Blood is the life line of the human body. The functions that it performs are extremely critical to the well-being of the body. This essential fluid transports oxygen and various nutrients to every cell in the human body. It also carries carbon dioxide, ammonia, uric acid and other waste products, from the cells to the excretory organs in order to be thrown out of the body. Other than these vital functions, blood works to regulate our body temperature, maintaining it at a comfortably constant value. It is also fundamental to keeping our immune system in clock-work functioning order.