6.4 Gas Exchange Flashcards
What does ventilation do?
It maintains concentration gradients of oxygen and carbon dioxide
describe the function of Type 1 pneumocytes
make up the alveolus wall and allow diffusion
describe the function of type 2 pneumocytes
they secrete a solution containing surfactant that creates a moist surface in the alveoli
what is a surfactant?
substance which reduces surface tension of a liquid in which it is dissolved
how is air carried to the lungs?
through the trachea and bronchi
What normally prevents the membranes of the alveoli from sticking together during expiration?
surfactant which keeps the alveoli moist and prevents them from sticking together
What feature of alveoli adapts them to efficient gas exchange?
A dense network of capillaries surrounds them.
Which muscle action is associated with an increase in the volume of the thoracic cavity during inspiration?
The diaphragm contracts.
What change occurs to the pressure and volume of the lungs when the external intercostal muscles contract?
Pressure decreases and volume increases.
