The Circulatory System Worksheet | PDF - Free Printable

Let's solve each part of this GCSE Biology: Circulatory System Worksheet step by step and explain the answers.

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1. Match the components of blood to their functions

We need to draw lines between the blood components on the left and their correct functions on the right.

| Blood Component | Function |
|---------------------|--------|
| Red blood cell | → carry oxygen
| Platelets | → causes the blood to clot to prevent loss
| White blood cell| → fight invading pathogens
| Plasma | → medium in which substances float or dissolve

✔ Explanation:
- Red blood cells (RBCs) contain hemoglobin, which binds to oxygen in the lungs and carries it to tissues.
- Platelets are fragments of cells that help form clots at injury sites to stop bleeding.
- White blood cells (WBCs) are part of the immune system and defend the body against infections.
- Plasma is the liquid component of blood where cells and other substances (like hormones, nutrients, waste) are suspended.

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2. Fill in the gaps in the passage below

> The circulatory system transports substances around the body.
> Blood vessels called arteries have thick muscular walls and transport blood away from the heart to other tissues and organs.
> Blood is taken from tissues to the heart by blood vessels called veins, which have larger lumens and thin walls.
> Capillaries are small vessels which exchange materials with tissues.

✔ Explanation:
- The circulatory system transports oxygen, nutrients, hormones, and waste products.
- Arteries carry blood *away* from the heart; they have thick walls to withstand high pressure.
- Veins carry blood *back* to the heart; they have thinner walls and valves to prevent backflow.
- Capillaries are tiny vessels where gas and nutrient exchange occurs between blood and tissues.

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3. a) Label the diagram below

Here’s a breakdown of the heart diagram (based on standard human heart anatomy):

From the image:
- Top left blue vessel: Superior vena cava – brings deoxygenated blood from the upper body to the right atrium.
- Bottom left blue vessel: Inferior vena cava – brings deoxygenated blood from the lower body to the right atrium.
- Right top chamber: Right atrium – receives deoxygenated blood from the vena cavae.
- Right bottom chamber: Right ventricle – pumps deoxygenated blood to the lungs via pulmonary artery.
- Pulmonary artery – exits the right ventricle (not labeled directly but implied).
- Left top chamber: Left atrium – receives oxygenated blood from the lungs via pulmonary veins.
- Left bottom chamber: Left ventricle – pumps oxygenated blood to the body via the aorta.
- Large red vessel on top: Aorta – main artery carrying oxygenated blood from the left ventricle.
- Small pink vessels entering left atrium: Pulmonary veins – carry oxygenated blood from lungs to the left atrium.

So, the labels should be:

1. Superior vena cava
2. Inferior vena cava
3. Right atrium
4. Right ventricle
5. Left atrium
6. Left ventricle
7. Aorta
8. Pulmonary veins

⚠️ Note: Depending on how many lines there are, you might need to adjust. But typically, these are the key structures shown.

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✔ Final Answer Summary

#### 1. Matching:
- Red blood cell → carry oxygen
- Platelets → causes the blood to clot to prevent loss
- White blood cell → fight invading pathogens
- Plasma → medium in which substances float or dissolve

#### 2. Fill in the blanks:
- The circulatory system transports substances around the body.
- Blood vessels called arteries have thick muscular walls and transport blood away from the heart to other tissues and organs.
- Blood is taken from tissues to the heart by blood vessels called veins, which have larger lumens and thin walls.
- Capillaries are small vessels which exchange materials with tissues.

#### 3. a) Labels (from diagram):
(From top to bottom, left to right — based on typical layout)
1. Superior vena cava
2. Inferior vena cava
3. Right atrium
4. Right ventricle
5. Left atrium
6. Left ventricle
7. Aorta
8. Pulmonary veins

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