Which one among the following statements about arteries and veins in humans is NOT correct ?
- A.Arteries carry blood away from heart while veins bring blood towards the heart
- B.Pulmonary arteries always carry oxygenated blood while Pulmonary veins always carry deoxygenated blood
- C.Arteries have thicker and more elastic walls compared to veins in general
- D.Arteries do not have valves but veins do have valves
Correct answer
Explanation
The correct answer is B. It reverses the facts: the pulmonary arteries carry deoxygenated blood and the pulmonary veins carry oxygenated blood.
Arteries and veins are named by the direction of flow, not by the oxygen they carry. The pulmonary artery leaves the right ventricle and takes deoxygenated blood to the lungs, while the four pulmonary veins bring freshly oxygenated blood from the lungs back to the left atrium. These are the classic exceptions to the rule that arteries carry oxygen-rich blood. Arteries have thick, elastic, muscular walls because blood leaves the heart under high pressure; veins carry blood at low pressure and have valves that stop it flowing backwards.
A is correct, because arteries carry blood away from the heart and veins bring it back. C is correct, because arterial walls are thicker and more elastic to withstand pressure. D is correct, because valves are a feature of veins, not of arteries.
Exam tip: Pulmonary artery carries deoxygenated blood and the pulmonary vein oxygenated blood, the reverse of the rule.
Practice Questions
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- A.Galileo
- B.Martin Luther
- C.Johannes Kepler
- D.Copernicus
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In 1609 Kepler showed that the planets move around the Sun in elliptical orbits, with the Sun at one focus of the ellipse.
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- B.Urea is produced in blood.
- C.Urea is produced from digestion of starch.
- D.Urea is produced in lung and kidney.
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- A.Condenser-Objective lens-Eyepiece-Body tube
- B.Objective lens-Condenser-Body tube-Eyepiece
- C.Condenser-Objective lens-Body tube-Eyepiece
- D.Eyepiece-Objective lens-Body tube-Mirror
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Read the full explanation →Which one of the following statements regarding haemoglobin is correct?
- A.Haemoglobin present in RBC can carry only oxygen but not carbon dioxide.
- B.Haemoglobin of RBC can carry both oxygen and carbon dioxide.
- C.Haemoglobin of RBC can carry only carbon dioxide.
- D.Haemoglobin is only used for blood clotting and not for carrying gases.
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- A.Histones are proteins that are present in mitochondrial membrane.
- B.Histones are proteins that are present in nucleus in association with DNA.
- C.Histones are proteins associated with lipids in the cytosol.
- D.Histones are proteins associated with carbohydrates in the cytosol.
Show answer
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