Which of the following features is not a characteristic of arteries? Arteries
A. possess valves at internals throughout their length.
B. have thick muscular and elastic walls
C. carry blood away from the heart
D. transport oxygenated blood with the exception of the pulmonary artery.
All arteries carry blood away from the heart; while other arteries carry oxygen-rich blood away from the heart to the body cells, pulmonary artery carry deoxygenated blood from the heart to the lungs where they will acquire oxygen through respiration.
Now for the right answer to the above question:
- Option A is correct; arteries do not possess valves, although veins do. Arteries do not need valves because the flow speed and downward gravitational pull of blood from the heart to the body is high enough to prevent backward flow. For veins, they require valves to overcome gravitational backward pull of blood as it travels back to the heart.
- Option B is incorrect; arteries are thick muscular bio-pipes with expansible walls, so it is indeed a characteristic of arteries.
- Of course, arteries do carry blood away from the heart. C is incorrect
- Actually, D is also incorrect; arteries transport oxygen-rich blood from the heart to the body cells with the exception of pulmonary artery which carry oxygen deficient blood to the lungs where it will acquire oxygen through a process of respiration.
You may please note that
- Valves are needed in the veins to allow only forward flow of blood against gravity even as the blood makes its journey back to the heart from the body.
- Arteries do not need valves because the flow of blood is downward, and from the heart to the body, hence, they cannot possibly have bloods flowing backwards.
- Pulmonary veins carry back this blood which has acquired oxygen from the lungs back to the heart.
you may use the questions and answers session to deal further on this topic…
/culled from 2018 JAMB-UTME biology question 14 /