Guide 03 / six systems
Cardiovascular system
A branching circuit of heart and vessels that keeps every cell supplied, connected, and informed.
The job
Circulates oxygen, nutrients, hormones, and heat while carrying carbon dioxide and other waste away.
Orient yourself
Think of two circuits sharing one pump. The pulmonary circuit sends blood from the right side of the heart to the lungs, while the systemic circuit sends oxygenated blood from the left side to the rest of the body.
Trace a pathway
Follow one red blood cell from the vena cava into the right atrium, through the right ventricle and pulmonary arteries to the lungs, back through the pulmonary veins, then out from the left ventricle through the aorta.
Make the connection
- Capillaries bring blood close enough to cells for diffusion and exchange.
- The respiratory system reloads blood with oxygen and removes carbon dioxide.
- The kidneys adjust blood volume and chemistry, making circulation part of fluid balance.
Close the page
Can you explain it without looking?
Active recall turns recognition into understanding. Answer these prompts in your own words, then return to the guide only for the part you could not reconstruct.
Which side of the heart pumps toward the lungs?
Where does most exchange with tissue occur?
Why are arteries defined by direction rather than oxygen content?