Questions and Answers
What is the pressure gradient driving flow in the pulmonary circulation?
Which of the following best describes the compliance of pulmonary arteries compared to systemic vessels?
What proportion of cardiac output do the lungs receive?
How long does blood take to travel across pulmonary capillaries during rest?
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Which statement regarding pulmonary blood flow is accurate?
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What type of blood is carried by the pulmonary arteries?
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What is the mean pulmonary arterial pressure?
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What is the PO2 in systemic arterial blood?
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Study Notes
Characteristics of Pulmonary Circulation
- Exhibits high blood flow with low resistance, significantly lower than systemic circulation (10-50 times).
- Right ventricle wall is approximately 30% the thickness of the left ventricle.
- Walls of pulmonary arteries are around 30% the thickness of the aorta, resulting in greater compliance and reduced elasticity compared to systemic vessels.
- Pressure gradient within the pulmonary system is about 7 mmHg.
- Mean pulmonary arterial pressure averages 15 mmHg, while pulmonary venous pressure is about 8 mmHg.
- Blood flow in pulmonary circulation matches that of systemic circulation.
- Blood velocity in the pulmonary artery is similar to that in the aorta, at 0.4 m/sec.
- Blood transit time through pulmonary capillaries is 0.75 seconds at rest and 0.3 seconds during exercise.
- Total blood volume in pulmonary vessels is approximately one liter, with around 100 ml contained within the capillaries.
- Lungs uniquely receive 101% of cardiac output, combining 100% from the right ventricle and an additional 1% from the left ventricle via bronchial arteries.
- Pulmonary capillaries feature large diameters and numerous anastomoses, allowing each alveolus to be surrounded by a capillary network, influenced by negative intrathoracic pressure.
Physiologic Shunt
- Connection between bronchial capillaries and pulmonary capillaries enables some blood from bronchial veins to drain into pulmonary capillaries, bypassing the right ventricle.
- Results in discrepancies in oxygen partial pressure:
- PO2 in alveoli and pulmonary veins is 100 mmHg.
- PO2 in systemic arterial blood measures 95 mmHg.
- The pulmonary artery carries deoxygenated blood, while the pulmonary veins transport oxygenated blood.
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Description
Explore the key characteristics of pulmonary circulation in this quiz. Understand the differences in pressure and flow between the pulmonary and systemic circulatory systems. Test your knowledge on the structure and function of the right ventricle and pulmonary arteries.
