When diving doubles you will need to use your wing/BCD to compensation. Typically you can't control your buoyancy only with a drysuit with steel doubles and stage bottles so you will need to use your wing to offset buoyancy.
The structure of the throat is designed to prevent food from entering the lungs. Photo Credit matthewennisphotography/iStock/Getty Images. When food enters the lungs instead of the esophagus, it affects breathing and can cause choking and other problems.
Valves created by the lips and tongue keep food in the mouth and in place prior to swallowing. The valve created by the cricopharyngeous muscle at the top of the esophagus keeps air out of the digestive system during breathing. The valve created by the soft palate keeps food out of the nasal airway during swallowing. The soft palate elevates to prevent the bolus from refluxing into the nasal cavity. 2  The hyoid and larynx elevate and the epiglottis moves downward to protect the entrance to the airway. 3  This movement of the hyoid also initiates relaxation of the cricopharyngeus muscle and opening of the esophagus.