The rectum is a part of the large intestine, which can be divided into ascending colon, transverse colon, descending colon, sigmoid colon and rectum according to its anatomical location. Its physiological function is mainly to reabsorb water and certain minerals in feces to avoid loss, while storing and transferring feces, which is important for maintaining normal physiological function of the body. The rectum belongs to the large intestine in a broad sense, but its physiological function focuses on the storage of feces, and its reabsorption function is not as important as that of the other large intestine. When the colon needs to be surgically removed due to certain diseases, it will cause its physiological dysfunction, which will result in changes in stool characteristics. For example, the frequency of stools increases or the stools are not shaped, which can lead to water and electrolyte disorders in severe cases, thus causing serious clinical complications. In conclusion, all parts of the large intestine work together to maintain the normal physiological function of the body.