Lecture 23: Pulmonary Circulation Flashcards
What agents constrict pulmonary arterioles?
Epinephrine, norepinephrine, angiotensin II, some prostaglandins
What agents dilate pulmonary arterioles?
Isoprotenerol, acetylcholine
High pressure/low flow circulation of lung
Supplies oxygenated blood to pulmonary system so that it can properly function
Low pressure/high flow circulation of lung
The more typical pulmonary circulation from pulmonary arteries to alveoli
Which is more compliant: the pulmonary arterial tree or the aorta?
Pulmonary arterial tree
Physiologic shunt
2% of blood in systemic circulation that has bypassed pulmonary capillaries and gone straight from wall of left atrium to left atrium; causes systemic blood to have slightly lower O2 content than blood equilibrated with alveolar air
What effect does exercise have on blood flow through the lungs and pulmonary arterial pressure?
Exercise causes blood flow to increase 4-7x, opening up more pulmonary capillaries and causing pulmonary arterial pressure to rise
Describe each blood flow zone; which is pathological?
Zone 1 = pathological, no blood flow
Zone 2 = occurs in apices of lung, intermittent flow
Zone 3 = occurs in lower 2/3 of lung, continuous flow
What change occurs between blood flow zones during exercise?
Zone 2 blood in apices can be converted to Zone 3
What occurs during left heart failure?
Blood dams up on the left side of the heart, and pressure in left atrium rises from normal 1-5 mmHg to 40-50 mmHg; pulmonary edema is likely to develop
What causes pulmonary edema and at what capillary pressure does it occur?
Left side heart failure, mitral valve disease, damage to pulmonary capillary membrane; occurs at > 25 mmHg
What is the result of blood flow in pulmonary artery during hypoxia?
Increased pressure in pulmonary artery
What is the result of blood flow in pulmonary artery during bronchial obstruction?
vessel constriction and decline in pH, which causes vasoconstriction in pulmonary vessels and vasodilation in other tissues
