Question Video: Recalling the Role of Valves in the Heart | Nagwa Question Video: Recalling the Role of Valves in the Heart | Nagwa

Question Video: Recalling the Role of Valves in the Heart Biology • Second Year of Secondary School

What structures within the heart control blood flow from the atria into the ventricles?

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Video Transcript

What structures within the heart control blood flow from the atria into the ventricles? (A) Capillaries, (B) nerves, (C) stents, (D) valves, or (E) arteries.

To answer this question, let’s first discuss what atria and ventricles are by looking at a diagram of the heart. Numbers one and two on our diagram refer to the right and left atria, or singular atrium. These are the chambers of the heart that receive blood from veins. Blood is then pumped from the atria to the ventricles. The right ventricle is labeled as three and the left ventricle as four in our diagram.

To be efficient, the heart needs structures which ensure the blood flows through the heart in one direction only. So when the heart contracts, the blood should flow out of the arteries and not back into the atria. When the heart relaxes, the blood which is in the arteries should not flow back into the heart. Structures called valves prevent the backflow of blood. The semilunar valves prevent the backflow of blood from the arteries into the heart.

The bicuspid valve is situated between the left atrium and ventricle and prevents the backflow of blood in these chambers, while the tricuspid valve is located between the right atrium and ventricle, preventing backflow of blood in these chambers. The bicuspid valve has two flaps, and the tricuspid valve has three. These flaps are attached to tendons, which prevent the valves from turning inside out by mistake.

We now have enough information to answer our question. The structures within the heart that control blood flow from the atria into the ventricles are named in answer choice (D), valves.

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