[Campbell Biology P.955] The "Visual Skills" section asks to explain why liquid might be eje... | Practice Question

The "Visual Skills" section asks to explain why liquid might be ejected from nostrils when laughing while drinking water. Based on the information provided, what is the most plausible explanation for this phenomenon?

  • A: Laughing causes a sudden contraction of the stomach, forcing liquid upward.
  • B: Laughing involves exhalation, which, if the epiglottis is not fully covering the trachea during swallowing, can force liquid from the trachea back up and out through the nasal cavity.
  • C: The act of laughing completely relaxes the esophageal sphincter, causing ingested liquid to reflux into the pharynx and nasal passages.
  • D: The sudden pressure changes from laughing cause the glottis to permanently close, trapping liquid in the pharynx and forcing it upwards.

Explanation

The text explains that swallowing involves the epiglottis covering the trachea to prevent food/liquid entry. It also states that laughing involves exhaling. If one tries to swallow and laugh exhale simultaneously, the epiglottis might not fully cover the trachea. When exhaling, air forcefully expelled from the lungs, if mixed with liquid that entered the trachea, can propel that liquid back up and out through the pathway of least resistance, which includes the nasal cavity.