Final answer:
The cricothyroid muscle controls the tension and pitch of the vocal cords in the larynx.
Step-by-step explanation:
The cricothyroid muscle is responsible for controlling the tension and pitch of the vocal cords in the larynx. When this muscle contracts, it elongates and tenses the vocal cords, resulting in a higher pitch of voice. It is the only muscle that innervates the cricothyroid joint, which is innervated by the external branch of the superior laryngeal nerve.