Pupil sheet · Blood
Blood — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. identify
Two days after losing a lot of blood in an accident, a person's body has replaced the lost plasma, but not yet the cells that carry oxygen. A sample of their blood is spun in a centrifuge. Compared with a sample of healthy blood, which layer of the tube is thinner?
Circle one answer.
- the dark red layer at the bottom
- no layer: all stay the same size
- the pale yellow layer at the top
- the thin pale band in the middle
2. describe
Describe two differences between red blood cells and white blood cells as they look in a stained smear.
(a) First difference
(b) Second difference
3. identify / suggest
Supplement. A pupil looks at a smear of blood from a person who has an infection caused by bacteria. They see far more white cells than usual with a nucleus in several joined lobes and grainy cytoplasm. (a) Identify this kind of white cell. (b) Suggest why the person has more of these cells during the infection.
(a) The kind of white cell
(b) Why there are more of them
4. identify
A blood test shows that a person's plasma contains far more urea than normal. Which organ is most likely not working properly?
Circle one answer.
- the lungs
- the kidneys
- the pancreas
- the small intestine
5. state
Two kinds of cell in the blood defend the body against pathogens. One kind takes pathogens inside itself and digests them; the other kind produces antibodies. (a) State the component of blood that both kinds of cell belong to. (b) State the name of the process in which a cell takes in and digests a pathogen.
(a) The component
(b) The process
6. identify
Supplement. Some days after bacteria got into a person's blood, a test shows plenty of antibodies stuck to the bacteria, and the bacteria are clumped together. But the clumps are still in the blood: they have not been destroyed. Which row gives the kind of cell that is most likely not working, and the reason?
| Row | Cell | Reason |
|---|---|---|
| A | lymphocytes | they produce the antibodies that stick to the bacteria |
| B | phagocytes | they engulf the clumps of bacteria and digest them |
| C | phagocytes | they produce the antibodies that stick to the bacteria |
| D | platelets | they trap the clumps of bacteria in a blood clot |
Circle one answer.
- A
- B
- C
- D
7. state / explain
A pupil writes: "A clot at a cut has one job: it stops the blood running out." State the other role of clotting that the pupil has left out, and explain how the clot does it.
8. predict / explain
Supplement. In a rare condition, a person's plasma contains no fibrinogen. Their platelets are normal. Predict what happens when they cut themselves, and explain your prediction using fibrin.