Medical School Histology Basics Muscle

1. Medical School Histology Basics Muscle VIBS 289 lab Larry Johnson Texas A&M University

2. MUSCLE Function and Features Function: • Generation of contractile force • Locomotion of multicellular animals, beating of their hearts, and movement of their internal organs depends on muscles of different types. 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) • All three muscle types comes from mesoderm

3. 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

5. Smooth muscle no striations

6. Ureter (Slide 262 smooth muscle) Connective tissue Transitional epithelium Connective tissue Smooth muscle fibers are long, spindle-shaped cells shown here as bundles of cells

7. Smooth muscle and psudostratified columnar epithelium in ductus deferens (toluidine blue) Slide 19678 Smooth muscle cells

8. Slide 32409: Rat intestine (toluidine blue) Central lacteal epithelium Gut lumen Muscularis externa smooth muscle,

9. Smooth muscle, muscularis externa, muscularis mucosa, Auerbach’s plexus, Slide 32409: Rat intestine (toluidine blue) vein epithelium lacteal Auerbach’s plexus Smooth muscle, muscularis externa, muscularis mucosa, Meissner’s plexus

10. Duodenum (Slide 152) Smooth muscle longitudinal profiles sarcoplasm in these cells have no regular cross striations Transverse profiles of smooth muscle cells longitudinal and transverse profiles of smooth muscle cells

11. 243 PAS staining of smooth muscle cell basement membrane in the stomach Smooth muscle cell nuclei

12. Smooth muscle; EM 9 of smooth muscle cells, note organelles • Nucleus of smooth muscle cell • Secondary lysosome • Mitochondrion

13. 10 f EM 10f: Arteriolar wall; 30,000x • Apical caveolae • Collagen • Dense bodies • Elastic fiber • Endothelial cell • Nuclear pore • RER

14. Smooth muscle; EM 10e of smooth muscle cell. Note nerve attachment • Smooth muscle cell • Collagen • Nerve ending • Mitochondrion

15. Individual cells

16. Slide 136: Tongue, monkey Connective tissue of the perimysium capillaries nerve Skeletal muscle cells Perimysium

17. Slide HISTO007: Skeletal muscle – nerve and motor end plates Motor end plates in skeletal muscle One nerve innervates several muscle cells Histo 07 Skeletal muscle cells Slide HISTO007: Skeletal muscle motor end plates

18. Slide 136 SKELETAL MUSCLE Slide 136: Tongue, monkey Anisotropic to polarized light =“A” band = dark band Isotropic to polarized light = “I” band = light band A band I band A band I band

20. Slide 136: Tongue, monkey Skeletal muscle nucleiFasciculi Endomysium Muscle cells skeletal muscle nuclei, Connective tissue of striations perimysium

21. Slide 136: Tongue, monkey Capillaries in skeletal muscle endomysium

22. 211 211 -001 Skeletal muscle Striations = A&I bands skeletal muscle cell nuclei,

23. Cross striations in skeletal muscle cells (Slide 211-001) 211 Skeletal muscle cells A band Z disc I band

24. EM 10; skeletal muscle; 30,000x • Mitochondria • Sarcoplasmic reticulum • Terminal cisternae

25. 137 Esophagus – skeletal and smooth muscle Connective tissue nerve

26. Contracted skeletal muscle cells have small I bands EM 10a: Endothelial cells lining capillary with pericyte in the vessel wall; 20,000x • Lumen • Endothelial cell • Tight junction

27. Nerve – muscle interface at the motor end plates Muscle spindles stretch receptors Muscle fibers inside a connective tissue capsule

28. Slide HISTO007 skeletal muscle cells Nerve – muscle interface at the motor end plates Note the motor end plates in several skeletal muscle cells

29. 19753 Muscle spindles Muscle spindle #19753 Intrafusal fibers inside the capsule

30. 136 Tongue Muscle spindle Intrafusal fibers inside the capsule Muscle spindles capillaries nerve fibroblasts

31. Skeletal muscle cells Cardiac muscle cells Intercalated disc = cell attachments 225 211

32. EM 10b

33. 225 Intercalated disc in cardiac cells of the Heart, epicardium I band A band

35. Slide 226 Cardiac muscle cells are striated Cardiac muscle cells are branched Cardiac cells are separated at the intercalated discs revealing the shape of individual cells, that the cells are branched, and the nuclei are in the center of cells.

36. Slide 226 Cardiac muscle cells are striated Cardiac muscle cells Cardiac cells can accumulate a high density of lipofuscin granules resulting from incomplete lysosomal digestion within the cell

37. Heart Internodal connections

38. Histo0 23 heart muscle Cardiac muscle cells Purkinje fibers

39. EM 10b cardiac muscle cells Intercalated discs

40. EM 10b Gap junctions Intercalated discs

41. Skeletal muscle – triad located at A-I junction CARDIAC MUSCLE –Diad located at Z disc TRIAD = (T TUBULE + TWO ENDS OF SER) Diad = (T tubule + one end of SER)

42. EM 10 EM 10b Skeletal muscle cell triad Cardiac muscle cell diad

43. Test Questions on Muscle Which is (are) true about striated muscle? • The “A” band = dark band = anisotropic to polarized light • The “I” band = light band = isotropic to polarized light • The endomysium is delicate connective tissue around individual myofibrils • a & b • a, b, & c Which types of muscle have nuclei in the center of its cells and are involuntary: • Smooth muscle • Cardiac muscle • Skeletal muscle • a and b • a, b and c Which is/are related to stimulation of muscle contraction: • Motor end plate • Gap junctions • Purkinje fibers • a and b • a, b and c

44. In summary

45. 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. 1983. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY. • Bruce Alberts, et al. 1994. Molecular Biology of the Cell. Garland Publishing, Inc., New York, NY. • William J. Banks, 1981. Applied Veterinary Histology. Williams and Wilkins, Los Angeles, CA. • Hans Elias, et al. 1978. Histology and Human Microanatomy. John Wiley and Sons, New York, NY. • Don W. Fawcett. 1986. Bloom and Fawcett. A textbook of histology. W. B. Saunders Company, Philadelphia, PA. • Don W. Fawcett. 1994. Bloom and Fawcett. A textbook of histology. Chapman and Hall, New York, NY. • Arthur W. Ham and David H. Cormack. 1979. Histology. J. S. Lippincott Company, Philadelphia, PA. • Luis C. Junqueira, et al. 1983. Basic Histology. Lange Medical Publications, Los Altos, CA. • L. Carlos Junqueira, et al. 1995. Basic Histology. Appleton and Lange, Norwalk, CT. • L.L. Langley, et al. 1974. Dynamic Anatomy and Physiology. McGraw-Hill Book Company, New York, NY. • W.W. Tuttle and Byron A. Schottelius. 1969. Textbook of Physiology. The C. V. Mosby Company, St. Louis, MO. • Leon Weiss. 1977. Histology Cell and Tissue Biology. Elsevier Biomedical, New York, NY. • Leon Weiss and Roy O. Greep. 1977. Histology. McGraw-Hill Book Company, New York, NY. • Nature (http://www.nature.com), Vol. 414:88,2001. • Arthur C. Guyton,1971.Textbook of Medical Physiology W.B. Saunders company, Philadelphia, PA • WW Tuttle and BA Schottelius 1969 Textbook of Physiology C.V. Mosby Co. • A.L. Mescher 2013 Junqueira’s Basis Histology text and atlas, 13th ed. McGraw

46. Big Bend National Park, TX

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