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.
Each muscle fiber contains myofibrils, which are very long chains of sarcomeres, the contractile units of the cell. A cell from the biceps brachii muscle may contain 100,000 sarcomeres. The myofibrils of smooth muscle cells are not arranged into sarcomeres. The sarcomeres are composed of thin and thick filaments.