Arrange the following steps of muscle fiber contraction in the correct sequence.  1. The muscle impulse reaches the sarcoplasmic reticulum and calcium is released.  2. Thin filaments are pulled over the thick filaments.  3. Calcium floods the sarcoplasm and binds to troponin molecules.  4. An impulse travels across the sarcolemma and through the transverse tubules.  5. The muscle fiber shortens.  6. Myosin heads bind to actin, forming cross-bridges. 

Bones of a synovial joint are held together by 

The functional unit of muscle contraction is the ____

Limb bones are part of the ______ skeleton.

During muscle contractions myosin heads move to _____.

A suture is an example of a(n) _____ joint.

Compact bone has _____ and spongy bone has _____ 

A tendon is ­_____, whereas an aponeurosis is _____. 

Binding sites on the surface of actin allow the formation of attachments (cross-bridges) with molecules of ______. 

_______ enhances the absorption of calcium from food, and therefore helps raise blood calcium level