Bile

Your liver makes a yellow-green fluid.

It is mostly made of water. This fluid helps you digest fats from food.

The liver makes it all the time. A small bag stores it for later. When you eat, the fluid moves to your gut. It breaks big fat drops into tiny bits. This helps your body take in vitamins. It can even kill tiny germs in your food. This fluid is very important for staying healthy.

Your liver makes a yellow-green fluid called bile.

Most of this fluid is water. It also contains bile salts. These salts help your body digest fats.

When you eat, bile moves from a storage bag called the gallbladder. It goes into the first part of your small intestine. The bile salts work like soap. They break big fat drops into tiny bits. We call these tiny bits micelles. This makes it easier for enzymes to break down the fat. Without bile, your body cannot absorb fats well. You also need bile to take in vitamins like A, D, E, and K.

Bile does other jobs too. It helps kill tiny germs in your food. It also helps stop acid from your stomach. Sometimes, bits of cholesterol can form hard lumps. These are called gallstones. If a gallstone blocks the path, it can cause problems. This might make your skin look yellow. This is called jaundice.

Bile is a very important part of staying healthy.

Bile is a yellow-green fluid that helps your body work.

Most animals called vertebrates make this fluid in their liver. It is very important for digesting lipids, which are fats. Without it, your body could not use many nutrients. Bile also helps move waste out of your system. It acts as a path for a byproduct called bilirubin. This bilirubin comes from your recycled red blood cells.

This fluid works in a very clever way.

It acts like a surfactant to help break down fats. Bile salts have two different sides. One side likes water, but the other side hates it. These salts gather around fat droplets to form tiny groups called micelles. These micelles are usually only 1 to 50 micrometers wide. This small size makes it easier for enzymes to reach the fat. Then, your body can absorb the fats and vitamins.

People have thought about bile for a very long time. In ancient times, doctors believed the body had four vital fluids. They called these fluids humors. Two of these humors were related to bile. One was called yellow bile, or choler. The other was called black bile. They thought these fluids affected how people felt. For example, they thought too much yellow bile caused aggression. These old ideas even gave us the word cholera.

There are many specific facts about how bile is made. In humans, bile is mostly made of water. About 97 to 98 percent of it is water. The rest includes bile salts and fats like cholesterol. It also contains bilirubin, which is an orange-yellow pigment. There is also biliverdin, which is a green pigment. The pH of bile can change depending on where it is. Bile in the gallbladder is more acidic than bile in the ducts.

Bile is linked to many things you might see.

For example, bile salts can work like soap. People have used ox gall to make a special soap for cleaning clothes. In some places, like the Philippines, people use bile to flavor food. It can also cause health issues if it is blocked. If a gallstone blocks the path, it can cause jaundice. This makes a person's skin look yellow. This happens because bilirubin builds up in the blood.

Bile is a yellow-green fluid produced by the liver of most vertebrates.

Its primary role is to aid in the digestion of lipids, which are fats, within the small intestine. In humans, the liver produces this fluid continuously. The gallbladder then stores and concentrates the bile until it is needed. Once a person eats, the gallbladder discharges the bile into the duodenum. The duodenum is the first section of the small intestine. This discharge happens through a specific opening called the ampulla of Vater in the duodenal wall.

The chemical makeup of human bile is very specific. It is composed of 97% to 98% water. The remaining portion includes 0.7% bile salts and 0.2% bilirubin. It also contains 0.51% fats, such as cholesterol, fatty acids, and lecithin. Additionally, it contains 200 meq/L of inorganic salts. Two main pigments give bile its color. Bilirubin is an orange-yellow pigment. Biliverdin is an oxidized form of bilirubin that appears green.

Bile works through a process called emulsification to help digest fats.

It acts as a surfactant, which is a substance that helps break up liquids. Bile salt anions are unique because they are hydrophilic on one side and hydrophobic on the other. This means one side likes water while the other side repels it. These salts aggregate around lipid droplets, such as triglycerides and phospholipids, to form structures called micelles. In humans, these micelles typically have a diameter between 1 and 50 micrometers. The hydrophobic sides face the fat, while the hydrophilic sides face outward.

This microscopic structure is essential for nutrient absorption. The negative charge on the hydrophilic sides prevents the fat droplets from re-aggregating into larger particles. This dispersion creates a much larger surface area for an enzyme called pancreatic lipase. This enzyme digests the triglycerides. The process breaks a triglyceride down into two fatty acids and one monoglyceride. These components are then absorbed by the villi on the intestinal walls. After crossing the intestinal membrane, the fatty acids reform into triglycerides. They are then absorbed into the lymphatic system through structures called lacteals. Without bile salts, most lipids would be excreted in feces undigested.

Bile also serves several other important biological functions. It is necessary for the absorption of fat-soluble vitamins, specifically vitamins A, D, E, and K. Beyond digestion, bile acts as a route for excreting bilirubin. Bilirubin is a byproduct created when the liver recycles red blood cells. This process involves converting hemoglobin through a method called glucuronidation.

Furthermore, bile is often alkaline, meaning it has a high pH. The pH of common duct bile ranges from 7.50 to 8.05. In contrast, gallbladder bile is more acidic, with a pH between 6.80 and 7.65. This alkalinity helps neutralize excess stomach acid as it enters the duodenum. Bile salts also act as bactericides, which helps destroy many microbes found in food.

Medical issues can arise if the bile system is disrupted. If bile is absent, fats cannot be digested and are excreted in feces. This condition is called steatorrhea. In this state, feces may appear white or gray and greasy instead of brown. This can lead to deficiencies in essential fatty acids and vitamins. Another issue is the formation of gallstones, which occur when cholesterol in the bile accretes into lumps. If a gallstone blocks the bile ducts, it causes biliary obstruction. This can lead to jaundice, where bilirubin builds up in the bloodstream. Obstructions can also cause cholecystitis or gallstone pancreatitis.

Historically, humans have held many different views regarding bile. In Western medical theories from antiquity through the Middle Ages, doctors believed health depended on four "humors." These were vital fluids: blood, phlegm, yellow bile, and black bile. They believed yellow bile, or choler, influenced aggression. They thought excess black bile caused depression. These theories even influenced modern language. The Greek word for bile, "kholē," is the root of the English word cholera. Similarly, the term "melancholia" relates to these ancient ideas about bodily fluids.