Which of the following is NOT one of the three parts of a muscle?

The three parts of a muscle typically refer to the types of muscle tissue: skeletal, cardiac, and smooth muscles. Skeletal muscle is responsible for voluntary movements, cardiac muscle makes up the heart and is involuntary, and smooth muscle is found in various organs and is also involuntary.

In this context, the answer identifies "dendrite" as the option that does not belong. Dendrites are actually part of neurons and are extensions that receive signals from other neurons. They are not a component of muscle tissue. On the other hand, tendon refers to the fibrous connective tissue that attaches muscle to bone, and while skeletal and cardiac describe types of muscle tissue, they are indeed part of the muscle classification system. Thus, the inclusion of "dendrite" aligns with it being distinctly related to the nervous system rather than muscle structure.