Respiratpry system worksheet - Free Printable

Let's solve each part of this respiratory system worksheet step by step.

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1. Complete the sentences with the words in the box.

Words to use:
respiratory system, breathe, oxygen, carbon dioxide, diaphragm

Sentences:

- The respiratory system helps us breathe.
→ This is the correct pairing. The respiratory system is responsible for breathing.

- When we breathe in, we take in the oxygen our body needs from the air.
→ Oxygen is essential for cellular respiration and is absorbed into the blood in the lungs.

- When we breathe out, we expel the carbon dioxide that our body does not need.
→ Carbon dioxide is a waste product of metabolism and is removed from the body during exhalation.

- The diaphragm is a big muscle that helps us breathe.
→ The diaphragm contracts and relaxes to help draw air into and push it out of the lungs.

✔ Completed Sentences:
- The respiratory system helps us breathe.
- When we breathe in, we take in the oxygen our body needs from the air.
- When we breathe out, we expel the carbon dioxide that our body does not need.
- The diaphragm is a big muscle that helps us breathe.

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2. Label the picture.

Labels available: mouth, lungs, nose, diaphragm, trachea

Looking at the diagram:

- Top left (above the trachea): This is the nose or mouth — but since both are shown, and the topmost structure is the nasal cavity, it’s likely labeled as nose.
- Just below the nose/mouth: trachea (windpipe), which connects the throat to the lungs.
- The large pink structures on either side of the trachea: lungs
- The dome-shaped muscle at the bottom: diaphragm
- The opening at the top (where air enters): mouth (if shown separately) — but often the mouth and nose are both entry points.

Based on typical labeling:

- Top arrow (entrance): nose (or sometimes mouth — if the image shows mouth, but usually nose is higher)
- Vertical tube below nose: trachea
- Two large pink organs: lungs
- Bottom curved muscle: diaphragm
- Top entrance (alternate): If there’s a second arrow pointing to the mouth, then mouth goes there.

But since only five labels are given and five blanks, and based on standard diagrams:

From top to bottom:

1. Nose → Top entry point
2. Mouth → Often shown just below or alongside nose; if there’s an arrow pointing to the mouth, label it
3. Trachea → The long tube going down
4. Lungs → Two large organs on each side
5. Diaphragm → Bottom muscle

But looking at the arrows:

- Arrow pointing to the top of the head area: likely nose
- Arrow pointing to the mouth: mouth
- Arrow pointing to the tube going down: trachea
- Arrows pointing to the two pink organs: lungs
- Arrow pointing to the bottom red muscle: diaphragm

So fill in:

- Top arrow (entry): nose
- Second arrow (just below, possibly mouth): mouth
- Vertical tube: trachea
- Pink organs: lungs
- Bottom muscle: diaphragm

✔ Correct labeling:

- Top (nose): nose
- Below nose (mouth): mouth
- Vertical tube: trachea
- Left and right pink organs: lungs
- Bottom muscle: diaphragm

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3. How do we breathe? Order the sentences.

We need to order these steps logically.

Sentences:

1. The air enters the lungs.
2. Oxygen from the air passes into the circulatory system and the blood carries it to all parts of the body.
3. We breathe out carbon dioxide through our nose and mouth.
4. We breathe in through our nose and mouth.

Logical order:

1. First, we breathe in through nose and mouth → Step 4
2. Then, the air enters the lungs → Step 1
3. Next, oxygen passes into the blood → Step 2
4. Finally, we breathe out carbon dioxide → Step 3

✔ Correct order:

1. We breathe in through our nose and mouth.
2. The air enters the lungs.
3. Oxygen from the air passes into the circulatory system and the blood carries it to all parts of the body.
4. We breathe out carbon dioxide through our nose and mouth.

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✔ Final Answers:

#### 1. Fill in the blanks:
- The respiratory system helps us breathe.
- When we breathe in, we take in the oxygen our body needs from the air.
- When we breathe out, we expel the carbon dioxide that our body does not need.
- The diaphragm is a big muscle that helps us breathe.

#### 2. Label the picture:
- Top (nose): nose
- Below nose (mouth): mouth
- Vertical tube: trachea
- Lungs (left and right): lungs
- Bottom muscle: diaphragm

#### 3. Order the sentences:
1. We breathe in through our nose and mouth.
2. The air enters the lungs.
3. Oxygen from the air passes into the circulatory system and the blood carries it to all parts of the body.
4. We breathe out carbon dioxide through our nose and mouth.

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This completes the worksheet accurately! Let me know if you'd like a printable version or visual explanation.