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.
Actin filaments are anchored into the z-line of a sarcomere. The thick myofilaments are composed mainly of the protein myosin. It is the orderly overlapping of the actin and myosin filaments that give cardiac and skeletal muscle their striated appearance (light and dark bands). myofibril is a cylindrical bundle of contractile proteins found within the muscle cell. Note that there are several myofibrils within each muscle cell. It is the arrangement of the contractile proteins within the myofibril that cause the striated appearance of skeletal and cardiac muscle.