The circulatory ... lungs. Blood flows through arteries and veins, with valves ensuring unidirectional movement, while capillaries allow nutrient and waste exchange at the cellular level. The ...

The placenta supplied you with oxygen from your mother's blood, so your own lungs were ... of the circulatory system. This short film is from the BBC series, Inside the Human Body.

Your heart first pumps blood to your lungs. Here, the blood picks up oxygen from the air that you have breathed in. The blood (carrying oxygen) then travels back to your heart. The heart gives the ...