Connections to Other Systems

     The circulatory system is connected to many other systems. One of them is the respiratory system. The connection between these two systems is at the lungs. The air you take in, eventually goes into a sac-like structure, called alveoli. Surrounding the alveoli are blood vessels filled with deoxygenated blood. What happens is, carbon dioxide from your red blood cells diffuse into the alveoli. In exchange, oxygen from the air diffuses back into the cells for it to be oxygenated again. This course of action is called gas exchange.

Gas exchange

    Another system that has connection to the circulatory is the urinary system(excretory). This happens in the kidneys. Blood from your heart goes to the kidneys through the aorta. The kidneys filter the blood and then sends it back to the heart in a vein called the vena cava.
     The digestive system is the last connection to the circulatory system. In the small intestines, the nutrients are absorbed from the bolus using the villi. The nutrients go into the blood stream and is then, transported around the body.