Certified Personal Trainer (NSCA) Practice Exam

What is the correct sequence of components from smallest muscle structure to largest muscle structure?

1. Fascia, perimysium, epimysium, endomysium

2. Myofilament, myofibril, fiber, fasciculus

3. Endomysium, epimysium, perimysium, fascia

4. Muscle cell, fasciculus, myofibril, fiber

The correct answer is: Myofilament, myofibril, fiber, fasciculus

The correct sequence from smallest muscle structure to largest muscle structure is represented accurately by myofilament, myofibril, fiber, and fasciculus. Myofilaments are the smallest structures and are the contractile proteins within muscle fibers, primarily consisting of actin and myosin. When myofilaments group together, they form myofibrils, which are elongated structures that run the length of the muscle fiber and are essential for muscle contraction. These myofibrils are packaged together within a muscle fiber (also known as a muscle cell), which is a larger structure that contains many myofibrils. Finally, multiple muscle fibers come together to form a fasciculus, which is a bundle of muscle fibers. This hierarchy illustrates the organization of muscle tissue, showing how smaller components combine to form larger structures essential for muscle function. Understanding this sequence is crucial for comprehending how muscle contraction occurs and how muscles are structured at a cellular level.