Dr. Curry
Our bodies do some pretty amazing things, and it's all inter-related. So the story starts with worn-out red blood cells. The spleen filters these out and breaks them down and turns them into bile salts and other things. So we have bile salts floating around in our bodies. The liver filters these bile salts out of our system, collects them and sends them to the gallbladder. The gallbladder is a small organ that lives under the liver. It is a hollow organ designed to hold liquid. A bladder. Bile used to be called gall. And that's why it's called a gall bladder.
The liver sends the bile salts to the gallbladder where they are stored. The liver also sends waste products down too. More on that later. The gallbladder collects the liquid, extracts water, and concentrates it. The end result is bile, a green, strongly alkaline, bitter, corrosive liquid.
When fat globules arrive in the upper reaches of the small intestine, the duodenum, it triggers a hormone. The hormone tells the gallbladder that bile is needed, so the gallbladder does a muscular contraction and dumps a large quantity of bile into the duodenum to deal with the fat. The enzymes that digest fat can only work on the surface of the fat globules. To effectively digest the fat, the surface area needs to be as large as possible so the enzymes can get at the fat. The bile acts as a detergent on the fat and causes the large fat globules to break down into microscopic droplets thereby creating a much greater surface for the enzymes to work on to digest the fat.