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Muscle tissue

Muscle tissue. Dr. Károly Altdorfer. itc.semmelweis.hu. Classification of muscular tissue. Classical view. Histologically: s k eletal muscle Striated muscle striated muscles of viscera cardiac muscle (heart) Smooth muscle – non striated (viscera and blood vessels).

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Muscle tissue

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  1. Muscle tissue Dr. Károly Altdorfer

  2. itc.semmelweis.hu

  3. Classification of muscular tissue Classical view Histologically: skeletal muscle Striated muscle striated muscles of viscera cardiac muscle (heart) Smooth muscle – non striated (viscera and blood vessels) Specialized cells whose primary role is contraction -- principal components - contractile proteins : actin and myosin

  4. Musceltissue smooth skeletal cardiac Histol. unit: cell fiber cell nucleus: central periph. central LS: CS:

  5. Skeletal muscle longitudinal section transverse section Cohnheim-fields Chicago blue or iron hematoxylin

  6. Skeletal muscle fiber d: 10 - 50 μm l: 2 mm-40 cm long, multinucleated cell = muscle fiber cross striation cytoplasm = sarcoplasm sarcolemma

  7. Organization of skeletal muscle Endomysium: loose connective tissue around each muscle fiber (basal lamina, reticular fibers, fibroblast) containing capillaries Perimysium: connective tissue (elastic and collagen fibers) around each fascicle (bundles of muscle fibers) and route for larger blood vessels Epimysium: external sheath of dense connective tissue surrounding the entire muscle

  8. Myofibrills, myofilaments (thick filaments) (thin filaments)

  9. Sarcomere A: anisotropic I: isotropic Sarcomere: Z I A H M H A I Z

  10. Actin and myosin

  11. Muscle contraction

  12. Sliding filament model of muscle contraction Molecular mechanism

  13. Sarcoplasmic reticulum Sarcoplasmic reticulum – specialized endoplasmic reticulum (calcium store, metabolisms) T tubular system-invagination of the sarcolemma at the border of A-I bands.

  14. Impulse propagation within the muscle

  15. Innervation - motor unit Motor unit: motorneuron (spinal cord or brainstem) and the innervated muscle fibers. The contraction is voluntary.

  16. Motor end plate light microscopy electronmicroscopy Ach and Ach-esterase!

  17. Myasthenia gravis

  18. Muscle spindles (stretch receptors)

  19. Muscle fiber types I Type I – red - slow oxidative fiber (many mitochondria and myoglobin, oxidative phosphorylation of fatty acid, slow, continuous contractions over prolonged periods, posture) Type IIa – fast intermediate oxidative-glycolytic fiber (mitochondria, myoglobin and glycogen, oxidative metabolism and anaerobic glycolysis, rapid contractions, athletics) Type IIb – white – fast glycolytic fibers (fewer mitochondria and myoglobin but abundant glycogen, glycolysis, rapid contraction but fatigue quickly, eye muscles, digits)

  20. Cardiac muscle longitudinal section cross section

  21. Cardiac muscle cells ID • branching cells • Cross striated (thick and thin filaments attached to Z discs) • lipofuchsin • Intercalated discs/ Eberth lines: end to end junctions between individual cardiac muscle cells ANF: Atrial natriuretic factor: wall of right atrium

  22. Intercalated disc - Eberth line Fascia adherens

  23. LS, CS

  24. (Eberth-lines)

  25. Purkinje-fibers(mod. cardiac muscle cells: glycogen + myofibrils)

  26. Skeletal muscle T-tubuli, triads Cardiac muscle: T-tubuli and diads ER: SR ER: SR T-tubulus Btw. A- and I-lines T-tubulus at the level of Z-line Röhlich

  27. Smooth muscle longitudinal section -cross section

  28. Smooth muscle cell 20 μm (small blood vessel)-500 μm (pregnant uterus) Nucleus is located centrally Contractile elements-myofilaments (not arranged in the ordered manner) Sarcoplasmic reticulum is present but no T systems

  29. Spontaneous rhytmic contractions Pacemaker cells  gap junction Autonomic nerves (groundplexus) + hormons: modify activity Subsarcolemmal plaques; „dense bodies”: aktin anchoring places

  30. Ultrastructure of smooth muscle cell (desmin, vimentin) (myosin) (actin) (functionally similar to Z discs)

  31. Ductus deferens, m. sphincter pupillae: fine, accurate innervation and activity Gut tube: peristaltic movements (slow)

  32. Locations of smooth muscle tissue Uterus Medium arteries and arterioles Intestines Esophagus Skin

  33. Smooth muscle and myenteric plexus (Auerbach)

  34. vas deferens + artery

  35. Peristalsis of the stomach endoscopic view of the stomach

  36. Other contractile cells Cells that have contractile properties and contain myofilaments. Myofibroblast (cells of connective tissue) Myoepithel cells - sweat glands, mammary glands, salivary glands, iris - (components of the epithelial tissue)

  37. Images: • Dr. Zita Puskár • Prof. Dr. Röhlich: Szövettan

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