Final answer:
The correct order of events for inspiration is: the diaphragm and intercostal muscles contract, Pip decreases, transpulmonary pressure increases, and Palv decreases to less than Patm.
Step-by-step explanation:
To understand the process of inspiration, we need to consider the sequence of physiological events that occur. The correct order starts with the diaphragm and intercostal muscles contracting. This contraction expands the chest cavity, creating more space for the lungs to expand. As the volume of the thoracic cavity increases, the intrapleural pressure (Pip) decreases. This expanding volume also leads to a decrease in intra-alveolar pressure (Palv) to less than atmospheric pressure (Patm). The decrease in Palv allows air to flow into the lungs. With a lower Pip and a lower Palv, the transpulmonary pressure, which is the difference between the Palv and Pip, increases and facilitates lung expansion.
Therefore, the correct order of events for inspiration is:
Diaphragm and intercostals contract.
Pip decreases.
Transpulmonary pressure increases.
Palv decreases to less than Patm.