How would lung perfusion in a zone 1 area best be described?

(Answer to Q. 1)  ANS: C
Areas that experience higher airway pressure (e.g., during positive pressure ventilation) that equal or exceed local arteriole and capillary pressure will have reduced blood flow as a result of the opposing airway pressure (zone 1 airways).

(Answer to Q. 2)  ANS: C
Areas of regional lung hypoxia, as the result of reduced ventilation, congestion, and/or airway obstruction, can result in local pulmonary arterial vasoconstriction and cause blood flow to be shifted from these areas toward areas of higher O2 content and pulmonary vasodilation.

(Answer to Q. 3)  ANS: B
The third function is nonrespiratory and participates in the production, processing, and clearance of a large variety of chemicals and blood clots.

(Answer to Q. 4)  ANS: D
The vascular supply of the lungs is composed of the pulmonary and bronchial circulations. The pulmonary circulation carries mixed venous blood from the systemic circuit to the lungs to in-crease O2 and reduce carbon dioxide content of blood. The bronchial circulation provides sys-temic arterial blood to the airways and pleura to support their metabolic needs. A network of lymphatics is also involved in fluid transport from the lungs. The lymphatic system removes fluid from the lung tissue and pleural space and returns it to the systemic circulation.

(Answer to Q. 5)  ANS: B
The pulmonary circulation arises from the right heart (Figure 9-30) and carries the entire cardiac output through the lung each minute. O2-reduced systemic venous blood returns to the right heart via the inferior and superior venae cavae. This blood is pumped to the lungs by the right ventricle through the pulmonic semilunar valve and on to the trunk of the pulmonary artery.

(Answer to Q. 6)  ANS: D
The pulmonary venous system drains the capillary beds that have received O2 from the alveoli and delivers the oxygenated blood into the left atrium.

Ready for finals