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प्रश्न
Give scientific reason.
Arteries are thicker than veins.
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उत्तर
- Arteries carry oxygenated blood away from the heart to the body.
- The blood pumped out by the heart is under high pressure and to withstand this pressure arteries are thick-walled.
- Veins carry deoxygenated blood from the body back to the heart.
- They are thin-walled as the blood that flows through veins is under low pressure. Hence, arteries are thicker than veins.
- Veins, on the other hand, have thinner walls and a bigger lumen since they do not need to resist high pressure like arteries.
- Furthermore, because veins convey relatively low-pressure blood, they are frequently fitted with valves to promote unidirectional blood flow towards the heart.
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संबंधित प्रश्न
Put a tick mark (✓) against the correct alternative in the following statement:
Nucleus is absent in
- RBCs
- WBCs
- All blood cells
- Liver cells.
Fill in the blank with suitable word given below:
The colour of a red blood cell is due to _______________.
Name the organ from which oxygenated blood goes into the heart.
The figures given below show diagrammatic cross sections of three kinds of blood vessels.
 |
- Identify the blood vessels A, B and C.
- Name the parts labelled 1-4.
- Mention two structural differences between A and B.
- Name the kinds of blood that flow through A and through B respectively.
- In which one of the vessels referred to in (a) above does the exchange of gases actually take place?
The diagrams given below show the cross-section of two kinds of blood vessels:
(i) Identify the blood vessels A and B. In each case give a reason to support your answer.
(ii) Name the parts numbered 1 and 2.
(iii) When are the sounds “LUBB” and “DUB” produced during a heartbeat?
(iv) Name the blood vessel that
(a) begins and ends in capillaries.
(b) supplies blood to the walls of the heart.
The diagram below represents a certain category of blood vessels showing the role of a special structure in their walls :
(i) Name the kind of blood vessels shown.
(ii) What is the structure shown inside the blood vessels?
(iii) What is the role of these structures?
(iv) Are these structures present in any other kind of blood vessel? If so, name it.
(v) Towards which side of the figure (Top or Bottom) is the heart located?
Long answer question:
How blood is kept moving in the large veins of the legs?
Long answer question:
Describe the histological structure of the artery, vein, and capillary.
Differentiate between an artery and a vein.
______ carry blood to an organ and break up into ______ ending in capillaries.
