A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through ________.

Question

Quizplus · Accepted Answer

Red blood cells leaving the artery would travel through one capillary bed in the thumb to deliver oxygen to cells there. The oxygen-depleted blood would then pass through venules and veins to return to the heart. To reach the left ventricle, it would need to pass through another capillary bed in the lungs where it would be oxygenated before returning to the heart. This means that the red blood cell must pass through a total of two capillary beds - one in the thumb and one in the lungs - to complete its journey.

A Human Red Blood Cell in an Artery of the Left