Pupil sheet · Absorption
Absorption — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. identify
A vitamin is destroyed by the acid in the stomach. It is sold in a capsule with a coating that does not dissolve in the stomach. Which row shows where the coating should dissolve, so that as much of the vitamin as possible reaches the blood, and the reason?
| Row | Where the coating should dissolve | Reason |
|---|---|---|
| A | small intestine | nutrients are absorbed there |
| B | colon | most nutrients are absorbed there |
| C | small intestine | the vitamin is digested there |
| D | colon | food stays there longest |
Circle one answer.
- A
- B
- C
- D
2. identify
Which two parts of the alimentary canal absorb almost all of the water?
Tick every correct statement.
- stomach
- oesophagus
- small intestine
- colon
3. calculate
Supplement. A 2.0 mm² patch of the lining of a pig's small intestine is studied. The villi on the patch give it a surface of 12 mm². With the microvilli on the epithelial cells included, the total surface of the patch is 300 mm². (a) Calculate how many times the villi multiply the surface of the flat patch. (b) Calculate how many times the microvilli multiply the surface of the villi.
(a) Factor for the villi: ______________ unit ________
(b) Factor for the microvilli: ______________ unit ________
4. calculate
Supplement. A dog's small intestine is about 4.0 m long and 1.6 cm across. If it were a smooth tube, its inner surface area would be π × diameter × length. Calculate this area in m². Use π = 3.14.
Inner surface area of a smooth tube: ______________ unit ________
5. predict
Supplement. A dye that colours only lymph is injected into the wall of the small intestine. A villus is then cut along its length. Where in the villus would the dye show?
Circle one answer.
- in a network of narrow vessels just under the epithelium
- in the tiny microvilli on the side of the cells facing the food
- in the tall epithelial cells that cover the surface of the villus
- in a single tube in the middle of the villus, closed at its tip
6. identify
Supplement. Which row describes where the microvilli of a villus are, and what they do?
| Row | Where the microvilli are | What they do |
|---|---|---|
| A | on the side of each epithelial cell facing the food | increase the surface area for absorption |
| B | on the side of each epithelial cell facing the food | push the food along the small intestine |
| C | on the side of each epithelial cell facing the capillaries | increase the surface area for absorption |
| D | on the inside wall of the lacteal | carry fatty acids out of the villus |
Circle one answer.
- A
- B
- C
- D
7. identify
Supplement. Put in order what a glucose molecule passes through, from the space inside the small intestine to the blood.
Write the number of each step in order.
- the rest of the epithelial cell
- the blood inside the capillary
- the microvilli on the surface of an epithelial cell
- the wall of a capillary
- First: ______
- Second: ______
- Third: ______
- Last: ______