The Circulatory System worksheet with questions and a labeled diagram of the heart.
Diagram of the human circulatory system showing the heart with labeled parts including the left and right atria and ventricles, and blood flow directions to and from the lungs, upper body, and lower body.
JPG
821×1169
89.3 KB
Free · Personal Use
Quality Assured by Worksheets Library Team
Reviewed for educational accuracy and age-appropriateness
ID: #935195
⭐
Show Answer Key & Explanations
Step-by-step solution for: Circulatory System answer sheet - ESL worksheet by dianemperrino
▼
Show Answer Key & Explanations
Step-by-step solution for: Circulatory System answer sheet - ESL worksheet by dianemperrino
The image you've uploaded is a worksheet titled "The Circulatory System", which contains questions and a diagram of the human heart. Let's go through each question, verify the answers, and explain them clearly.
---
Answer: 4–5 litres
Explanation:
An average adult has about 5 liters of blood (though it can vary slightly depending on size and sex). This volume helps maintain circulation, transport oxygen, nutrients, hormones, and waste products throughout the body.
---
Answer: The Heart
Explanation:
The heart is a muscular organ that acts as a pump. It contracts rhythmically to push blood through the circulatory system via arteries, capillaries, and veins.
---
Answer: Red
Explanation:
Oxygen-rich blood is bright red because hemoglobin in red blood cells binds with oxygen, giving it a vibrant red color. This blood is carried by arteries from the lungs to the body.
---
Answer: Blue
Explanation:
This is a common misconception. In reality, oxygen-poor blood is dark red, not blue. However, in diagrams, veins are often shown in blue to distinguish them from arteries (which are red), even though blood in veins is still red — just darker due to less oxygen.
> 🔍 Clarification: Blood is never truly blue. The "blue" color in diagrams is symbolic, representing deoxygenated blood.
---
"Blood flowing away from the heart travels in arteries. Blood flowing towards the heart travels in veins."
Answer: Correct as written.
Explanation:
- Arteries carry blood away from the heart.
- Veins carry blood toward the heart.
> Note: The pulmonary artery carries deoxygenated blood from the heart to the lungs, and the pulmonary vein carries oxygenated blood from the lungs back to the heart — exceptions to the general rule.
---
Answer: About 8 million
Explanation:
Approximately 8 million red blood cells die every second in the human body. They are continuously replaced by new ones produced in the bone marrow. This high turnover rate ensures efficient oxygen delivery.
---
Answer: 4 chambers
- Left Atrium
- Left Ventricle
- Right Atrium
- Right Ventricle
Explanation:
The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
- The right side receives deoxygenated blood from the body and pumps it to the lungs.
- The left side receives oxygenated blood from the lungs and pumps it to the rest of the body.
---
The diagram already includes labels:
- Right Atrium
- Right Ventricle
- Left Atrium
- Left Ventricle
- Arrows showing flow:
- From upper/lower body → Right Atrium
- To lungs → Pulmonary arteries
- From lungs → Left Atrium
- To upper/lower body → Aorta
Correct labeling explanation:
- Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.
- Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary arteries.
- Left Atrium: Receives oxygenated blood from the lungs via the pulmonary veins.
- Left Ventricle: Pumps oxygenated blood to the body via the aorta.
✔ The diagram is correctly labeled as per standard anatomy.
---
| Concept | Detail |
|--------|--------|
| Blood Volume | ~4–5 liters |
| Organ Pumping Blood | Heart |
| Oxygen-Rich Blood Color | Bright red |
| Oxygen-Poor Blood Color | Dark red (often shown as blue in diagrams) |
| Blood Flow Direction | Arteries = away from heart; Veins = toward heart |
| RBC Death Rate | ~8 million per second |
| Heart Chambers | 4: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle |
---
- All answers provided in the worksheet are correct based on standard biology knowledge.
- The only nuance is Question 4: While the answer says "Blue", it's important to clarify that blood is never actually blue — it’s a visual convention in diagrams.
- The heart diagram is accurately labeled and shows proper blood flow paths.
Let me know if you'd like a printable version or want to turn this into a quiz!
---
✔ Question 1: How much blood does an average person have?
Answer: 4–5 litres
Explanation:
An average adult has about 5 liters of blood (though it can vary slightly depending on size and sex). This volume helps maintain circulation, transport oxygen, nutrients, hormones, and waste products throughout the body.
---
✔ Question 2: What is the name of the organ that pushes the blood around the body?
Answer: The Heart
Explanation:
The heart is a muscular organ that acts as a pump. It contracts rhythmically to push blood through the circulatory system via arteries, capillaries, and veins.
---
✔ Question 3: What colour is oxygen-rich blood?
Answer: Red
Explanation:
Oxygen-rich blood is bright red because hemoglobin in red blood cells binds with oxygen, giving it a vibrant red color. This blood is carried by arteries from the lungs to the body.
---
✔ Question 4: What colour is oxygen-poor blood?
Answer: Blue
Explanation:
This is a common misconception. In reality, oxygen-poor blood is dark red, not blue. However, in diagrams, veins are often shown in blue to distinguish them from arteries (which are red), even though blood in veins is still red — just darker due to less oxygen.
> 🔍 Clarification: Blood is never truly blue. The "blue" color in diagrams is symbolic, representing deoxygenated blood.
---
✔ Question 5: Fill in the blanks:
"Blood flowing away from the heart travels in arteries. Blood flowing towards the heart travels in veins."
Answer: Correct as written.
Explanation:
- Arteries carry blood away from the heart.
- Veins carry blood toward the heart.
> Note: The pulmonary artery carries deoxygenated blood from the heart to the lungs, and the pulmonary vein carries oxygenated blood from the lungs back to the heart — exceptions to the general rule.
---
✔ Question 6: How many blood cells die in the human body each second?
Answer: About 8 million
Explanation:
Approximately 8 million red blood cells die every second in the human body. They are continuously replaced by new ones produced in the bone marrow. This high turnover rate ensures efficient oxygen delivery.
---
✔ Question 7: How many chambers in the heart? Name them.
Answer: 4 chambers
- Left Atrium
- Left Ventricle
- Right Atrium
- Right Ventricle
Explanation:
The heart has four chambers: two atria (upper chambers) and two ventricles (lower chambers).
- The right side receives deoxygenated blood from the body and pumps it to the lungs.
- The left side receives oxygenated blood from the lungs and pumps it to the rest of the body.
---
✔ Question 8: Label this diagram of a heart
The diagram already includes labels:
- Right Atrium
- Right Ventricle
- Left Atrium
- Left Ventricle
- Arrows showing flow:
- From upper/lower body → Right Atrium
- To lungs → Pulmonary arteries
- From lungs → Left Atrium
- To upper/lower body → Aorta
Correct labeling explanation:
- Right Atrium: Receives deoxygenated blood from the body via the superior and inferior vena cava.
- Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary arteries.
- Left Atrium: Receives oxygenated blood from the lungs via the pulmonary veins.
- Left Ventricle: Pumps oxygenated blood to the body via the aorta.
✔ The diagram is correctly labeled as per standard anatomy.
---
📌 Summary of Key Concepts:
| Concept | Detail |
|--------|--------|
| Blood Volume | ~4–5 liters |
| Organ Pumping Blood | Heart |
| Oxygen-Rich Blood Color | Bright red |
| Oxygen-Poor Blood Color | Dark red (often shown as blue in diagrams) |
| Blood Flow Direction | Arteries = away from heart; Veins = toward heart |
| RBC Death Rate | ~8 million per second |
| Heart Chambers | 4: Right Atrium, Right Ventricle, Left Atrium, Left Ventricle |
---
✔ Final Notes:
- All answers provided in the worksheet are correct based on standard biology knowledge.
- The only nuance is Question 4: While the answer says "Blue", it's important to clarify that blood is never actually blue — it’s a visual convention in diagrams.
- The heart diagram is accurately labeled and shows proper blood flow paths.
Let me know if you'd like a printable version or want to turn this into a quiz!
Parent Tip: Review the logic above to help your child master the concept of human circulatory system worksheet.
