GRE Subject Test: Biology : Understanding Circulatory Structures

Study concepts, example questions & explanations for GRE Subject Test: Biology

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Example Questions

Example Question #1 :Understanding Circulatory Structures

Which valve separates the left atrium from the left ventricle?

Possible Answers:

Tricuspid valve

Pulmonary valve

Aortic valve

Mitral valve

Correct answer:

Mitral valve

Explanation:

The heart has four valves, used to prevent backflow of blood during contraction of each chamber. The two atrioventricular valves separate the atria from the ventricles, and the two semilunar valves separate the ventricles from the exiting arteries. The right atrium and ventricle are separated by the tricuspid valve, while the left atrium and ventricle are separated by the bicuspid, or mitral, valve. The aortic semilunar valve separates the aorta from the left ventricle and the pulmonary semilunar valve separates the pulmonary arteries from the right ventricle.

Example Question #2 :Understanding Circulatory Structures

Which of the following blood vessels returns blood to the right atrium of the heart?

Possible Answers:

Carotid artery

Inferior vena cava

Pulmonary vein

Aorta

Correct answer:

Inferior vena cava

Explanation:

Veins are responsible for returning blood to the heart, while arteries take blood away from the heart. The two veins listed are the pulmonary vein and the inferior vena cava. The pulmonary vein returns oxygenated blood to the heart and dumps it into the left atrium. The inferior vena cava returns deoxygenated blood to the heart and dumps it into the right atrium.

Example Question #3 :Circulatory System

Which chamber of the heart pumps blood into the aorta?

Possible Answers:

Left ventricle

Left atrium

Right ventricle

Right atrium

Correct answer:

Left ventricle

Explanation:

The heart has two ventricles which pump blood out of the heart and to either the lungs or the rest of the body. The right ventricle pumps blood into the pulmonary arteries which go to the lungs, and the left ventricle pumps blood into the aorta, which sends blood to the tissues of the body.

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