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Bicarbonate (HCO − 3) is a vital component of the pH buffering system [3] of the human body (maintaining acid–base homeostasis). 70%–75% of CO 2 in the body is converted into carbonic acid (H 2 CO 3), which is the conjugate acid of HCO − 3 and can quickly turn into it. [citation needed]
The tears are unique among body fluids in that they are exposed to the environment. Much like other body fluids, tear fluid is kept in a tight pH range using the bicarbonate buffer system. [15] The pH of tears shift throughout a waking day, rising "about 0.013 pH units/hour" until a prolonged closed-eye period causes the pH to fall again. [15]
Bicarbonate is useful in neutralizing the acidic gastric acid, allowing for effective enzymic changes. Pancreatic juice secretion is principally regulated by the hormones secretin and cholecystokinin, which are produced by the walls of the duodenum, and by the action of autonomic innervation.
The pancreas further produces large amounts of bicarbonate and secretes bicarbonate through the pancreatic duct to the duodenum to neutralize gastric acid passing into the digestive tract. The secretion is a complex and relatively energetically expensive process.
The pancreas is an organ of the digestive system and endocrine system of vertebrates.In humans, it is located in the abdomen behind the stomach and functions as a gland.The pancreas is a mixed or heterocrine gland, i.e., it has both an endocrine and a digestive exocrine function.
Ductal cells of the pancreas are stimulated by the hormone secretin to produce their bicarbonate-rich secretions, in what is in essence a bio-feedback mechanism; highly acidic stomach chyme entering the duodenum stimulates duodenal cells called "S cells" to produce the hormone secretin and release to the bloodstream. Secretin having entered the ...
Multiple factors affect the rate of bicarbonate secretion: species, cell location in the ductal system, secretory rate, etc. When stimulated, bicarbonate levels can get to 140mM. Due to this, there is a contrast in concentration between the outside and inside environment of ductal cells.
The duodenum also produces the hormone secretin to stimulate the pancreatic secretion of large amounts of sodium bicarbonate, which then raises pH of the chyme to 7. The chyme moves through the jejunum and the ileum , where digestion progresses, and the non-useful portion continues onward into the large intestine .