http://www.med.muni.cz/histol/MedAtlas_2/img_1024x768/OH_img6-1.jpg Muscle tissue •Dept. Histology & Embryology •Faculty of Medicine MU • •pvanhara@med.muni.cz •Petr Vaňhara, PhD General characteristic of muscle tissue •Hallmarks §Unique cell architecture §Excitability and contraction §Mesodermal origin • •Muscle tissue §Skeletal §Cardiac §Smooth • image002 -Composition: muscle cells + connective tissue, blood vessels -Unique cell architecture – long multinuclear cells – muscle fibers (rhabdomyocytes) -Long axis of cells is oriented parallel with direction of contraction -Specific terminology: •cell membrane = sarcolemma •cytoplasm = sarcoplasm •sER = sarcoplasmic reticulum • •Muscle fiber – microscopic unit of skeletal muscle •Myofibril – LM unit – myofilaments – unit of muscle fibers •Myofilaments – filaments of actin and myosin (EM) • Histology of skeletal muscle tissue http://www.iupui.edu/~anatd502/Labs.f04/muscle%20lab/muscle%20CT%20coats%20schematic.jpg Connective tissue of skeletal muscle -Endomysium – around each muscle cell (fiber) -Perimysium – around and among the primary bundles of muscle cells -Epimysium – dense irregular collagen c.t., continuous with tendons and fascia -Fascia – dense regular collagen c.t. • http://faculty.etsu.edu/forsman/Histology%20of%20musclefor%20web_files/image011.jpg -Containment -Limit of expansion of the muscle -Transmission of muscular forces Connective tissue of skeletal muscle EM006b image1 EM007b Image285 Structure of skeletal muscle Svalová tkáň - 1 Kosterní svalovina musske skmusadi -morphological and functional unit: muscle fiber (rhabdomyocyte) – elongated, cylindrical-shaped, multinucleated cell (syncytium) -nuclei are located at the periphery (under sarcolemma) -myofibrils show cross striation -diameter of muscle fiber: 25-100 mm -length: millimeters - centimeters (up to 15) Structure of skeletal muscle •Muscle fiber = myofiber = syncitium = rhabdomyocyte •Muscle fiber – morphological and functional unit of skeletal muscle [Ø 25 – 100 mm] •Myofibrils – compartment of fiber sarcoplasm [Ø 0.5 – 1.5 mm] •Sarcomere – the smallest contractile unit [2.5 mm], serial arrangement in myofibrils •Myofilaments – actin and myosin, are organized into sarcomeres [Ø 8 and 15 nm] • Ultrastructure of rhabdomyocyte Muscle_Cell_Close-up_1 Sarcomere T-tubule terminal cisterna mitochondria myofibrils sarcolemma Ultrastructure of rhabdomyocyte Sarcolemme + t-tubules, Sarcoplasm: Nuclei, Mitochondria, Golgi apparatus, Glycogen (b granules) Sarcoplasmic reticulum (smooth ER) – reservoir of Ca2+ Myofibrils (parallel to the length of the muscle fiber) tubules + cisternae of sER Myofibrils -elongated structures [Ø 0.5 – 1.5 m] in sarcoplasm of muscle fiber oriented in parallel to the length of the fiber, MuscleSarcomere -Actin + myosin myofilaments -Sarcomere -Z-line -M-line and H-zone -I-band, A-band muscle3 myogeom http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%203%20R eview/09-03bc_skelemusfi_1.jpg Sarcomere Imag108 A–band I–band ½ I-band H-zone Sarcomere sarcomere-e Sarcomere Sarcoplasmic reticulum, t-tubule 179 019852403x Terminal cisterna T-tubule Terminal cisterna TRIAD T-tubules (“T” system ) are invaginations of sarcoplasm and bring action potential to terminal cisternae change permeability of membrane for Ca ions emmodel Sarcoplasmic reticulum, t-tubule https://s-media-cache-ak0.pinimg.com/736x/13/d8/fb/13d8fb80fa4169d09365bbbdec8c07a9.jpg Thin myofilaments •Fibrilar actin (F-actin), (Æ 7 nm, «1 mm) • • •Tropomyosin – thin double helix in groove of actin double helix, spans 7 monomers of G-actin •Troponin – complex of 3 globular proteins •TnT (Troponin T) – binds tropomyosin •TnC (Troponin C) – binds calcium •TnI (Troponin I) inhibits interaction between thick •and thin filaments Subversion of the actin cytoskeleton during viral infection external image TN1a.jpg http://163.178.103.176/Tema1G/Grupos1/GermanT1/GATP20/e2_files/7no5.gif Thick myofilaments •Myosin • -Large polypeptide, golf stick shape, (Æ 15 nm, «1,5 mm) -Bundles of myosin molecules form thick myofilament http://www.aps.uoguelph.ca/~swatland/HTML10234/LEC11/PS50.gif https://cyhsanatomy1.wikispaces.com/file/view/image005.jpg/49897235/image005.jpg http://jonlieffmd.com/wp-content/uploads/2013/09/1-s2.0-S109727650900505X-gr1.jpg http://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Sarcomere.svg/1350px-Sarcomere.svg.png http://www.uic.edu/classes/bios/bios100/summer2006/kinesin.jpg Contraction -Propagation of action potential (depolarization) via T-tubule (= invagination of sarcolemma) -Change of terminal cisternae permeability – releasing of Ca+ ions increases their concentration in sarcoplasm -Myosin binds actin - sarcomera then shortens by sliding movement – contraction -Relaxation: repolarization, decreasing of Ca2+ ions concentration, inactivation of binding sites of actin for myosin • Imag110 myosin actin 1.Impulse along motor neuron axon 2.Depolarization of presynpatic membrane (Na+ influx) 3.Synaptic vesicles fuse with presynaptic membrane 4.Acetylcholine exocyted to synaptic cleft 5.Acetylcholine diffuses over synaptic cleft 6.Acetylcholine binds to receptors in postsynaptic membrane 7.Depolarization of presynaptic membrane and sarcolemma (Na+ influx) 8.T-tubules depolarization 9.Depolarization of terminal cisternae of sER 10.Depolarization of complete sER 11.Release of CaII+ from sER to sarcoplasm 12.CaII+ binds TnC 13.Troponin complex changes configuration 14.TnI removed from actin-myosin binding sites 15.Globular parts of myosin bind to actin 16.ATPase in globular parts of myosin activated 17.Energy generated from ATP®ADP + Pi 18.Movement of globular parts of myosin 19.Actin myofilament drag to the center of sarcomere 20.Sarcomeres contract (H-zone, I-band shorten) 21.Myofibrils contracted 22.Muscle fiber contracted Contraction http://jessicaz.me.cmu.edu/molecular_data/NMJ_files/image002.jpg [USEMAP] http://highered.mheducation.com/sites/0072495855/student_view0/chapter10/animation__breakdown_of_at p_and_cross-bridge_movement_during_muscle_contraction.html http://www.embryology.ch/images/mimgmuskel/m2histogenese/musc_junction.jpg Neuromuscular junction http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%203%20R eview/neur-musc-junc.fig.9.8a.jpg http://www.chop.edu/sites/default/files/myasthenia-gravis-neuromuscular-junction-illustration-773x9 49.png Myasthenia gravis http://www.chop.edu/sites/default/files/myasthenia-gravis-neuromuscular-junction-illustration-773x9 49.png 1 2 3 4 Myelinated axons Neuromuscular junction Capillaries Muscle fiber nucleus https://classconnection.s3.amazonaws.com/456/flashcards/545456/png/costamere-141C2C681FD3C54184F.pn g Costameres •Structural components linking myofibrils to sarcolemma •Circumferential alignment • dystrophin-associated glycoprotein (DAG) complex •links internal cytoskelet to ECM •Integrity of muscle fiber http://www.nature.com/nrm/journal/v10/n4/images/nrm2634-f1.jpg Costameres https://upload.wikimedia.org/wikipedia/commons/5/52/Costamere_structure_in_mouse_quadriceps_-_journ al.pone.0002604.g003-cropped.png https://www.researchgate.net/profile/Anders_Nedergaard/publication/230894835/figure/fig6/AS:2028394 70153739@1425372106375/This-figure-shows-the-structure-of-the-costamere-and-known-molecular-interac tions-Below.png Costameres http://ajs.sagepub.com/content/33/5/745/F1.large.jpg http://www.nature.com/nrg/journal/v14/n6/images/nrg3460-f1.jpg Duchenne muscular dystrophy http://compbio.berkeley.edu/people/ed/rust/dys-gene.png http://neuromuscular.wustl.edu/pics/biopsy/dmd/dmdrevhe.jpg http://neuromuscular.wustl.edu/pics/biopsy/dmd/dmdrevdys2.jpg http://neuromuscular.wustl.edu/pics/biopsy/dmd/dystrophinwb.jpg Lane 1: Becker dystrophy; Dystrophin has reduced abundance but normal size. Lane 2: Becker dystrophy; Dystrophin has reduced size and abundance. Lane 3: Normal; Dystrophin has normal size and amount. Lane 4: Duchenne dystrophy; Almost no protein is present. http://neuromuscular.wustl.edu/pathol/dmdpath.htm http://www.humanillnesses.com/original/images/hdc_0001_0002_0_img0183.jpg Duchennoe muscular dystrophy https://kin450-neurophysiology.wikispaces.com/file/view/timeline-DMD-patient.png/478191732/462x258/ timeline-DMD-patient.png •made up of long branched fiber (cells) – cardiomyocytes, -cardiomyocytes are cylindrical cells, branched on one or both ends (Y, X shaped cells), -Sarcoplasm: single nucleus in the center of cell, striated myofibrils, numerous mitochondria, -cells are attached to one another by end-to-end junctions – intercalated discs. HISTOLOGY OF CARDIAC MUSCLE TISSUE chains of cardiomyocytes blood capillary with erythrocytes Intercalated disc 4 C) cardiac muscle; 5. E) striations, branched fibers, central nuclei cardiacmuscle heartmuscle1 image1 arm8 CARDIAC MUSCLE TISSUE COMPARED TO SKELETAL -no triads, but diads: 1 t-tubule + 1 cisterna -t-tubules around the sarcomeres at the Z lines rather than at the zone of overlap -sarcoplasmic reticulum via its tubules contact sarcolemma as well as the t-tubules -cardiac muscle cells are totally dependent on aerobic metabolism to obtain the energy -large numbers of mitochondria in sarcoplasm and abundant reserves of myoglobin (to store oxygen) -abundant glycogen and lipid inclusions http://esciencenews.com/files/images/20080622204300.jpg http://medicalpicturesinfo.com/wp-content/uploads/2011/08/Cardiac-muscle-2.jpg Intercalated disc -„scalariform“ shape of cell ends -fasciae adherentes (adhesion of cells) -Nexus (quick intercellular communication – transport of ions, electric impulses, information) Muscle7 https://s-media-cache-ak0.pinimg.com/originals/ab/8c/4a/ab8c4abe938a777282f58e1acef9a46a.jpg http://www.cheaplasereye.com/wp-content/uploads/2014/05/intercalated-discs-gap-junctions.png A) Cardiac muscle nexus fascia adherens Intercalated disc: pure2 Myofibril of cardiomyocyte •Actin + myosin myofilaments •Sarcomere •Z-line •M-line and H-zone •I-band, A-band •T-tubule + 1 cisterna = diad (around Z-line) MuscleL1 abdelaziz_html_m5d945a9f Purkinje fibers -are located in the inner layer of heart ventricle wall -are specialized cells fibers that conduct an electrical stimuli or impulses that enables the heart to contract in a coordinated fashion -numerous sodium ion channels and mitochondria, fewer myofibrils Image:Purkinje fibers.jpg gr84 http://www.austincc.edu/rfofi/NursingRvw/NursingPics/MusclePics/Picture33.jpg SMOOTH MUSCLE TISSUE SMOOTH MUSCLE TISSUE -spindle shaped cells (leiomyocytes) with myofilaments not arranged into myofibrils (no striation), 1 nucleus in the centre of the cell -myofilaments form bands throughout the cell -actin filaments attach to the sarcolemma by focal adhesions or to the dense bodies substituting Z-lines in sarcoplasm -sarcoplasmic reticulum forms only tubules, Ca ions are transported to the cell via pinocytic vesicles -zonulae occludentes and nexuses connect cells -calmodulin http://download.e-bookshelf.de/download/0000/6653/27/L-X-0000665327-0001397099.XHTML/images/c04uf00 1.jpg Caveolae Caveolae are equivalent to t-tubule and in their membrane ions channel are present to bring Ca needed fo Contraction. Caveolae are in contact with sarcoplasmic reticulum. image1 SMOOTH MUSCLE TISSUE http://synapses.clm.utexas.edu/atlas/3_7.gif SmoothMuscle Smooth Muscle + nexuses SMOOTH MUSCLE TISSUE image006 Leiomyocytes are arranged into layers in walls of hollow (usually tubular) organs B) Smooth muscle smooth4 Cross section Longitudinal section http://www.austincc.edu/rfofi/NursingRvw/NursingPics/MusclePics/Picture36.jpg http://www.austincc.edu/rfofi/NursingRvw/NursingPics/MusclePics/Picture37.jpg http://www.austincc.edu/rfofi/NursingRvw/NursingPics/MusclePics/Muscle_clip_image016.jpg Hallmark Skeletal muscle Cardiac muscle Smooth muscle Cells Thick, long, cylindrical, non-branched Branched, cylindrical Small, spindle-shaped Nuclei Abundant, peripherally 1-2, centrally 1, centrally Filaments ratio (thin:thick) 6:1 6:1 12:1 sER and myofibrils Regular sER around myofibrils Less regular sER, myofibrils less apparent Less regular sER, myofibrils not developed T tubules Between A-I band, triads Z lines, diads Not developed Motor end plate Present Not present Not present Motor regulation Voluntary control No voluntary control No voluntary control Other Bundles, c.t. Intercalated discs Caveoli, overlapping cells Summary http://cshperspectives.cshlp.org/content/4/2/a008342/F1.large.jpg Embryonic development Regeneration http://image.slidesharecdn.com/ch10muscletissue-140721070554-phpapp01/95/ch10-muscle-tissue-65-638. jpg?cb=1405944451 http://cshperspectives.cshlp.org/content/4/2/a008342/F3.large.jpg https://www.youtube.com/watch?v=b1WD564sjWw http://www.intechopen.com/source/html/18233/media/image3.jpeg •Thank you for attention •pvanhara@med.muni.cz mu •http://www.med.muni.cz/histology