Which body part is primarily affected by pressure changes during a dive?

Pressure changes during a dive primarily affect the ears due to the need for equalization. As a diver descends, the pressure increases, and the air in the middle ear is under greater pressure than the external water pressure. This difference can create discomfort and, if not equalized, can lead to barotrauma. Divers typically use techniques such as the Valsalva maneuver to equalize pressure in the ears by allowing the external air pressure to equal the pressure inside the eardrum.

While other body parts, such as the lungs, eyes, and nose, are also influenced by pressure changes, they do not experience the same necessity for equalization throughout varied depths as the ears. The lungs do have to manage the effects of pressure and gas laws, particularly during ascent and descent, but immediate discomfort and potential injury are more commonly associated with the ears because of their enclosed air space and dependency on maintaining equal pressure.