Question

28 the diagram shows the internal structure of the human heart.
what is the state of the valves j, k, l and m during ventricular contraction?
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$$\begin{tabular}{|c|c|c|c|c|} \\hline & valve j & valve k & valve l & valve m \\\\ \\hline a & close & close & close & close \\\\ b & close & open & close & open \\\\ c & open & close & close & open \\\\ d & open & close & open & close \\\\ \\hline \\end{tabular}$$

Explanation:

Identify the structures labeled in the diagram

The diagram shows the internal structure of the human heart with four valves labeled:

• Valve J: Semilunar valve (pulmonary valve) on the right side of the heart, leading from the right ventricle to the pulmonary artery.
• Valve K: Atrioventricular valve (tricuspid valve) on the right side, separating the right atrium and right ventricle.
• Valve L: Semilunar valve (aortic valve) on the left side of the heart, leading from the left ventricle to the aorta.
• Valve M: Atrioventricular valve (bicuspid/mitral valve) on the left side, separating the left atrium and left ventricle.

Analyze the cardiac cycle phase

The question asks for the state of these valves during ventricular contraction (ventricular systole):

• During ventricular contraction, the ventricles contract to pump blood out of the heart into the main arteries (pulmonary artery and aorta).
• To prevent the backflow of blood into the atria, the atrioventricular (AV) valves must close.
• To allow blood to flow into the arteries, the semilunar (SL) valves must open.

Determine the state of each valve

Applying these physiological principles to each labeled valve:

• Valve J (semilunar valve): Must be open to allow blood to exit the right ventricle.
• Valve K (atrioventricular valve): Must be close to prevent backflow into the right atrium.
• Valve L (semilunar valve): Must be open to allow blood to exit the left ventricle.
• Valve M (atrioventricular valve): Must be close to prevent backflow into the left atrium.

Match with the given options

Let's check the options in the table:

• A: J (close), K (close), L (close), M (close)
• B: J (close), K (open), L (close), M (open)
• C: J (open), K (close), L (close), M (open)
• D: J (open), K (close), L (open), M (close)

Comparing our determined states:

• Valve J: open
• Valve K: close
• Valve L: open
• Valve M: close

This matches option D perfectly.

Answer:

• (A) valve J: close | valve K: close | valve L: close | valve M: close
• (B) valve J: close | valve K: open | valve L: close | valve M: open
• (C) valve J: open | valve K: close | valve L: close | valve M: open
• (D) valve J: open | valve K: close | valve L: open | valve M: close (Correct answer)