Which diagram shows the human double circulatory system?

• A

• B

• C

• D

How often must a blood cell in the renal artery pass through the heart before it again reaches the renal artery?

• once

• twice

• three times

• four times

The diagram shows a double circulatory system. Which vessels carry oxygenated blood?

• 1 and 2

• 1 and 4

• 2 and 3

• 2 and 4

The diagram shows the circulatory system of a mammal.

What describes the blood in vessels X and Y?

• X: deoxygenated

  Y: deoxygenated

• X: deoxygenated

  Y:oxygenated

• X:oxygenated

  Y: deoxygenated

• X: oxygenated

  Y: oxygenated

Which chamber of the heart has the most muscular wall?

• left atrium

• left ventricle

• right atrium

• right ventricle

The diagram shows a cross-section through a human blood vessel.

Which type of blood vessel does the diagram show?

• an artery

• a capillary

• a vein

• a ventricle

What happens when the left ventricle contracts?

• atrioventricular valves: closed

  semilunar valves: closed

• atrioventricular valves: closed

  semilunar valves: open

• atrioventricular valves: open

  semilunar valves: closed

• atrioventricular valves: open

  semilunar valves: open

The diagram shows the directions of blood flow through a heart.

Which chamber of the heart receives blood directly from the lungs?

• A

• B

• C

• D

What is structure B?

• Left atrium

• Right atrium

• Left ventricle

• Right ventricle

What is structure D?

• Left atrium

• Right atrium

• Left ventricle

• Right ventricle