Page 1
MUSCLE STRUCTURE AND PHYSIOLOGY
J. Rosenbluth, April 2009
Page 2
MUSCLE
• Skeletal muscle – Contraction mechanism– Excitation-contraction coupling
• Gross properties of skeletal muscle
• Cardiac, obliquely striated and smooth muscles
• Pathology/Clinical examples
Page 3
Skeletal muscle band pattern
Page 4
Double “antiparallel” array of myofilamnts (H.E.Huxley)
Page 5
Sliding filament model
Page 7
Myosin filament formation
Page 8
Low-angle X-ray diffraction of skeletal muscle (meridional pattern)
Page 9
Actin double helix
Page 10
Decorated F-actin
Page 11
Decorated F-actin attached to Z-disc
Page 12
Double hexagonal array (vertebrate skeletal muscle)
Page 13
Low-angle X-ray diffraction of skeletal muscle (equatorial pattern)
Page 14
Crossbridge position during relaxation (top) vs contraction (bottom)
Page 15
Cross-bridge Cycle
– Attached
– Released
– Cocked
– Force generating
– Attached
Page 17
Focal contraction (amphibian skeletal muscle)
Page 18
Triads (amphibian)
Page 19
Skeletal muscle triad (amphibian)
Page 20
Triad model(Franzini-Armstrong, C.)
Page 21
Actin filament with Tr and Tm
Page 22
Tropomyosin movement
Page 25
Length-Tension
Relationship
Page 26
Load-Velocity Relationship
Page 27
Twitch vs Tetanic Tension
Page 28
Cat Gastrocmenius
Page 29
Muscles Have Heterogenous Properties
Twitch Contractions
Page 30
Skeletal Muscle Fatigue
Page 33
Obliquely striated muscle (Ascaris), stretched
Page 34
Ascaris obliquely striated muscle
Page 35
Smooth muscle (“Myoelastic tissue”)
Page 36
Smooth muscle (cross section)
Page 37
Smooth muscle (Science 148:1337-1339)
Page 43
“Pseudohypertrophy” (Duchenne dystrophy)
Page 44
Charcot-Marie-Tooth disease
Page 45
Spinal muscular atrophy