In addition to oxygen entering the lungs, Vitamin D is produced in the skin by the sun, and molecules are obtained through digestion. Homeostasis and health are constantly maintained by the human digestive system.
Apart from the tube-like digestive pathway from the mouth to the anus, other digestive organs such as the liver, gallbladder, and pancreas play a critical role in keeping the body balanced.
For all body systems to function properly, proteins, carbohydrates, fats, vitamins, and minerals are required. They are provided by the digestive system, which begins at the mouth where food and liquids enter. As soon as the food is chewed and mixed with saliva and enzymes, it passes through the esophagus and enters the stomach where it is churned and mixed with gastric juices.
A number of hormones are produced in the stomach to regulate the digestion and ingestion of food. In the stomach, fat-soluble substances like aspirin enter the bloodstream, while chyme passes into the small intestine. During digestion, bacteria propel food along slowly while further digesting it.
Water, minerals, and vitamins are absorbed by the small intestine from proteins, fats, proteins, and carbohydrates. It is these highly vascularized tissues that transport these nutrients throughout the body. Further breakdown and absorption occurs in the large intestine as well as absorption of any remaining vitamins, electrolytes, and water. Leftover waste is moved to the rectum and eliminated as feces.
To maintain homeostasis in the body, the intestinal bacterial flora is essential. Aside from breaking down food so nutrients can be absorbed, they produce vitamins like biotin and vitamin K and fight harmful bacteria.
An often overlooked function of gut bacteria is immune homeostasis. Bacteria in the gut influence local immunity in the intestines and can also profoundly influence systemic immunity in the body. Lymph nodules in the gut wall called Peyer’s patches secrete interleukin 10 which is an anti-inflammatory and has been shown to stop the spread of tumors in mice.
Also, the intestines are home to a type of immune cell called CD4+ T cells that are part of the adaptive immune system. These T cells differentiate into four other types of T cells including helper T cells. Thus, they help regulate the balance of T cell subtypes in the body which is crucial to good health.
The Digestive Organs
The liver manufactures bile salts that enter the intestines to emulsify fats and make it easier for them to be digested and absorbed. The storage and concentration of bile happens in the gallbladder and it enters the intestines via the bile ducts. Digestive enzymes and bicarbonate are produced in the pancreas.
The bicarbonate helps to neutralize acids in the chyme traveling from the stomach into the small intestine. The raising of the pH also provides the ideal environment for the digestive enzymes to do their work.