Page 101 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

Ans. (a) Arteries and veins

Arteries Veins
These blood vessels carry oxygenated These blood vessels carry deoxygenated

blood from the heart to all the parts of blood from the organs to the heart.
the body.
Arteries have thick, elastic and muscular Veins have thin, non-elastic and less

walls. muscular walls.
They are narrow so that the blood can They are slightly wider than the

flow quickly through them. arteries.
They do not contain valves. They contain valves that prevent blood
from flowing in the opposite direction.
The blood flows with jerks under The blood flows smoothly under very

pressure. little pressure.

(b) RBC and WBC
RBC WBC
1. They help transport oxygen & carbon 1. They help fight infections &
dioxide carbon dioxide. provide immunity.

2. They are red in colour due to the 2. They are colourless.
presence of haemoglobin.
3. They are approximately 4.5 – 5.5 3. They are approximately 4000 –

million per microlitre of blood. 11,000 per microlitre of blood.
4. They contain haemoglobin. 4. They do not contain heamoglobin.

(c) Atrium and ventricle
Atrium Ventride

1. They are the upper chambers of the 1. They are the lower chambers of
heart. the heart.
2. Right atrium receives blood from the 2. Right ventricle pumps blood to the

body whereas left atrium receive lungs whereas left ventricle pumps
blood from the lungs. blood to the rest of the body.
3. It has thinner walls. 3. It has thicker walls.

4. They collect blood returning to the 4. They pump blood away from the
heart. heart.

5. Right atrium contains deoxygenated 5. Right ventricle contains
blood whereas left atrium contains deoxygenated blood whereas left
oxygenated blood. ventricle contains oxygenated

blood.

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