Diffusion through cell membranes Flashcards
1
Q
Where does gas exchange happen?
A
In the lungs.
2
Q
What is the job of the lungs?
A
To transfer oxygen into the blood and to remove waste carbon dioxide.
3
Q
How do the lungs complete gas exchange?
A
They contain millions of little air sacs called alveoli.
4
Q
What gas exchange takes place in the alveoli?
A
Gas exchange of oxygen and carbon dioxide.
5
Q
How are the alveoli specialised to maximise diffusion of oxygen and carbon dioxide?
A
They have:
- An enormous surface area (about 75m² in humans)
- A moist lining for dissolving gases
- Very thin walls
- A good blood supply
6
Q
What is the inside of the small intestine covered with?
A
Millions and millions of tiny projections called villi.
7
Q
What do villi do?
A
They increase the surface area of the intestinal walls so that digested food is absorbed more quickly into the blood.
8
Q
What do the villi have?
A
- A single layer of surface cells.
- A very good blood supply to assist with quick absorption.
