Histology Notes

1. MUSCLE TISSUE

2. MUSCLE TISSUE
 // AGGREGATES OF SPECIALIZED
ELONGATED CELLS, PRIMARY
FUNCTION IS CONTRACTION
 INTERACTION OF MYOFILAMENTS

3. CLASSIFICATION
 STRIATED
SKELETAL
VISCERAL STRIATED
CARDIAC
 SMOOTH

4. SKELETL MUSCLE
 MUSCLE FIBERS/CELLS
 MESENCHYMAL, FUSION OF MYOBLAST
 SIZE VARIABLE
 ENDOMYSIUM
 PERIMYSIUM, FASICLES
 EPIMYSIUM

5. MUSCLE FIBER
 LONGITUDINAL
 MULTINUCLEATED
 CROSS STRIATIONS
 TRANS. SECTION
POLYGGNOL WITH
FLAT NUCLEI
 10—100 micrometer

6. MUSCLE FIBER
 SARCOLEMMA
 SARCOPLASM
 MYOFIBRILS MYOFILAMENTS
 SARCOPLASMIC REITCULUM

9. MYOFIBRILS
 LONGITUDINALLY ARRANGED
SUBUNITS WITHIN A FIBER
 COMPOSED OF BUNDLES OF
MYOFILAMENTS
 ACTUAL CONTRACTILE ELEMENTS
 ARRANGMENT CROSS STRIATIONS
 SARCOMERE

10. CROSS STRIATIONS
 STAINED UNSTAINED
PREPARATIONS
 A BAND( DARK) I BAND
( LIGHT)
 A BAND MYOSIN FILAMENT
BIREFRINGENT
ANISOTROPIC
CENTER OF SARCOMERE
H ZONE & M LINE
 I BAND ACTIN FILAMENT
MONOREFRINGENT &
ISOTROPIC
ADJACENT SARCOMERE
Z LINE

11. 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

12. Z LINE
 ZIG ZAG
 FILAMENTOUS +Z MATRIX
 ANCHORS THIN FILAMENTS OF
ADJACENT SARCOMERE THRU ALPHA
ACTININ

13. 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

15. SARCOPLASMIC RETICULUM
 SER
 AI------AI BAND
 TERMINAL CISTERN Gated Ca channel
 T TUBULES voltage sensor protein
 TRIAD
 MITOCHONDRIA & GLYCOGEN
GRANULES

17. Muscle contraction
 SARCOMERE SHORTENS
 > OVERLAP b/w THICK & THIN
FILAMENTS
 A BAND REMAINS SAME
 IBAND SHORTENS

18. CONTRACTION
 ATTACHMENT
 RELEASE
 BENDING
 FORCE GENERATION
 RE ATTACHMENT

22. MUSCLE FIBERS
 RED, WHITE & INTERMEDIATE
 MYOGLOBIN OXYGEN BINDING
PROTEIN
 MITOCHONDRIA CYTOCHROMES
ELECTRON TRANSPORT
COMPLEXES

23. RED WHITE
 SMALL  LARGE
 SLOW TWITCH  FAST TWITCH
 > MYOGLOBIN &  < MYOGLOBIN &
MITOCHONDRIA MITOCHONDRIA
 RESISTANT TO  FATIGUE RAPIDLY
FATIGUE  RAPID CONTRACTION
 SLOW CONTRACTION  > NEUROMUSCULAR
 < NEUROMUSCULAR JUNCTIIONS
JUNCTIIONS  EXTRAOCULAR &
 LONG MUSCLES OF DIGITAL
BACK

24. CARDIAC MUSCLE

26. LIGHT MICROSCOPE
 BRANCHING SYNCITIUM
 10—14 micrometer
 100 micrometer long
 ENDOMYSIUM less well organized,
PERIMYSIUM
 SARCOLEMMA
 NUCLEUS single central
 SARCOPLASM perinuclear
 INTERCALATED DISC

28. ELECTRON MICROSCOPE
 MYOFIBRILS not well demarcated
 SARCOPLASM
Abundunt mitochondria
Sarcoplasmic reticulum
Fat droplets
Glycogen
Lipofuscin pigment granules

29. 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

31. INTERCALATED DISC
 L/M Cross bands 0.5
—1 micrometer
 Specialized areas of
cell junction
 Step wise
 Zonula adherens,
desmosomes, gap
junction

32. 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.

34. ELCTRON MICRSCOPE
BASAL LAMINA, RETICULAR LAMINA
Complete covering( nexus)
 PLASMA MEMBRANE
alternnate areas of a) dense submembrane patches
b) uncoated regions
 GAP JUNCTIONS
 BLOOD SUPPLY LESS EXTENSIVE

35. SARCOPLASM
 ORGANELLES at each end of nucleus
 RUDIMENTRY S.E.R
 NO T TUBULES
 TWO CYTOPLASMIC DOMAINS
 CYTOSKELETON & CONTRACTILE
APPARATUS

36. CYTOSKELETAL DOMAIN
 LONGITUDINAL BUNDLES OF
INTERMEDIATE & THIN FILAMENTS
ASSOCIATED WITH DENSE BODIES
 DENSE BODIES alpha actinin

37. 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