Bile Acids: From 1 Different Sources
the organic acids in bile; mostly occurring as bile salts (sodium glycocholate and sodium taurocholate). They are cholic acid, deoxycholic acid, glycocholic acid, and taurocholic acid.
cebile-acid sequestrant a drug that binds to bile acids, forming a complex that is excreted in the faeces. Bile acids are formed in the liver from *cholesterol and the effect of loss of bile acids is a reduction in total body cholesterol and a decrease in *low-density lipoprotein serum levels. These drugs, which include *colestyramine and *colestipol, are used to treat patients with abnormally high blood cholesterol levels who are liable to develop coronary heart disease.
Chemical compounds that are the basic building-blocks of all proteins. Each molecule consists of nitrogenous amino and acidic carboxyl groups of atoms joined to a group of carbon atoms. Polypeptides are formed by amino-acid molecules linking via peptide bonds. Many polypeptides link up in various con?gurations to form protein molecules. In humans, proteins are made up from 20 di?erent amino acids: nine of these are labelled ‘essential’ (or, as is now preferred, ‘indispensable’) amino acids because the body cannot manufacture them and is dependent on the diet for their provision. (See also INDISPENSABLE AMINO ACIDS.)... amino acids
A thick, bitter, greenish-brown ?uid, secreted by the liver and stored in the gall-bladder (see LIVER). Consisting of water, mucus, bile pigments including BILIRUBIN, and various salts, it is discharged through the bile ducts into the intestine a few centimetres below the stomach. This discharge is increased shortly after eating, and again a few hours later. It helps in the digestion and absorption of food, particularly fats, and is itself reabsorbed, passing back through the blood of the liver. In JAUNDICE, obstruction of the bile ducts prevents discharge, leading to a build-up of bile in the blood and deposition in the tissues. The skin becomes greenish-yellow, while the stools become grey or white and the urine dark. Vomiting of bile is a sign of intestinal obstruction, but may occur in any case of persistent retching or vomiting, and should be fully investigated.... bile
The channel running from the gall-bladder (see LIVER) to the DUODENUM; carries BILE.... bile duct
Three acids – arachidonic, linolenic and tinoleic – which are essential for life, but which the body cannot produce. They are found in natural vegetable and ?sh oils and their functions are varied. EFAs have a vital function in fat metabolism and transfer and they are also precursors of PROSTAGLANDINS.... essential fatty acids
See INDISPENSABLE AMINO ACIDS.... essential amino acids
This is the new, preferred term for essential amino acids – amino acids which are essential for the body’s normal growth and development, but which the body is unable to produce. Nine essential amino acids exist – HISTIDINE, ISOLEUCINE, LEUCINE, LYSINE, METHIONINE, PHENYLALANINE, THREONINE, TRYPTOPHAN, and VALINE – and they are present in foods rich in protein: dairy products, eggs, meat, and liver.... indispensable amino acids
coloured compounds – breakdown products of the blood pigment *haemoglobin – that are excreted in *bile. The two most important bile pigments are bilirubin, which is orange or yellow, and its oxidized form biliverdin, which is green. Mixed with the intestinal contents, they give the brown colour to the faeces (see urobilinogen).... bile pigments
sodium glycocholate and sodium taurocholate – the alkaline salts of *bile – necessary for the emulsification of fats. After they have been absorbed from the intestine they are transported to the liver for reuse.... bile salts
Substances found in all living matter that have a fundamental role in the propagation of life. Nucleic acids provide the inherited coded instructions (or “blueprint”) for an organism’s development.
There are 2 types of nucleic acid: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). In all plant and animal cells, including human cells, DNA permanently holds the coded instructions, which are translated and implemented by RNA. DNA is the main constituent of chromosomes, which are carried in the nucleus (central unit) of the cell.
DNA and RNA are similar in structure, both comprising long, chain-like molecules. However, DNA usually consists of 2 intertwined chains, whereas RNA is generally single-stranded.
The basic structure of DNA has been likened to a rope ladder, the chains forming the 2 sides, with interlinking structures in between forming the rungs.
The ladder is twisted into a spiral shape called a double helix.
Each DNA chain has a “backbone” consisting of a string of sugar and phosphate chemical groups. Attached to each sugar is a chemical called a base, which can be any of 4 types (adenine, thymine, guanine, and cytosine) and forms half a rung of the DNA ladder. The 4 bases can occur in any sequence along the chain. The sequence, which may be many millions of individual bases long, provides the code for the activities of the cell (see genetic code).
RNA is like a single strand of DNA; the main difference is that the base thymine is replaced by another base, uracil.When a cell undergoes mitotic (see mitosis) division, identical copies of its DNA must go to each of the 2 daughter cells. The 2 DNA chains separate, and 2 more chains are formed, side by side with the original chains. Because only certain base pairings are possible, the new double chains are identical to the original DNA molecule. Each of a person’s cells carries the same DNA replica that was present in the fertilized ovum, so the DNA message passes from one generation of cells to the next.... nucleic acids
(n-3 fatty acids) polyunsaturated fatty acids with a double bond at the third carbon atom in the chain. Omega-3 fatty acids are essential for brain development and are also associated with many health benefits, including protection against heart disease and possibly stroke and inflammatory conditions. There are three major types: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). The main source of EPA and DHA is fish oils. Vegetarians rely on EPA and DHA being synthesized by the body from dietary sources of ALA. See also essential fatty acids.... omega-3 fatty acids
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