What event is characteristic of the function in Zone 1 of the lung?
A)Blood flow through the pulmonary capillary bed increases in regular increments.
B)Alveolar pressure is lesser than venous and arterial pressures.
C)The capillary bed collapses, and normal blood flow ceases.
D)Blood flows through Zone 1, but it is impeded by alveolar pressure.

Question

Quizplus · Accepted Answer

Alveolar pressure exceeds pulmonary arterial and venous pressures in Zone 1. The capillary bed collapses, and normal blood flow ceases. Zone II is the portion where alveolar pressure is greater than venous pressure but not greater than arterial pressure. Blood flows through zone II, but it is impeded by alveolar pressure. Zone II is normally above the level of the left atrium. In zone III, arterial and venous pressures are greater than alveolar pressure and blood flow is not affected by alveolar pressure. Zone III is in the base of the lung. Blood flow through the pulmonary capillary bed increases in regular increments from the apex to the base.

What Event Is Characteristic of the Function in Zone 1