The Function of the Heart

The heart is a vital organ responsible for pumping blood throughout the body. It consists of four chambers: two atria (left and right) and two ventricles (left and right). The heart muscles contract and relax in a coordinated manner to ensure efficient blood circulation.

The Contraction of Heart Muscles

When the muscles of the heart contract, the chambers of the heart undergo specific actions that allow for the circulation of blood. The contraction of the heart muscles is known as systole, while relaxation is called diastole.

Function of the Right Ventricle

The right ventricle of the heart receives deoxygenated blood from the right atrium. This blood has already circulated through the body and is low in oxygen content. When the right ventricle contracts, it pumps this deoxygenated blood into the pulmonary artery, which carries it to the lungs for oxygenation.

Function of the Lungs

In the lungs, oxygen is exchanged for carbon dioxide through the process of respiration. The oxygen-rich blood then returns to the heart via the pulmonary veins, specifically into the left atrium.

Function of the Left Ventricle

The left atrium contracts, pushing the oxygenated blood into the left ventricle. The left ventricle is the largest and strongest chamber of the heart. When it contracts, it pumps the oxygenated blood out of the heart and into the aorta, the main artery of the body. From the aorta, the oxygenated blood is distributed to various organs and tissues throughout the body.

Answer Explanation

The correct answer to the question is option C: "blood is pumped from the right ventricle into the lungs." When the muscles of the heart contract, blood is pumped from the right ventricle into the lungs. This action allows for the oxygenation of the blood and the removal of carbon dioxide waste. The oxygen-rich blood is then returned to the heart so that it can be pumped to the rest of the body. Therefore, options A and B are incorrect as they do not accurately describe the flow of blood during heart muscle contraction.

Answer:
The correct answer is C: blood is pumped from the right ventricle into the lungs.
When the muscles of the heart contract, it goes through a series of events called the cardiac cycle. During this cycle, the heart contracts and relaxes to pump blood throughout the body. Here is a detailed explanation of what happens when the muscles of the heart contract:
1. Contraction of the atria: The muscles of the atria, the upper chambers of the heart, contract first. This contraction pushes the blood into the ventricles.
2. Contraction of the ventricles: After the atria contract, the muscles of the ventricles, the lower chambers of the heart, contract. This contraction is responsible for pumping the blood out of the heart.
3. Closure of the atrioventricular valves: As the ventricles contract, the atrioventricular valves, which separate the atria from the ventricles, close. This prevents the backflow of blood into the atria.
4. Opening of the semilunar valves: Simultaneously, the contraction of the ventricles causes the semilunar valves, which separate the ventricles from the blood vessels, to open. This allows the blood to be pumped out of the heart.
5. Blood flow to the lungs: When the ventricles contract, the right ventricle pumps deoxygenated blood into the pulmonary artery. The pulmonary artery carries the blood to the lungs, where it picks up oxygen and gets rid of carbon dioxide.
Therefore, when the muscles of the heart contract, blood is pumped from the right ventricle into the lungs (Option C).