The symptoms of a stroke are different, depending on where in the brain the stroke is located, and doctors can use the symptoms to pinpoint the site of the stroke. In the case of a brain stem stroke, the patient often experiences vertigo, slurred speech, and difficulty speaking.
The smallest functional unit in a myofibril is a sarcomere. A sarcomere is composed of thin (actin) and thick (myosin) filaments. Actin slides past myosin when the muscle contracts.
Myofibrils are composed of long proteins including actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thick and thin filaments called myofilaments, which repeat along the length of the myofibril in sections called sarcomeres. Thin filaments consist primarily of the protein actin, coiled with nebulin filaments. 2  Actin, when polymerized into filaments, forms the ladder along which the myosin filaments climb to generate motion. 3  Thick filaments consist primarily of the protein myosin, held in place by titin filaments.