Muscle contraction is the tightening, shortening, or lengthening of muscles when you do some activity. It can happen when you hold or pick up something, or when you stretch or exercise with weights.

In a serendipitous discovery, UC San Diego researchers using cryo-EM technology captured the first visualizations of the 3-D structure of the muscle acetylcholine receptor in fetal and adult muscles.

When labor begins, the uterus must coordinate rhythmic, well-timed contractions to deliver the baby safely. While hormones such as progesterone and oxytocin are key contributors to that process, ...