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