What is the Difference Between Myofibril and Muscle Fiber?

The main difference between a myofibril and a muscle fiber lies in their structure and organization within the muscle tissue. Here are the key differences:

• Myofibril: A myofibril, also known as a muscle fibril or sarcostyle, is a basic rod-like organelle of a muscle cell. Myofibrils are composed of long proteins, including actin, myosin, and titin, which are organized into thick, thin, and elastic myofilaments. These proteins are organized into sarcomeres, which are the functional units of contraction in a myofibril.
• Muscle Fiber: A muscle fiber, also known as a muscle cell, is a long, tubular shaped cell that is part of the muscle tissue. Each muscle fiber is composed of thousands of myofibrils, which run the entire length of the muscle fiber. Muscle fibers are the basic units of muscle tissue and are responsible for muscle contractions.

In summary, myofibrils are the basic rod-like units within muscle fibers, while muscle fibers are the long, tubular cells that make up muscle tissue. Myofibrils contain sarcomeres, which are responsible for muscle contractions, and they are organized into parallel structures within the muscle fiber.

Comparative Table: Myofibril vs Muscle Fiber

Here is a table comparing the differences between myofibrils and muscle fibers:

In summary, myofibrils are the basic rod-like units of a muscle fiber and are composed of two types of myofilaments: thin and thick filaments. They are cylindrical organelles with a diameter of approximately 1.2 µm. Muscle fibers, on the other hand, are tubular shaped cells that contain numerous myofibrils, and they have a diameter of up to 100 µm and can be several centimeters long. Muscle fibers also contain other organelles, including mitochondria, and are responsible for muscle contraction.