Year 8 Science · Unit 1 · Lesson 9
Apply Worksheet
Learning Goals
Order the steps
Number the steps from 1 to 4 to show the correct order of how the circulatory system transports substances around the body. Step 1 = what happens first.
| Order | Step |
|---|---|
| Blood vessels carry blood through the body to reach different tissues and organs | |
| Substances (such as oxygen and nutrients) are delivered to body cells and wastes are collected | |
| Blood transports the substances as it moves through the vessels | |
| The heart pumps blood |
Real-world context
Nurses at the Royal Children's Hospital in Melbourne often check a patient's pulse rate (heart rate). A faster heart rate means the heart is pumping blood more quickly around the body. During illness, fever, or exercise, the body's cells need substances delivered faster than at rest. The circulatory system responds by increasing the rate at which blood is pumped.
(a) Using the three components of the circulatory system, explain how a faster heart rate helps cells get what they need more quickly.
(b) If the blood vessels were blocked and blood could not flow, the heart would still be pumping. Explain why this situation would still cause cells to be deprived of what they need, even though the heart is working.
1. A student says: "The most important part of the circulatory system is the heart, because without it nothing works." Do you agree? Explain why a systems view, that considers all three components, gives a more complete scientific explanation.
Wrap Up
In one sentence, what was the main idea of this lesson?