Context: In vertebrates the gallbladder (also gall bladder, biliary vesicle or cholecyst) is a small organ where bile (a fluid produced by the liver) is stored and concentrated before it is released into the small intestine. Humans can live without a gallbladder. The surgical removal of the gallbladder is called a cholecystectomy., Bilirubin (formerly referred to as haematoidin and discovered by Rudolf Virchow in 1847) is a yellow compound that occurs in the normal catabolic pathway that breaks down heme in vertebrates. This catabolism is a necessary process in the body's clearance of waste products that arise from the destruction of aged red blood cells. First the hemoglobin gets stripped of the heme molecule which thereafter passes through various processes of porphyrin catabolism, depending on the part of the body in which the breakdown occurs. For example, the molecules excreted in the urine differ from those in the feces. The production of biliverdin from heme is the first major step in the catabolic pathway, after which the enzyme biliverdin reductase performs the second step, producing bilirubin from biliverdin. , A bile duct is any of a number of long tube - like structures that carry bile . Bile , required for the digestion of food , is secreted by the liver into passages that carry bile toward the hepatic duct , which joins with the cystic duct ( carrying bile to and from the gallbladder ) to form the common bile duct , which opens into the intestine . The biliary tree ( see below ) is the whole network of various sized ducts branching through the liver . The path is as follows : Bile canaliculi  Canals of Hering  interlobular bile ducts  intrahepatic bile ducts  left and right hepatic ducts merge to form  common hepatic duct exits liver and joins  cystic duct ( from gall bladder ) forming  common bile duct  joins with pancreatic duct  forming ampulla of Vater  enters duodenum, Vertebrates comprise all species of animals within the subphylum Vertebrata (chordates with backbones). Vertebrates represent the overwhelming majority of the phylum Chordata, with currently about 64,000 species described. Vertebrates include the jawless fish and the jawed vertebrates, which include the cartilaginous fish (sharks and rays) and the bony fish. , Lecithin (from the Greek "lekithos", "egg yolk") is a generic term to designate any group of yellow-brownish fatty substances occurring in animal and plant tissues, which are amphiphilic - they attract both water and fatty substances (and so are both hydrophilic and lipophilic), and are used for smoothing food textures, dissolving powders (emulsifying), homogenizing liquid mixtures, and repelling sticking materials.
Lecithins are usually phospholipids, composed of phosphoric acid with choline, glycerol or other fatty acids usually glycolipids or triglyceride. Glycerophospholipids in lecithin include phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidic acid., The liver is a vital organ of vertebrates and some other animals. In the human, it is located in the upper right quadrant of the abdomen, below the diaphragm. The liver has a wide range of functions, including detoxification of various metabolites, protein synthesis, and the production of biochemicals necessary for digestion., Bile or gall is a dark green to yellowish brown fluid, produced by the liver of most vertebrates, that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bile), and stored and concentrated in the gallbladder (gallbladder bile). After eating, this stored bile is discharged into the duodenum. The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts., The duodenum
is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine may be used instead of duodenum. In mammals the duodenum may be the principal site for iron absorption., In biology, lipids comprise a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, and acting as structural components of cell membranes. Lipids have applications in the cosmetic and food industries as well as in nanotechnology., Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. In chemical digestion, enzymes break down food into the small molecules the body can use., The small intestine or small bowel is the part of the gastrointestinal tract between the stomach and the large intestine, and is where most of the end absorption of food takes place. The small intestine has three distinct regions  the duodenum, jejunum, and ileum. The duodenum receives bile and pancreatic juice through the pancreatic duct, controlled by the sphincter of Oddi. The primary function of the small intestine is the absorption of nutrients and minerals from food., Cholesterol, from the Ancient Greek "chole-" (bile) and "stereos" (solid) followed by the chemical suffix "-ol" for an alcohol, is an organic molecule. It is a sterol (or modified steroid), a type of lipid molecule, and is biosynthesized by all animal cells, because it is an essential structural component of all animal cell membranes; essential to maintain both membrane structural integrity and fluidity. Cholesterol enables animal cells to dispense with a cell wall (to protect membrane integrity and cell viability), thereby allowing animal cells to change shape and animals to move (unlike bacteria and plant cells, which are restricted by their cell walls)., Subject: bile duct, Relation: subclass_of, Options: (A) alcohol (B) ancient greek (C) animal (D) biology (E) brown (F) change (G) digestion (H) eating (I) energy (J) enzyme (K) fat (L) feces (M) fish (N) fluid (O) food (P) function (Q) greek (R) green (S) iron (T) liquid (U) majority (V) nanotechnology (W) organ (X) part (Y) plant (Z) process ([) production (\) red (]) second (^) section (_) species (`) steroid (a) sterol (b) stream (c) suffix (d) vertebrata (e) water (f) yellow
Output: organ