Minerals in the diet should be absorbed by all the epithelial cells that direct the gastrointestinal tract (GI) to pass into the bloodstream for usage by the tissues. From any part of the GI tract; the mineral can be absorbed. However, the small intestine is where the majority of mineral absorption takes place. The small intestine is a section of the digestive tract located between the stomach and the large intestine, and it is where the majority of food is processed. One of the principal functions of the small intestine is to absorb the minerals and nutrients present in the food. The digested nutrients enter the blood vessels in the intestinal wall through the diffusion process. The mucosa is the inner wall of the small intestine and is lined with the superficial columnar epithelial tissue.
Generally, the absorption of minerals happens in proportion to the diet intake, except for calcium and iron absorption, which are regulated as per the body’s needs. Two distinct mechanisms are followed to absorb calcium from the intestinal lumen. Anatomically, the mucosa is enclosed by folds or wrinkles known as plicae circulares; these are the permanent structures in the organ’s wall. From the plicae circulares, tiny finger-like tissue projections are presently known as villi. The individual cells of the epithelia also have these projections and are known as microvilli. Every villus has a capillary network, and fine lymphatic vessels termed lacteals near its surface. The epithelial cells present in the villi transfer nutrients to these capillaries (carbohydrates and amino acids) and lacteals from the intestinal lumen. The absorbed substances are transferred through the blood vessels to various organs of the body, where they are utilized to make complex substances like proteins that the body needs. The unabsorbed and undigested foods that remain pass into the large intestine.
Hormonal system regulating GI tract for minerals absorption
Food consumption, digestion, and mineral and nutrient absorption through the GI tract wall are vital physiological functions for living vertebrates. The GI system is where food enters the body, and it is well recognized that GI motility influences dietary behavior and helps maintain energy balance. Invertebrates’ GI motility is controlled by muscular contractions modulated by external parasympathetic and sympathetic neurons, innate enteric sensory and motor neurons, and other GI hormones. Hormone molecules use the bloodstream to carry data from one cell to another by stimulating particular receptors on target cells. Several gastrointestinal hormones have been identified, including peptide YY, secretin, gastrin, neurotensin, gastrin-releasing peptide, ghrelin, cholecystokinin, somatostatin, and motilin. The GI hormones are made in the GI epithelium’s specialized enteroendocrine cells. They affect the vagal nerve’s afferent terminals, as well as other digestive system organs, cells, and afferent terminals.
