If you clench your hand into a fist, this is approximately the same size as your heart. It is located in the middle of the chest and slightly towards the left. The heart is a large muscular pump ...

labeled diagram of the respiratory system drawing stock illustrations Inner organs - schematic chart with colored organs and... Human gas exchange system vector illustration. Oxygen travel from lungs ...

All blood vessels are specifically structured to perform their function. For example, a capillary is microscopically thin to allow gases to exchange, the arteries are tough and flexible to cope ...