Chapter 23.6, Problem 6WDT

Summary Introduction

To determine: What can account for the blood PO₂ arriving at systemic capillaries with a lower PO₂ value than when it left the pulmonary capillaries.

Concept introduction: When the partial pressure for a specific gas is greater in one region than in another region, a partial pressure gradient exists. If a partial pressure gradient exists between two regions for a particular gas, then the gas moves to the area of lower partial pressure gradient from the area of higher partial pressure gradient. This movement may continue until the partial pressures in both the regions become equal. The respiratory gas exchange in both systematic and alveolar gas exchanges is dependent upon partial pressure gradients.