Heart Circuits

The right and left sides of the heart send blood to different places. I know we discussed this in lab, but I wanted to make sure that you had this information here as well. I have illustrated these two circuits in the figure below.

circuits.jpg (17413 bytes)

You should be able to see that the

	pulmonary circuit goes to and from the lungs (from R Ventricle to L atrium), while the
	systemic circuit carries blood to and from the body tissues (from L Ventricle to R atrium).

The function of each circuit (in an overly simplified way) is:

Pulmonary circuit: to oxygenate the blood

Systemic circuit: to bring oxygen to the body tissues

bloodpath.gif (8816 bytes) Your book summarizes the circuits with this figure to the right. Here, rather than color coding for the systemic or the pulmonary circuits per se, it color codes for whether the blood is oxygenated or not. So, wherever the words are in blue, the blood is deoxygenated. And wherever the words are in pink, the blood is oxygenated. Another way to describe this is that all the steps relating to the right side of the heart involve steps in blue, and all the steps relating to the left side of the heart involve steps in pink.

This picture therefore serves as a nice reminder that all the blood that passes through the right side of the heart is deoxygenated, and all the blood that passes through the left side of the heart is oxygenated.