Flashcards in Chapter 3: Transport in cells Deck (7):
How is diffusion maximised in the circulatory system?
Alveoli have thin walls with a high surface area, and capillaries have walls only one membrane thick
What are alveoli?
Tiny sacs in the lungs where gas exchange between blood and the air takes place
How are the lungs adapted to their function?
Moist membranes allow for faster diffusion, thin linings, rich blood supply, breathing (ventilation)
What factors affect diffusion?
Temperature, gradient, surface area
What are some examples of osmosis (diffusion of water)?
Transpiration in plants, where water enters root hair cells due to the concentration imbalance
What are some examples of diffusion in other animals?
Insects get oxygen by diffusion (they have no lungs). Oxygen diffuses through the high-surface area walls of their spiracles (tubes that run into their bodies). Insects cannot grow too large because otherwise their surface area/volume ratio would be too low and they wouldn't get enough oxygen
Fish gills have high surface areas for maximum diffusion