muscle tissue
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MUSCLE TISSUE
MUSCLE TISSUE
// AGGREGATES OF SPECIALIZED ELONGATED CELLS, PRIMARY FUNCTION IS CONTRACTION
INTERACTION OF MYOFILAMENTS
CLASSIFICATION
STRIATEDSKELETALVISCERAL STRIATEDCARDIAC
SMOOTH
SKELETL MUSCLE
MUSCLE FIBERS/CELLS MESENCHYMAL, FUSION OF
MYOBLAST SIZE VARIABLE ENDOMYSIUM PERIMYSIUM, FASICLES EPIMYSIUM
MUSCLE FIBER LONGITUDINAL MULTINUCLEATED CROSS STRIATIONS TRANS. SECTION
POLYGGNOL WITH FLAT NUCLEI
10—100 micrometer
MUSCLE FIBER
SARCOLEMMA SARCOPLASM MYOFIBRILS MYOFILAMENTS SARCOPLASMIC REITCULUM
MYOFIBRILS
LONGITUDINALLY ARRANGED SUBUNITS WITHIN A FIBER
COMPOSED OF BUNDLES OF MYOFILAMENTS
ACTUAL CONTRACTILE ELEMENTS ARRANGMENT CROSS STRIATIONS SARCOMERE
CROSS STRIATIONS STAINED UNSTAINED
PREPARATIONS A BAND( DARK) I BAND
( LIGHT) A BAND MYOSIN
FILAMENT BIREFRINGENT
ANISOTROPICCENTER OF SARCOMERE
H ZONE & M LINE I BAND ACTIN FILAMENT
MONOREFRINGENT & ISOTROPICADJACENT SARCOMEREZ LINE
THIN FILAMENT F ACTIN TROPOMYOSIN &
TROPONIN F ACTIN double stranded
polarized helix, polymers of G ACTIN
Anchored to Z line alpha actinin
I band, edges A band TROPOMYOSIN double helix,
grooves,mask binding sites TROPONIN 3 subunits TnC___Ca
TnT___troponin to tropomyosin TnI___actin
Z LINE
ZIG ZAG FILAMENTOUS +Z MATRIX ANCHORS THIN FILAMENTS OF
ADJACENT SARCOMERE THRU ALPHA ACTININ
THICK FILAMENTS MYOSIN II A BAND 2 HEAVY & 2PAIRS OF LIGHT CHAINS HEAVY MYOSIN rod like part with globular heads LIGHT CHAIN heads BINDING SITES ATP & ACTIN HEADS FORM CROSS BRIDGES b/w THICK &
THIN H ZONE NARROW CENTRAL REGION WITHOUT
HEADS ACESSORY PROTEINS
SARCOPLASMIC RETICULUM
SER AI------AI BAND TERMINAL CISTERN Gated Ca
channel T TUBULES voltage sensor protein TRIAD MITOCHONDRIA & GLYCOGEN
GRANULES
Muscle contraction
SARCOMERE SHORTENS > OVERLAP b/w THICK & THIN
FILAMENTS A BAND REMAINS SAME IBAND SHORTENS
CONTRACTION
ATTACHMENT RELEASE BENDING FORCE GENERATION RE ATTACHMENT
MUSCLE FIBERS
RED, WHITE & INTERMEDIATE MYOGLOBIN OXYGEN BINDING
PROTEIN MITOCHONDRIA CYTOCHROMES
ELECTRON TRANSPORT COMPLEXES
RED WHITE SMALL SLOW TWITCH > MYOGLOBIN &
MITOCHONDRIA RESISTANT TO
FATIGUE SLOW CONTRACTION < NEUROMUSCULAR
JUNCTIIONS LONG MUSCLES OF
BACK
LARGE FAST TWITCH < MYOGLOBIN &
MITOCHONDRIA FATIGUE RAPIDLY RAPID CONTRACTION > NEUROMUSCULAR
JUNCTIIONS EXTRAOCULAR &
DIGITAL
CARDIAC MUSCLE
LIGHT MICROSCOPE BRANCHING SYNCITIUM 10—14 micrometer 100 micrometer long ENDOMYSIUM less well organized,
PERIMYSIUM SARCOLEMMA NUCLEUS single central SARCOPLASM perinuclear INTERCALATED DISC
ELECTRON MICROSCOPE
MYOFIBRILS not well demarcated SARCOPLASM
Abundunt mitochondriaSarcoplasmic reticulumFat droplets GlycogenLipofuscin pigment granules
SARCOPLASMIC RETICULUM
CISTERNS narrower with frequent anastomosis
T tubules are wider, external lamina
T tubules at the level of Z band No dilated terminal cistern DIAD
INTERCALATED DISC L/M Cross bands
0.5—1 micrometer
Specialized areas of cell junction
Step wise Zonula adherens,
desmosomes, gap junction
SMOOTH MUSCLE SPINDLE SHAPED CELLS, SMALLER // TO EACH OTHER (close packing & efficient
transfer of force) BASAL LAMINA, RETICULAR LAMINA DIAMETER LENGTH 20-500 micrmeter SINGLE CENTRAL NUCLEUS,(COCK SCREW) TRAN. Sect.
ELCTRON MICRSCOPEBASAL LAMINA, RETICULAR LAMINA Complete covering( nexus)
PLASMA MEMBRANEalternnate areas of a) dense submembrane patches
b) uncoated regions
GAP JUNCTIONS BLOOD SUPPLY LESS EXTENSIVE
SARCOPLASM
ORGANELLES at each end of nucleus
RUDIMENTRY S.E.R NO T TUBULES TWO CYTOPLASMIC DOMAINS CYTOSKELETON & CONTRACTILE
APPARATUS
CYTOSKELETAL DOMAIN
LONGITUDINAL BUNDLES OF INTERMEDIATE & THIN FILAMENTS ASSOCIATED WITH DENSE BODIES
DENSE BODIES alpha actinin
Contractile domain THIN & THICK FILAMENTS 1:15 THICK FILAMENTS ARE LABILE OBLIQUE TO CYTOSKELETON SUB MEMEBRANOUS DENSE BODIES TRANSMEMBRANE PROTEINS FBRONECTIN & LAMININ DISTRIBUTION & TRANSMISSION OF FORCE
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