Question

what is the result of inspiration?
multiple choice
an increased alveolar volume causes increased alveolar pressure
an increased alveolar volume causes decreased alveolar pressure
a decreased alveolar volume causes increased alveolar pressure
a decreased alveolar volume causes decreased alveolar pressure
an increased alveolar pressure causes decreased alveolar volume

Explanation:

During inspiration, the diaphragm and external intercostal muscles contract, increasing the volume of the thoracic cavity. According to Boyle's law ($P_1V_1 = P_2V_2$, at a constant temperature, pressure is inversely proportional to volume), when the alveolar (lung - related) volume increases ($V$ increases), the alveolar pressure ($P$) decreases. This pressure gradient (lower alveolar pressure compared to atmospheric pressure) causes air to flow into the lungs.

Answer:

An increased alveolar volume causes decreased alveolar pressure.