Structure of the thorax Flashcards
What surfaces do lungs have in them?
A very large gas exchange surface
What have large, active animals like mammals evolved?
Complex blood systems and lungs
What do the complex blood systems and lungs provide?
A large surface area for the efficient diffusion of oxygen and carbon dioxide
Where does gas exchange take place?
In millions of tiny air sacs called alveoli
What adaptations do alveoli have?
Adaptations that increase the diffusion rate
Whast do the walls of the alveoli consist of?
A single layer of thin, flattened, epithelial cells
When does diffusion happen faster?
When molecules only have to travel short distances
When is diffusion also faster?
When there’s a bigger difference in concentration between 2 regions
What does the blood flowing through the rich network of capillaries around the alveoli do?
What does all this ensure? (What is true for carbon dioxide)
Carries away the oxygen that has diffused through the alveolar walls
That there’s always a higher concentration of oxygen inside the alveoli than in the blood (The reverse is true for carbon dioxide)
What are the alveolar walls fully permeable to?
Dissolved gases
Where can oxygen and carbon dioxide easily pass through?
The membranes of the epithelial cells
