So the muscle cell is also known as the muscle fiber or the myocide. And inside our muscle cell we contain many of these myofibrils as shown in the following diagram. So if we take a cross section of the muscle cell we get the following diagram. We have many of these red regions which are aromiofibels. Now notice the cytoplasm has its own name. The cytoplasm of the muscle fiber is known as arosarco plasma.