what is the gut

The gut refers to the gastrointestinal (GI) system, which is the tract or passageway of the digestive system that leads from the mouth to the anus. It includes all the major organs of the digestive system, such as the mouth, esophagus, stomach, small intestine, large intestine, and anus. The gut is an endoderm-derived structure that begins to form at approximately the sixteenth day of human development, when the embryo begins to fold ventrally in two directions, resulting in the primitive gut. During fetal life, the primitive gut is gradually patterned into three segments: foregut, midgut, and hindgut. The gut breaks down the foods we eat and absorbs nutrients that support our body’s functions. The gut microbiome, which refers to the bacteria and other micro-organisms in our gut, helps to break down food and turn it into nutrients our body can use. The gut microbiome interacts with many of our body systems and assists with many body functions, such as regulating aspects of our metabolism, including blood sugar, hunger, and satiety. The gut is also known as the enteric nervous system (ENS), which is two thin layers of more than 100 million nerve cells lining our gastrointestinal tract from esophagus to rectum. The ENS is sometimes referred to as the "second brain" because it can affect our digestion, mood, health, and even the way we think.