammals all have in common

29 2. Mammary with these mammals? glands 1. Hair 3.Special inner ear bones

30 Ear bones of mammals (including human) began as reptile jaws This 125-million year old fossil has inner-ear anatomy intermediate (still attached to the jaw) between reptiles and mammals. In the early embryonic stage of modern mammals, the middle ear was still attached to the jaw.

31 Footprints of evolution fossils comparative anatomy, morphology and physiology biological macromolecules nucleic acids & proteins document evolutionary history provide insights into evolution of form and function life biomolecules e.g., cytochrome c in rice & tuna Slides adapted from Dr. Chris Collet Queensland University of Technology Australia

32 You can learn a lot about humans from studying animals

33 Footprints of evolution fossils comparative anatomy, morphology and physiology biological macromolecules nucleic acids & proteins document evolutionary history provide insights into evolution of form and function life biomolecules e.g., cytochrome c in rice & tuna Slides adapted from Dr. Chris Collet Queensland University of Technology Australia

34 Introduction: Pathways Of Protein Evolution Protein Evolutionary Trees

35 Introduction: Pathways Of Protein Evolution Point mutation change of function to meet changing requirements Duplication simplest mechanism of evolving new proteins functional divergence of duplicates to meet new requirements in biochemical pathways Exon shuffling creating novel proteins for new pathways of development Alternate splicing protein diversity from existing genes

36 Exon Shuffling And Mosaic Proteins If structural = functional modules then modules (domains) can be moved around genome fulfill new functions proteins show a mosaic history

37 Exon Shuffling and Mosaic Proteins Many proteins are modular units derived from many sources

38 Alternate Pathways Of Transcript Splicing Different exons may be joined to produce a related set of mrnas encoding a small family of related proteins protein isoforms Splicing patterns often tissue-specific Related proteins may perform similar, not necessarily identical, functions in different types of cells Splicing is the norm in elks as a means of producing diversity

39 Unexplained complexity in skeletal muscle 13 isoforms of myosin 128 isoforms of troponin

40 Cell Structure of Skeletal Muscle Myofiber = multinucleated cell Myofibrils Sarcomere Z Line (α-actinin) I Band (actin, tropomyosin, troponins) A Band (myosin, overlaps actin) H Band (myosin with no overlap of actin) H

41 Cell Structure of Skeletal Muscle Individual cells Individual cell

42 Cell Structure of Skeletal Muscle

43 Cell Structure of Skeletal Muscle

44 Skeletal Muscle Wall Paper

45 Skeletal Muscle Sarcomeres shorten to create contraction

46 Skeletal Muscle

47 Remember the Intermediate Filaments on Epithelium Structural support of epithelial desmosomes and hemidesmosomes

48 Intermediate Filaments Function in Muscle Cells Myofibril organization Muscle cells Cell =

49 Contraction of the Sarcomere Thin Filament Actin (F-actin) Tropomyosin Troponin T - attaches to tropomyosin C - binds calcium ions I - inhibits actin-myosin interaction Thick Filament (myosin) Sliding filament theory of contraction

50 Sliding filament theory of contraction of the sarcomere Contraction (know five steps) 1. Troponin-C binds calcium 2. Troponin changes shape causing conformational change in tropomyosin exposing actin binding site 3. Myosin binds actin and released inorganic phosphate inducing 4. Movement of myosin head (motor, power stroke ) and sliding of actin filament in relation to the myosin filament 5. ATP ADP and inorganic phosphate binds to myosin head cocking it

51 Contraction of the sarcomere

52 Contraction of the sarcomere

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54 Calcium Regulation Transverse (T) tubule (invagination of sarcolemma) transmit depolarization of membrane deep into the cell Sarcoplasmic reticulum (SER of cell) release Ca ++ for contraction then recovers Ca ++ after contraction Triad = (T tubule and two ends of SER)

55 Calcium Regulation TRANVERSE (T) TUBULE TRIAD = (T TUBULE + TWO ENDS OF SER)

56 Calcium Regulation Transverse Tubule

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58 Stimulation of Muscle Cells

59 Innervation of Skeletal Muscle Motor end-plate: Synaptic cleft Acetylcholine and receptor Junctional Folds

60 Innervation of Muscle

61 Slide HISTO007 skeletal muscle cells Nerve muscle interface at the motor end plates Note the motor end plates in several skeletal muscle cells

62 Innervation of Muscle

63 Innervation of Muscle

64 Innervation of Muscle

65 Innervation of Muscle

66 Innervation of Muscle

67 Innervation of Muscle

68 Sensory Innervation of Muscle Muscle Fiber / Cell Muscle Spindle

69 Innervation of Muscle Muscle Spindle Muscle Spindle Intracapsular fibers

70 Tongue Muscle spindle capillaries Muscle spindles Intrafusal fibers inside the capsule fibroblasts nerve

71 Types of Fibers in Skeletal Muscle Red (Slow, Oxidative) High Myoglobin High Cytochromes/ Mitochondria Posture, flight muscle in birds

72 Types of Fibers in Skeletal Muscle White (Fast, Glycolytic) Low Myoglobin Fewer Mitochondria

73 Types of Fibers in Skeletal Muscle Intermediate (Fast, Oxidative, and Glycolytic)

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75 elated

76 Cardiac Muscle

77 Cardiac Muscle is Striated Muscle Differences From Skeletal Muscle Mononucleated vs. Multinucleated Central vs. Peripheral Nuclei Diad vs. Triad

78 Cardiac Muscle is Striated Muscle Intercalated Disc Fascia Adherens Maculae Adherens Gap Junctions - Lateral Portion

79 Cardiac Muscle Intercalated Disc

80 Intercalated Disc Fascia Adherens Maculae Adherens Gap Junctions Lateral Portion Cardiac Muscle Intercalated discs

81 Intercalated Disc

82 Cardiac Muscle is Striated Muscle

83 Cardiac Muscle

84 Cardiac Muscle Diad located at Z line Diad = (T tubule + one end of SER)

85 Cardiac Muscle

86 Cardiac Muscle

87 Cardiac Muscle has Organized Contractions PURKINJE FIBERS

88 Heart Internodal connections

89 Cardiac Muscle has Organized Contractions Purkinje Fibers

90 Cardiac Muscle Purkinje Fibers

91 Cardiac Muscle Purkinje Fibers Nexus (gap junction)

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93 Smooth Muscle Cell organization Myofilament organization Intermediate filaments and fusiform dense regions

94 Smooth Muscle

95 Smooth Muscle MUSCULAR ARTERY

96 Smooth Muscle Arrector Pili Muscle in Skin

97 Smooth Muscle Has a PAS + basement membrane

98 Smooth Muscle Actin Myosin

99 Smooth Muscle Intracellular caveolae

100 Smooth Muscle

101 Smooth Muscle

102 Smooth Muscle

103 Regeneration of Muscle Cardiac None Skeletal Some Smooth - Lots

104 Muscle Striated - Smooth

105 Summary of Muscle shapes and excitations of types

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107 Many illustrations in these VIBS Histology YouTube videos were modified from the following books and sources: Many thanks to original sources! Bruce Alberts, et al Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY. Bruce Alberts, et al Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY. William J. Banks, Applied Veterinary Histology. Williams and Wilkins, Los Angeles, CA. Hans Elias, et al Histology and Human Microanatomy. John Wiley and Sons, New York, NY. Don W. Fawcett Bloom and Fawcett. A textbook of histology. W. B. Saunders Company, Philadelphia, PA. Don W. Fawcett Bloom and Fawcett. A textbook of histology. Chapman and Hall, New York, NY. Arthur W. Ham and David H. Cormack Histology. J. S. Lippincott Company, Philadelphia, PA. Luis C. Junqueira, et al Basic Histology. Lange Medical Publications, Los Altos, CA. L. Carlos Junqueira, et al Basic Histology. Appleton and Lange, Norwalk, CT. L.L. Langley, et al Dynamic Anatomy and Physiology. McGraw-Hill Book Company, New York, NY. W.W. Tuttle and Byron A. Schottelius Textbook of Physiology. The C. V. Mosby Company, St. Louis, MO. Leon Weiss Histology Cell and Tissue Biology. Elsevier Biomedical, New York, NY. Leon Weiss and Roy O. Greep Histology. McGraw-Hill Book Company, New York, NY. Nature ( Vol. 414:88,2001. A.L. Mescher 2013 Junqueira s Basis Histology text and atlas, 13 th ed. McGraw Internet images and videos on biological presentations

108 Next time Peripheral Nervous System

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