Function of Pharynx
The pharynx is a crucial part of the digestive and respiratory systems in the human body. It serves several important functions to ensure proper functioning of these systems.

1. Passage of Food and Liquids
The pharynx acts as a passageway for food and liquids to move from the mouth to the esophagus. When swallowing, the muscles in the pharynx contract to push the food towards the esophagus, allowing it to reach the stomach for digestion.

2. Passage of Air
In addition to food and liquids, the pharynx also plays a role in the passage of air from the nose and mouth to the trachea. It helps in directing air towards the lungs for respiration.

3. Protection
The pharynx also serves a protective function by preventing food and liquids from entering the airway. The epiglottis, a flap of tissue in the pharynx, closes off the trachea during swallowing to ensure that food goes down the esophagus and not into the lungs.

4. Resonance Chamber
Another important function of the pharynx is to act as a resonance chamber for sound production. It helps in modifying the pitch and tone of the voice by altering the size and shape of the pharynx.

5. Immune Function
The pharynx contains lymphoid tissue that helps in fighting infections and pathogens that enter the body through the mouth and nose. This immune function helps in protecting the body from respiratory illnesses and other infections.
In conclusion, the pharynx plays a vital role in the proper functioning of the digestive and respiratory systems by facilitating the passage of food, liquids, and air, providing protection, acting as a resonance chamber for sound production, and contributing to the body's immune function.