Year 8 Science · Unit 1 · Lesson 3
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank. Each word is used once at most. Two words will not be used.
An organ system is a group of working together to carry out one major . The heart, blood vessels and blood are the of the system, which transports substances around the body. The lungs and air passages make up the system, whose major job is gas exchange.
Sort it
Write each component in the organ system it belongs to. Each box gets exactly three.
Circulatory
Respiratory
Digestive
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. Blood is a part of the circulatory system, not just a liquid inside it.
Correct it:
2. The organs in one system usually each do a different job.
Correct it:
3. A heart with no blood vessels could still transport substances around the body.
Correct it:
4. Living things have several organ systems because they need several different major jobs done.
Correct it:
5. The major job of the digestive system is gas exchange.
Correct it:
Read the data
Where does the blood go?
Blood leaving the heart is shared out between the organs. Table 1 shows roughly how it is split in an adult sitting still.
| Part of the body | Share of the blood (%) |
|---|---|
| Stomach, intestines and liver | 27 |
| Kidneys | 22 |
| Muscles of the arms, legs and body | 15 |
| Brain | 14 |
| Skin | 6 |
| Heart muscle | 4 |
| All other parts | 12 |
Source: rounded from a human physiology textbook. The shares shift during exercise and after a meal.
1. Which part of the body receives the largest share of the blood?
2. How many times bigger is the kidneys’ share than the heart muscle’s share?
Answer times
3. The stomach and intestines belong to the digestive system. Suggest why the blood flowing through them is important for the digestive system to finish its job.
4. No row in Table 1 is zero. Explain what this shows about how much the body’s other systems rely on the circulatory system.
5. Jess says: “If I had a working heart, I would have a working circulatory system.” Explain what Jess has missed. Name the part that pumps, the parts that carry the blood, and the part that delivers oxygen and food. Then state the overall job they share, and what would fail if one part were absent.
Fill the gap
organs; function; components; circulatory; respiratory. Not used: tissues, cells.
Sort it
Circulatory: heart, blood vessels, blood. Respiratory: nose, trachea (windpipe), lungs. Digestive: stomach, small intestine, large intestine.
True or false
1. True. 2. True. 3. False: without blood vessels, the pumped blood cannot reach the body; the heart, vessels and blood must work together. 4. True. 5. False: the digestive system breaks down food and absorbs useful substances; gas exchange is the job of the respiratory system.
Read the data
1. The stomach, intestines and liver (27%). [1 mark]
2. 22 ÷ 4 = 5.5 times. [1 mark]
3. The digestive system breaks food down into useful substances, and these are absorbed into the blood in the intestines. The blood then carries them away to cells all over the body, so without the blood the absorbed food could not reach the cells. [2 marks: 1 absorbed into the blood, 1 carried to the body’s cells]
4. Every organ, in every system, receives blood, because its cells need oxygen and food delivered and wastes taken away. Only the circulatory system transports these substances, so if it stopped, the organs of the other systems would stop working. [2 marks: 1 what blood brings to every organ, 1 conclusion about dependence]
Show What You Know
5. Marking guide: 1 each for the heart (pumps blood), blood vessels (carry blood through the body) and blood (transports substances such as oxygen and food); 1 for the overall function (the system transports substances around the body); 1 for a correct “missing component” example (without vessels, the pumped blood has nowhere to go; without blood, there is nothing to carry the substances; without the heart, the blood does not move). Model answer: The heart is only one component. It pumps blood, but blood vessels are needed to carry the blood to every part of the body, and the blood itself transports oxygen and food. The three work together so the system can transport substances around the body. If the blood vessels were missing, the heart could pump but nothing would reach the cells. [5 marks]
Common error to watch for: describing the circulatory system as “important” without naming components or roles. Push students to write component → role → function.