Blood Flow from Right Ventricle to Lungs

Steps:

• Deoxygenated blood fills the right ventricle from the right atrium via the tricuspid valve.
• Contraction of the right ventricle pushes blood out through the pulmonary semilunar valve.
• This valve prevents backflow and opens into the pulmonary artery.
• Blood then travels to the lungs for oxygenation.

Why D is correct:

• The pulmonary semilunar valve is the outflow valve of the right ventricle, leading directly to the pulmonary artery for pulmonary circulation, as defined in cardiac anatomy.

Why the others are wrong:

• A: Tricuspid valve is inflow to right ventricle; bicuspid (mitral) and left atrium are on the left side for oxygenated blood.
• B: Tricuspid valve allows inflow from right atrium to ventricle, not outflow.
• C: Aortic semilunar valve is for left ventricle outflow to systemic circulation via aorta.

Final answer: D