Many of the symptoms you describe are vague and could be due to a number of things including Provera. Some of the common side effects of this medication include weight gain, weak bones, headaches, fatigue, swelling. These symptoms could also be caused by a number of things such as thyroid problems.
Myofibrils are assembled of repeated structures called sarcomeres â the smallest functional unit of muscle fiber. Each sarcomere is formed of actin (called thin) and myosin (called thick) filaments arranged in a precise order and of protein complexes which support the filament structures.
(1) Long, cylindrical organelle in striated muscle cells, composed mainly of actin and myosin filaments that run from one end of the cell to the other. (2) The contractile unit of a striated muscle. Supplement. The actin and myosin filaments are organized into repeated subunits along the length of the myofibril.These subunits are called sarcomeres. Word origin: myo - (muscle) + fibril. Related term: myofibrillar (adjective).2) The contractile unit of a striated muscle. Supplement. The actin and myosin filaments are organized into repeated subunits along the length of the myofibril. These subunits are called sarcomeres. Word origin: myo - (muscle) + fibril. Related term: myofibrillar (adjective). Synonym: 1  sarcostyle (obsolete).