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Correct Answer: tricuspid valve, pulmonary valve, bicuspid valve, and aortic valve.
to understand the correct circuit through which a blood cell passes through the heart's valves after returning via the vena cava, it's essential to grasp the basic anatomy and flow of blood through the heart. here's an expanded explanation:
the heart is divided into four chambers: the right atrium, the right ventricle, the left atrium, and the left ventricle. valves between these chambers ensure that blood flows in the correct direction. blood returning from the body via the vena cava is deoxygenated and enters the heart through the right atrium.
once in the right atrium, the first valve that the blood encounters is the tricuspid valve. this valve separates the right atrium and the right ventricle. its primary function is to prevent the backflow of blood into the right atrium when the right ventricle contracts to pump blood to the lungs.
after passing through the tricuspid valve, the blood moves into the right ventricle. from here, it is pumped through the pulmonary valve into the pulmonary artery. the pulmonary valve is critical as it prevents the backflow of blood from the pulmonary artery into the right ventricle during relaxation of the heart muscle. the blood then travels to the lungs via the pulmonary artery where it becomes oxygenated.
oxygenated blood returns to the heart from the lungs via the pulmonary veins, entering the left atrium. it then passes through the bicuspid valve, also known as the mitral valve, which lies between the left atrium and the left ventricle. this valve ensures that oxygenated blood flows into the left ventricle without leaking back into the left atrium when the ventricle contracts.
finally, the blood leaves the left ventricle passing through the aortic valve into the aorta, the body's main artery. the aortic valve's role is crucial in preventing blood from flowing back into the left ventricle from the aorta as the heart relaxes.
thus, the correct sequence of valves that blood passes through after returning from the vena cava is: the tricuspid valve, the pulmonary valve, the bicuspid (mitral) valve, and the aortic valve. this pathway is crucial for the circulation of blood, ensuring it moves efficiently and is properly oxygenated before being distributed throughout the body.
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