So bile is secreted into the GI tract. Now we talked about what happens to fats once they're absorbed in the ileum when we talked about the small intestine.
But what happens to our bile salts? Well the bile salts, after they've been absorbed in the ileum, are actually gonna circulate right on back to the liver to undergo this process all over again. So if we were to review all the different pit stops that our bile takes in this process. Number one is that bile is made in the liver. Then once it's made number two it's going to go through the common hepatic duct and then flow to the cystic duct to be stored in the gallbladder until we receive cholecystokinin as a signal to tell the gallbladder to contract and then from there bile is squeezed out of the gallbladder, re-enters the cystic duct.
I guess you can say this is the fifth place it would go. Re-enters the cystic duct and goes into the common bile duct. The common bile duct is the last part of the biliary tree which will then release its contents into the duodenum. And so finally our bile has reached the GI tract. The bile salts will then do their job to emulsify the fats that we've eaten. And then we'll have our bile salts get re-absorbed in the ileum before it heads back to the liver where it gets reused.
So we reuse some of the existing bile salts in the liver. And that's how our biliary tree works. Exocrine pancreas. Up Next. When the liver cells secrete bile, it is collected by a system of ducts that flow from the liver through the right and left hepatic ducts. The common hepatic duct then joins with the cystic duct from the gallbladder to form the common bile duct. This runs from the liver to the duodenum the first section of the small intestine. The gallbladder is a small, pear-shaped, muscular storage sac that holds bile and is interconnected to the liver by ducts known as the biliary tract.
See also Overview of the Liver and Gallbladder Overview of the Liver and Gallbladder Located in the upper right portion of the abdomen, the liver and gallbladder are interconnected by ducts known as the biliary tract, which drains into the first segment of the small intestine Bile is a greenish yellow, thick, sticky fluid.
It consists of bile salts, electrolytes dissolved charged particles, such as sodium and bicarbonate , bile pigments, cholesterol, and other fats lipids.
Bile has two main functions:. Bile salts aid in digestion by making cholesterol, fats, and fat-soluble vitamins easier to absorb from the intestine. Bilirubin is the main pigment in bile. Bilirubin is a waste product that is formed from hemoglobin the protein that carries oxygen in the blood and is excreted in bile.
Hemoglobin is released when old or damaged red blood cells are destroyed. Bile flows out of the liver through the left and right hepatic ducts, which come together to form the common hepatic duct.
This duct then joins with a duct connected to the gallbladder, called the cystic duct, to form the common bile duct. The common bile duct enters the small intestine at the sphincter of Oddi a ring-shaped muscle , located a few inches below the stomach.
About half the bile secreted between meals flows directly through the common bile duct into the small intestine. CCK enters the bloodstream and travels to the gallbladder where it stimulates the smooth muscle tissue in the walls of the gallbladder. When CCK reaches the gallbladder, it triggers the smooth muscle tissue in the muscularis layer of the gallbladder to contract. The contraction of smooth muscle forces bile out of the gallbladder and into the cystic duct.
From the cystic duct, bile enters the common bile duct and flows into the ampulla of Vater , where the bile ducts merge with the pancreatic duct. Bile then flows from the ampulla of Vater into the duodenum where it breaks the fats into smaller masses for easier digestion by the enzyme pancreatic lipase. Gallstones are hard masses of bile salts, pigments, and cholesterol that develop within the gallbladder. These solid masses form when the components of bile crystallize.
Growing slowly over many years as more crystallization occurs, gallstones may reach up to an inch in diameter. Most gallstones remain in the gallbladder and are harmless, but they can be pushed out of the gallbladder along with bile and potentially block the neck of the gallbladder or one of the bile ducts. Blockage of the gallbladder or cystic duct may result in cholecystitis, a painful inflammation of the gallbladder.
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