Learn: The Mammalian Lung - Ventilation and Gas Exchange

Welcome!You've already studied gas exchange surfaces and Fick's Law. Now, let's build on that by learning how ventilation and gas exchange happen in the mammalian lung.

Overview of VentilationVentilation is the process of moving air in and out of the lungs. It ensures oxygen is brought into the body and carbon dioxide is removed. This constant air movement maintains the concentration gradient needed for efficient gas exchange.

How Ventilation WorksThe diaphragm and intercostal muscles play key roles in ventilation. During inhalation, the diaphragm contracts and flattens, while the intercostal muscles lift the ribs. This increases chest volume and decreases pressure, drawing air into the lungs.

Exhalation ExplainedExhalation is mostly passive. The diaphragm and intercostal muscles relax, decreasing chest volume and increasing pressure. Air is pushed out of the lungs as a result.

Gas ExchangeGas exchange occurs in the alveoli. Oxygen diffuses into the blood from the alveoli, while carbon dioxide diffuses out of the blood into the alveoli. This process relies on the concentration gradients maintained by ventilation.

The Role of SurfactantA surfactant is a substance that reduces surface tension in the alveoli, preventing them from collapsing. It ensures the alveoli remain open for efficient gas exchange.

Review Time!Great work! You've learned about ventilation, gas exchange, and the role of the alveoli. Now let's test your understanding with a few questions.