Circulatory System

body systems · heart · blood vessels · delivery network

Your heart pumps. Your heart is a muscular pump about the size of your fist that beats roughly 100,000 times per day to push blood through your entire body without you even thinking about it.

Blood vessels deliver. Blood travels through tubes called arteries and veins that reach every single cell in your body, delivering oxygen and nutrients while picking up waste to be removed.

Two circuits work together. Your circulatory system has two main loops: one carries blood to your lungs to pick up oxygen, and the other sends that oxygen-rich blood everywhere else in your body.

Continuous round trip. Blood makes the complete journey from your heart to your body and back again in less than a minute, which is why your heart never stops working, even when you sleep.