Red Blood cells are the body's most common type of blood cell and are extremely important in delivering oxygen to the rest of your body. Red blood cells contain hemoglobin, which is a molecule that can bind to Oxygen. The red blood cells color comes from the presence of iron which helps make up a porphyrin ring inside of hemoglobin.
Oxygen, once it is in the lungs, works in conjunction with carbon dioxide. The lungs work to exchange carbon dioxide and oxygen in the blood. While oxygen is carried to the body's cells, carbon dioxide is carried away from the cells as waste.
In the lungs, oxygen diffuses from the alveola into the blood because the blood has a lower partial pressure than the lung cells. From here, oxygen is picked up by red blood cells that are in the lungs. The red blood cells have cell membranes which are permeable enough so that oxygen can diffuse through them. While oxygen is carried to the tissues, carbon dioxide is realeased from hemoglobin and gets dissolved in blood plasma in the form of bicarbonate.
Oxygen is carried to the body's cells and tissues by Oxygen carrying proteins, such as hemoglobin, and copper containing proteins called haemocyanins. These proteins allow for better diffusion of oxygen into cells, and allows for a larger quantity of oxygen to be diffused.
The role of Oxygen in the body's tissues and cells is extremely important. Approximately, one-third of the oxygen in our body goes right to our brains. Most evidence points to the fact that the more oxygen our brain cells receive, the better our brain functions. The flow of oxygen to the brain activates the brain, particularly areas of the brain that usually die when they don't receive enough blood. Secondly, an increase in oxygen to the brain slows down the normal process of cell death in the brain. So increased oxygen will help to feed those brain cells that get used the least and die off the quickest.
Researchers at John Hopkins have found the the body has a fine tuning system where the cells can dictate how much oxygen goes into cells based on how much is needed. Too little oxygen slows down or shuts down the cells mitochondria, organelles needed to produce energy for the cell and the organism. These cells organelles when functioning correctly react quickly to a drop in cellular oxygen resulting in a finely tuned system within the body, to send more oxygen to the oxygen deprived cells or body organs.
Research has also found that the human body needs ample oxygen in order to optimize our metabolism and to help get rid of waste products. If our body's cells do not get enough oxygen we will be fatigued at the very least, and we may contract diseases(many microorganisms prefer a low/no oxygen atmosphere), and we would also be subject to cancer. It is thought that cells without sufficient oxygen are more likely to turn into cancerous cells, which like an anaerobic (no oxygen) environment.
Oxygen is important to all body systems and cells, from those of the brain, to the nervous system, to the circulatory system and more. It is essential for life itself. Low oxygen levels in cells and tissues are a pretty good indication of some type of underlying disease state.