Gas exchange Flashcards
(14 cards)
What are two essential functions of gas exchange
• Oxygen intake. We need to get oxygen from the air into the blood, for our cells to use in respiration.
• Carbon dioxide removal. We also need to remove waste carbon dioxide from the blood into the air.
Where does gas exchange happen
in the alveoli
How are the alveoli adapted for gas exchange
• alveoli give the lungs a large surface area for diffusion.
• Lots of tiny blood vessels (capillaries) carry the gases away, maintaining the concentration gradient.
• Thin walls (one cell thick) give short diffusion path.
• Moist walls allow gasses to dissolve.
where do gases move by diffusion
(concentration)
The gases move by diffusion from a high concentration to a low concentration.
How does oxygen diffuse during gas exchange
• O2 dissolves in moisture lining
• Diffuses through Alveolus wall
• Diffuses into blood
• Is absorbed by red blood cells
•O2 moves from high to low concentration
gas % composition
Gas | inhaled air | exhaled air
————————————————-
Oxygen | 21% | 16%
Carbon | 0.04% | 4%
dioxide.
Nitrogen| 79% | 79%
Water |small am | large amount
vapour
Oxygen composition in words
• We breathe in more oxygen than we breathe out
• We breathe in less carbon dioxide than we breathe out.
• We breathe in the same amount of Nitrogen that we breathe out.
• We breathe in less water vapour than we breathe out.
why would limewater turn milky when breathed into
Because we breathe in less carbon dioxide than we breathe out.
What is the purpose of the limewater test
to check if carbon dioxide is present.
Carbon dioxide
Carbon dioxide diffuses from the blood into the air in the alveoli
Oxygen
Oxygen diffuses from the air in the alveoli into the blood
How are the alveoli adapted for gas exchange (short)
•Good blood supply
•Large surface area
•Thin walls
•Moist lining
slightly cloudy explanation
Inspired air is drawn in through this limewater, it goes slightly cloudy as there is little carbon dioxide.
very cloudy water explanation
Expired air is bubbled through this limewater. It turns very cloudy. showing the carbon dioxide in this is increased.
