Respiratory System Mechanics Flashcards

Surfactant: A mixture of lipids and proteins that coats alveolar surfaces, acting as a detergent to reduce surface tension and prevent alveolar collapse.
Surface Tension: The force arising from the unequal attraction of water molecules at the liquid surface, which contributes to the reduction of hollow spaces in the lungs.
Intrapleural Pressure: The pressure within the pleural cavity is vital for lung function and preventing collapse.
Pneumothorax: A condition characterized by the presence of air in the pleural cavity, resulting in equal intrapleural and atmospheric pressure, which can lead to lung collapse.
Atelectasis: Refers to the total or partial collapse of the lung, often a consequence of pneumothorax.

Negative intrapleural pressure is maintained by two opposing forces:
- The lung's tendency to recoil due to elastic properties and alveolar surface tension.
- The compressed chest wall's natural recoil that wants to expand outward.
These forces combine to create a partial vacuum in the pleural cavity, essential for lung inflation.

Surface tension does not increase the size of the alveoli; it acts to decrease them.
Surfactant does not enhance the attraction of water molecules; rather, it reduces this attraction to facilitate lung function.

Just before inspiration, the intrapleural pressure is lower than the alveolar pressure, facilitating airflow into the lungs.
Pneumothorax equalizes intrapleural pressure with atmospheric pressure, leading to compromised lung mechanics.
A pneumothorax can directly result in atelectasis, causing respiratory distress.

Administering surfactant enhances airflow within the alveoli and improves lung mechanics.
The quickest method to address a collapsed lung (atelectasis) involves removing air from the intrapleural space to restore negative pressure.

Opening a valve in a glass bell jar demonstrates a simulated pneumothorax, showcasing the connection between pressure changes and lung volume.
In experiments, pneumothorax typically leads to subsequent atelectasis due to the mechanical failure of lung inflation.