The Circulatory System
ICSE Class 6 · Biology · Chapter 6
What this chapter covers
- Main parts of the circulatory system
- Process of circulation in the body
- Components of blood
- Heartbeat, pulse and blood pressure
- Keeping the heart healthy
Key points
- The circulatory system carries blood all around the body.
- Its three main parts are the heart, the blood and the blood vessels.
- The heart is a muscular pump in the chest, about the size of a fist.
- Arteries carry blood away from the heart, veins bring it back, and capillaries join the two.
- In the capillaries, oxygen and food pass into the cells, and wastes pass into the blood.
- Blood picks up oxygen and gives out carbon dioxide in the lungs.
- Blood is made of plasma, red blood cells, white blood cells and platelets.
- RBCs carry oxygen, WBCs fight germs and platelets help blood to clot.
- The four main blood groups are A, B, AB and O.
- Healthy adults can donate blood, which blood banks store for patients.
- The pulse is the throb of an artery each time the heart beats.
- Blood pressure is the push of blood on the walls of the arteries.
- Exercise and good food habits keep the heart healthy.
Questions answered
Name the three main parts of the circulatory system.
The heart, the blood and the blood vessels.
Where is the heart found in the body, and how big is it?
It is in the chest, between the two lungs, a little towards the left. It is about the size of a closed fist.
Name the three types of blood vessels. Which type carries blood away from the heart?
Arteries, veins and capillaries. Arteries carry blood away from the heart.
Where in the body do oxygen and food pass out of the blood into the cells?
In the capillaries, whose walls are very thin.
Where does blood that is poor in oxygen go to collect fresh oxygen?
It goes from the heart to the lungs, where it gives out carbon dioxide and takes in oxygen.
Match each part of blood with its job: plasma, RBCs, WBCs, platelets.
Plasma carries digested food, water and wastes; RBCs carry oxygen; WBCs fight germs; platelets help blood to clot.
Name the four main blood groups. Why do doctors check blood groups before giving blood to a patient?
A, B, AB and O. The blood given must suit the blood of the person who receives it.
Ravi counts 20 beats at his wrist in 15 seconds. What is his pulse rate in one minute?
20 × 4 = 80 beats a minute.