The cardiovascular system includes the heart and the blood vessels, and the respiratory system contains those organs which are responsible for carrying oxygen from the air to the blood stream and expelling the waste product of carbon dioxide. Blood is that sticky, red fluid that circulates throughout our bodies in veins and arteries. The heart pumps oxygen into the blood and collects carbon dioxide from it to be expelled through the lungs. We usually think of respiration as the process of the lungs after air is breathed in through the mouth or nose. The lungs do play a very important role, but every living cell in the body is involved in this process. Respiration is the act of burning energy from oxygen. Breathing is an obvious part of the respiratory passages, but these also involve yawning, sneezing, coughing, hiccups, the power of speech, and the sense of smell. The respiratory flow has been "kidnapped" by the larynx, or voice box, which uses it to create a multiple range of sounds so that humans can communicate vocally. These systems' tasks include organs which take up space in the face and neck and most of the chest. The cardiovascular and respiratory systems are basic to life and breathing, like the beat of one's heart, is an automatic function which is controlled by the brain.

It is interesting to note that when tissues and organs are deprived of oxygen, blood will turn blue? We all have heard this cliche before ... "I'm going to hold my breath until I turn blue."