How do veins ensure that blood flows in one direction in human body?
Show answer & explanation
Correct answer: D
Explanation
Correct Answer:
Option 4: By means of valves
Explanation:
In the human body, veins contain valves that serve to maintain blood flow in a single direction. These valves prevent blood from flowing backward. As blood moves toward the heart, the valves open; they close when the blood attempts to flow back. This mechanism is particularly crucial in the veins of the legs, where blood must be pumped upward against the force of gravity. Working in conjunction with muscular contractions, this system regulates blood flow.
Additional Facts:
Option 1: Thick walls are a characteristic feature of arteries.
Option 2: Low blood pressure is not the cause.
Option 3: Veins do not undergo contractions.
Option 4: Correct answer.
Potential Questions for Upcoming Exams:
Question: What is the function of arteries?
Answer: To carry blood away from the heart.
Question: What is the function of veins?
Answer: To carry blood back to the heart.
Question: How many chambers does the heart have?
Answer: 4
Question: What causes the red color of blood?
Answer: Hemoglobin