How is the digestive system connected to the circulatory system?
The digestive system is a body system that takes solid foods an organism eats and processes it to remove essential nutrients used to energize the organism's body. The circulatory system is a body system that pumps blood through a network of blood vessels throughout the organism's body. It is the "superhighway" for delivery to every cell in the organism's body, used to get essential nutrients and fuel in and waste products out. The digestive system takes solid food and reduces it to a soupy, liquid mixture, called chyme. The chyme is introduced into the small intestine, which has lots of finger-like projections called villi . It is here in the small intestine where the villi absorb the glucose, a simple sugar used for energy manufacture in cells, and deliver it to the blood vessels of the circulatory system. The blood of the circulatory system takes the glucose to every cell in the body, along with necessary oxygen supplied by the lungs of the respiratory system. The glucose is combined with the oxygen in a chemical process within the mitochondria of the cell. This process is called cellular respiration and provides energy formation for the cell in the form of an ATP molecule (adenosine triphosphate). Carbon dioxide and water are formed as waste products, which is then delivered back to the blood, which then takes it to the appropriate excretory system organs for disposal.