CRL Quiz 3 Muscles 1


In skeletal muscle, the Ca2+ for contraction comes from


Muscle contraction starts when the muscle fiber depolarizes due to the release of calcium into the cytoplasm.


Put these events in the correct chronological sequence:

1 end plate potentials trigger action potentials
2 transverse tubules convey potentials into the interior of the cell
3 acetylcholine binds to receptors on the motor end plate
4 binding sites on actin are uncovered, allowing myosin to bind and carry out power strokes
5 Ca2+ is released from the sarcoplasmic reticulum
6 chemically regulated ion channels open, causing depolarization
7 Ca2+ ions bind to troponin-C, pulling on tropomyosin


As ATP binds to the myosin head at the beginning of a muscle contraction cycle...


Regulation of cross-bridge formation is accomplished by


A contraction that generates force and moves a load is known as __________, whereas one that generates force without movement is known as __________.


The components of muscle that allow force generation without a change in length are the


This question shows a diagram in which a weight hung from a simulation "muscle fiber". Initially the weight is supported below and no movement occurs. The support is then removed. What happens next?


This question shows two simulated muscles, A and B. that form an "opposing group". Muscle B is thicker. When they are both activated...


Why do lengthening (eccentric, pliometric) contractions more frequently cause injury to skeletal muscle fibres?