2.7: Absorption of Materials Flashcards
Describe absorption in the body
Oxygen and nutrients from food must be absorbed into the bloodstream to be delivered for respiration. Waste materials, such as carbon dioxide, must be removed from cells into the bloodstream
Why is it important that tissues contain capillary networks?
To allow the exchange of materials at cellular level
What is absorption?
A process where a substance is ‘taken up’ into a tissue, usually crossing a membrane
What makes the alveoli good at absorption?
3
- Good blood supply
- Large surface area
- Thin walls
How does good blood supply make the alveoli good at absorption?
To take away the materials absorbed
How does a large surface area make the alveoli good at absorption?
To absorb more materials
How does thin walls make the alveoli good at absorption?
To speed up absorption
How are lungs adapted for gas exchange?
They consist of a large number of alveoli providing a large surface area
What are alveoli?
Tiny air sacs shaped like bunches of grapes surrounded by lots of capillaries
What happens during gas exchange in the alveoli?
- Oxygen is breathed in and crosses the thin alveolar walls, into the bloodstream
- Carbon dioxide - waste product from respiration - leaves the capillaries and crosses into the alveoli. It is then breathed out
How does the small intestine absorb nutrients from food?
The walls of the small intestine are folded into thousands of tiny villi. This increases the surface area to allow more nutrients to be absorbed.
What makes the small intestines good at absorbing nutrients?
- Thin Walls
- Blood Capillaries
- Lacteal
How does thin walls make the small intestines good at absorbing nutrients?
Allows food to be absorbed quickly and easily
How does blood capillaries make the small intestines good at absorbing nutrients?
Provides a rich blood supply and efficiently absorbs amino acids and glucose
How does lacteal make the small intestines good at absorbing nutrients?
Absorbs the products of fat digestion - fatty acids and glycerol
