Pulmonary vs. Systemic Circulation:
Definitions Explained

The circulatory system consists of two types of circulations: pulmonary vs. systemic.  Let’s see how they differ from each other.

20170427 circulatory system p2
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Pulmonary Circulation:
Whenever blood flows between the heart and the lungs, we call it the pulmonary circulation.  In other words, if the blood’s travel involves the lungs, it is part of the pulmonary circulation.  The purpose of this circulation is to help re-supply the blood with oxygen and take away carbon dioxide from the blood

Systemic Circulation:
Whenever the blood’s travel does NOT include getting oxygen from the lungs, we call it the systemic circulation.  Whether the blood is flowing to the brain, feet, spine, or liver…etc., These are all part of the systemic circulation!  Therefore, the systemic circulation covers a bigger territory than the pulmonary circulation.  The purpose of systemic circulation is to provide every part of the body with oxygen and remove their carbon dioxide.  

Next Generation Science Standards:

MS-LS1-3 Use argument supported by evidence for how the body is a system of interacting subsystems composed of groups of cells.

HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.

HS-LS1-3 Plan and conduct an investigation to provide evidence that feedback mechanisms maintain homeostasis.

What Science Does this Comic Teach?

Unit: Anatomy

⇒Chapter: Circulatory System

⇒Topic: Pulmonary vs. Systemic Circulation

Additional Information


A ventricle is a chamber of the heart that is responsible for pushing blood out of the heart.  The human heart has two ventricles–1 right ventricle and 1 left ventricle.


An atrium is a chamber of the heart that is responsible for receiving blood into the heart.  The human heart has two atria (atria: plural form of atrium)–1 right atrium and 1 left atrium.

Cardiac Muscle

It is one of the 3 major types of muscles: cardiac, skeletal, and smooth.  Cardiac muscle is responsible for the transfer of blood, and it makes up the heart.

Oxygen (O2)

Oxygen is a gas required to most organisms, including humans.  Without oxygen, our tissues will die in a matter of minutes.  We breathe in oxygen.

Carbon Dioxide (CO2)

Carbon dioxide is a gas that is the waste product from metabolic activities.  It has to be removed from our tissues.  We breathe out carbon dioxide.

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