The digestive system is a complex network of organs and tissues that work together to break down food and absorb nutrients. It consists of the gastrointestinal tract, also known as the digestive tract or GI tract, and the liver, pancreas, and gall bladder. The gastrointestinal tract is a series of hollow organs connected in a long, winding tube from the mouth to the anus. The hollow organs that make up the GI tract are the mouth, esophagus, stomach, small intestine, large intestine, and anus.
The liver, pancreas, and gall bladder are the solid organs of the digestive system. The digestive system includes the digestive tract and its accessory organs, which process food into molecules that can be absorbed and used by the body's cells. Food is broken down gradually until the molecules are small enough to be absorbed and waste products are eliminated. The tongue and teeth are accessory structures located in the mouth.
The salivary glands, liver, gallbladder, and pancreas are the main accessory organs that play a role in digestion. These organs secrete fluids into the digestive tract. Nutrient-rich blood goes directly to the liver for processing. The liver filters out harmful substances or wastes and converts some of the waste into more bile.
It also helps determine how many nutrients will go to the rest of the body and how many will remain stored. For instance, it stores certain vitamins and a type of sugar that the body uses for energy. Nerves connect the central nervous system, brain, and spinal cord to the digestive system and control some digestive functions. The cecum is an organ with pouches at the beginning of the large intestine that contains many microorganisms necessary for digesting plant materials.
When digesting proteins and some fats, the stomach lining must be protected from being digested by pepsin. Working together, nerves, hormones, bacteria, blood, and organs in the digestive system digest the foods and liquids we consume every day. The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine and push it forward for further digestion. Animals have developed different types of digestive systems to help digest different foods they consume.
Humans have an omnivorous digestive system while animals such as cows have a ruminant digestive system. Humans have an omnivorous digestive system which means they can eat both plant-based foods as well as meat-based foods. The human digestive system is composed of several organs including a stomach, small intestine, large intestine, liver, gallbladder, pancreas, and esophagus. These organs work together to break down food into smaller molecules that can be absorbed by our bodies for energy and nutrition.Ruminant animals such as cows have a four-chambered stomach which allows them to digest plant-based foods more efficiently than humans can.
The four chambers are called rumen, reticulum, omasum, and abomasum. The rumen is where forage is fermented and digested by microorganisms while other chambers help break down plant material further before it is passed on to other parts of their digestive system.The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) and other components of the National Institutes of Health (NIH) conduct research on many diseases and conditions related to digestion.