What is the primary function of lung capillary endothelial cells in the respiratory system?

What is the primary function of lung capillary endothelial cells in the respiratory system?

• A. Produce mucus for airway protection
• B. Secrete urokinase
• C. Facilitate gas exchange
• D. Regulate blood flow in the lungs

Answer: (C)

The primary function of lung capillary endothelial cells is to facilitate gas exchange. These cells line the small blood vessels in the lungs and provide a critical interface between the air in the alveoli and the blood in the capillaries. The structure of these endothelial cells is highly specialized, allowing for efficient diffusion of oxygen and carbon dioxide. This gas exchange is essential for respiration, enabling oxygen to enter the bloodstream while carbon dioxide is released from the blood to be exhaled. Lung capillary endothelial cells play a role in creating a barrier that is thin enough to allow for the quick diffusion of these gases, but they also help to maintain the integrity of the blood-air barrier, ensuring that substances within the blood do not enter the alveoli. The efficiency of this gas exchange is vital for maintaining proper oxygenation of the body and the removal of carbon dioxide, which is a metabolic waste product.

The primary function of lung capillary endothelial cells is to facilitate gas exchange. These cells line the small blood vessels in the lungs and provide a critical interface between the air in the alveoli and the blood in the capillaries. The structure of these endothelial cells is highly specialized, allowing for efficient diffusion of oxygen and carbon dioxide. This gas exchange is essential for respiration, enabling oxygen to enter the bloodstream while carbon dioxide is released from the blood to be exhaled.

Lung capillary endothelial cells play a role in creating a barrier that is thin enough to allow for the quick diffusion of these gases, but they also help to maintain the integrity of the blood-air barrier, ensuring that substances within the blood do not enter the alveoli. The efficiency of this gas exchange is vital for maintaining proper oxygenation of the body and the removal of carbon dioxide, which is a metabolic waste product.