What are the three parts of a muscle?

The three parts of a muscle are referred to as the origin, belly, and insertion. The origin is the fixed point that doesn't move when the muscle contracts; it is typically located closer to the center of the body or the skeleton. The belly, also known as the muscle body, is the central, fleshy part of the muscle that contracts and relaxes to produce movement. The insertion is the point where the muscle attaches to the bone that is moved during contraction. Understanding these components is essential for comprehending how muscles function in the human body and how they facilitate movement.

The other choices relate to different concepts. The first option discusses parts of certain structures in anatomy, while the third option refers to terms that might describe the ends of elongated structures but are not specific to muscle anatomy. The last option categorizes muscles based on their function rather than their anatomical parts.