A muscle that is primarily responsible for a given action is termed a(n) agonist antagonist fixator originator synergist

Question Analysis

In the context of muscle anatomy and physiology, identifying the role of specific muscle types is essential in understanding how movement occurs in the body.

Relevant Concepts

1. Agonist: This is the primary muscle responsible for a specific movement.
2. Antagonist: The muscle that opposes the action of the agonist.
3. Fixator: A muscle that stabilizes a joint to allow the agonist to work effectively.
4. Originator: This term is not commonly used in muscle dynamics.
5. Synergist: Muscles that assist the agonist in performing a movement.

Conclusion

The correct term for a muscle that is primarily responsible for a given action is agonist. The agonist works to contract and create the movement, while other types of muscles like antagonists and synergists play supportive roles.

Final Answer

Agonist.