The Heart, part 1 - Under Pressure: Crash Course A&P #25
Your heart gets a lot of attention from poets, songwriters, and storytellers, but today Hank's gonna tell you how it really works. The heart's ventricles, atria, and valves create a pump that maintains both high and low pressure to circulate blood from the heart to the body through your arteries, and bring it back to the heart through your veins.