Gas Exchange Flashcards
What is diffusion?
The net movement of particles from an area of higher concentration to an area of lower concentration.
Diffusion continues until particles are evenly distributed throughout the liquid or gas.
What is the concentration gradient?
The path from an area of higher concentration to an area of lower concentration.
Particles diffuse down a concentration gradient.
Is diffusion an active or passive process?
Passive process - no energy is needed for it to happen.
What do gas exchange surfaces have in common?
They have a large surface area to volume ratio and are thin, often one layer of epithelial cells.
How does temperature affect the rate of diffusion?
The rate of diffusion increases with temperature because molecules have more kinetic energy and move faster.
What is the relationship between surface area to volume ratio and exchange rate?
The smaller the surface area to volume ratio, the slower the rate of exchange.
What is the gas exchange surface in mammals?
The alveolar epithelium in the lungs.
What happens to oxygen in the lungs?
Oxygen diffuses out of the alveoli, across the alveolar epithelium and the capillary endothelium, and into the blood.
What happens to carbon dioxide in the lungs?
Carbon dioxide diffuses into the alveoli from the blood and is breathed out.
What features of mammalian lungs increase the rate of gas exchange?
- Lots of alveoli for a large surface area
- Alveolar epithelium and capillary endothelium are one cell thick
- Good blood supply from capillaries
- Breathing refreshes air in the alveoli
Fill in the blank: The smaller the surface area to volume ratio, the _______.
slower the rate of exchange.
True or False: All gas exchange surfaces are thick and have a small surface area to volume ratio.
False.
