Muscles can only contract and relax, so they always work in pairs called antagonistic muscles. Skeletal muscle is joined to bones. Its cells contract to make bones move and joints bend.

The human body contains three kinds of muscle tissue: skeletal, smooth ... that tell cardiac muscle cells to contract and relax. The pacemaker cells control heart rate and determine how fast ...

Skeletal muscles can convert chemical energy into ... are muscles that are not under conscious control. Their contraction and relaxation are regulated by the autonomic nervous system, which ...

Involuntary cardiac and smooth muscles are responsible for contraction of the heart and movement of substances through hollow organ systems, respectively, and voluntary skeletal muscles are ...

Since calcium is essential for muscle contraction and relaxation, they hoped to learn ... isolated seven proteins from an extract of rabbit skeletal muscle sarcoplasmic reticulum, and when they ...