Muscle Parts Label

Label the parts of thick and thin filaments in skeletal muscle.

• "C" = portion of a thin filament

• "B" = myosin molecule

• "E" = actin

• "A" = portion of a thick filament

• "A" = tropomyosin

Label the parts of the neuromuscular junction.

• axon terminal of motor neuron = A

• synaptic vesicle = B

• synaptic cleft = C

• ACh = D

Label the steps in excitation-contraction coupling in skeletal muscle.

• A= Action potential is propagated along the sarcolemma and down the T tubules.

• B= The SR is stimulated to release calcium ions.

• C= Calcium binds to troponin and removes the blocking action of tropomyosin.

• D = Cross bridge formation occurs and the contraction mechanism is initiated.

Label the steps of the cross bridge cycle in skeletal muscle.

• C= cross bridge detachment

• B= the power stroke or working stroke

• A = cross bridge formation

• D = cocking of myosin head