Advanced Patient Assessment Practice Exam

Which of the following sequences of events best describes the cough mechanism?

1. Inspiration, forceful opening of glottis, contraction of diaphragm

2. Inspiration, closure of glottis, forceful opening of glottis

3. Opening of glottis, relaxation of diaphragm, closure of glottis

4. Opening of glottis, contraction of diaphragm, explosive release of trapped intrathoracic air

The correct answer is: Inspiration, closure of glottis, forceful opening of glottis

The correct sequence that describes the cough mechanism begins with inspiration, followed by closure of the glottis, and then a forceful opening of the glottis. This process is vital for effectively expelling irritants or secretions from the airways. Initially, the act of inspiration allows air to enter the lungs, which is essential for creating a buildup of pressure within the thoracic cavity. Once inhalation is complete, the glottis closes, trapping the inspired air. The closure of the glottis is crucial because it increases the pressure in the thoracic cavity, which is necessary for an effective cough. Subsequently, when the glottis is forcefully opened, the built-up air escapes rapidly, producing a cough that helps clear the airway. In contrast, other sequences do not accurately follow the physiological processes involved in coughing. For instance, option A misplaces the sequence of events by incorrectly suggesting that the glottis is opened forcefully after the diaphragm contracts. Option C does not align well with the actual mechanism, as it incorrectly sequences the glottis opening and diaphragm relaxation. Similarly, option D misrepresents the order of events and fails to capture the glottis closure, which is essential for creating the necessary pressure for