Introduction
The circulatory system is a closed loop that transports blood gases, nutrients and waste around the body, helps regulate temperature, and protects against injury and disease. This book is going to focus on how blood circulates around the pulmonary (lungs) and systemic (body) pathways to exchange carbon dioxide and oxygen.
Blood that is carrying carbon dioxide is called deoxygenated (meaning without oxygen) and has a bluish tint, so the text will be blue.
Blood that is carrying oxygen (called oxygenated) has more of a red colour, so the text will be red. This colour-coding should help you remember what's happening in each stage.
Since the circulatory system is a closed loop, we could start anywhere and make the full cycle. We're going to start as blood coming back from the body.
Let's start our field trip!
