Final answer:
The two types of muscles that form the walls of the pharynx are skeletal muscles and constrictor muscles.
Step-by-step explanation:
The two types of muscles that form the walls of the pharynx are the skeletal muscles and the constrictor muscles.
The skeletal muscles, specifically the elevator muscles, contract during swallowing to raise and expand the pharynx to receive food. The constrictor muscles then contract to force the food bolus into the esophagus and initiate peristalsis.