PHYSIOLOGY
NEUROMUSCULAR JUNCTION TRANSMISSION
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Actin
|
|
|
Z line
|
|
|
Myosin
|
|
|
M Line
|
Detailed explanation-1: -The main component of the thick filament is myosin-II (two myosin heads); each myosin-II consists of two identical myosin heavy chains (MHC). Each MHC consists of a globular head region connected to a long coiled-coil tail region via an elastic hinge region (Figure 4).
Detailed explanation-2: -The A band is the region of the sarcomere that contains the myosin (thick) filaments, regardless of overlap. This means that myosin is exclusive to the A band, but that this region contains both actin and myosin due to overlap.
Detailed explanation-3: -A single thick filament contains >200 perfectly aligned myosin molecules assembled into highly ordered bundles in which the globular motor head domains face outward and the long rod regions face inward forming a bipolar filament (20, 176) (Fig.
Detailed explanation-4: -Most of the cytoplasm consists of myofibrils, which are cylindrical bundles of two types of filaments: thick filaments of myosin (about 15 nm in diameter) and thin filaments of actin (about 7 nm in diameter).