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 nutrients, hormones, 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 handle 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 out to the body via the aorta.
- Large blue vessel on the left side of the heart: Aorta – main artery carrying oxygenated blood from the left ventricle to the body.
- Small pink vessels near the top of the heart: Pulmonary veins – bring oxygenated blood from the lungs to the left atrium.

⚠️ Note: In many diagrams, the pulmonary arteries (going to lungs) are shown as two vessels from the right ventricle, and pulmonary veins (returning from lungs) go into the left atrium.

So here’s how to label the diagram:

| Line / Arrow | Label |
|--------------|-------|
| Top left blue vessel | Superior vena cava |
| Bottom left blue vessel | Inferior vena cava |
| Right top chamber | Right atrium |
| Right bottom chamber | Right ventricle |
| Left top chamber | Left atrium |
| Left bottom chamber | Left ventricle |
| Large blue vessel exiting the left side | Aorta |
| Small pink vessels entering the top left | Pulmonary veins |

✔ Tip: Remember:
- Blue = deoxygenated blood
- Red = oxygenated blood
- Vena cava → right atrium → right ventricle → lungs → pulmonary veins → left atrium → left ventricle → aorta → body

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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. Label the diagram:
From top to bottom, left to right:
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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This worksheet helps reinforce key concepts in the human circulatory system, including blood components, blood vessel types, and heart structure. Let me know if you'd like a printable version or an annotated diagram!