Author: Glossary
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Islets of langerhans
The endocrine parts of the pancreas; glucagon is secreted by the α-cells and insulin by the β-cells. Cells in the pancreas that produce insulin in response to the presence of glucose (sugar) in the bloodstream. The failure of insulin production results in the disease called diabetes. Groups of cells in the pancreas which secrete the…
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Ischaemic heart disease or coronary heart disease
Group of syndromes arising from failure of the coronary arteries to supply sufficient blood to heart muscles; associated with atherosclerosis of coronary arteries. A disease of the heart caused by a failure in the blood supply, as in coronary thrombosis.
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Ischaemia
Inadequate blood supply to a tissue. A deficient blood supply to a part of the body. Bloodlessness of a part of the body, due to contraction, spasm, constriction or blocking (by embolus or by thrombus) of the arteries: for example, of the heart. Inadequate blood flow to a particular organ or tissue, often resulting from…
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Irritable bowel syndrome (IBS)
Also known as spastic colon or mucous colitis. Abnormally increased motility of the large and small intestines, leading to pain and alternating diarrhoea and constipation; often precipitated by emotional stress. This is a common and benign condition of the colon, taking different forms but usually characterized by alternating constipation and diarrhea. There is often some…
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Ionising radiation
Electromagnetic radiation that ionises the air or water through which it passes, e.g. X-rays and y-rays. Used for the sterilisation of food, etc., by irradiation.
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Ionisation
The process whereby the positive and negative ions of a salt or other compound separate when dissolved in water. The degree of ionisation of an acid or alkali determines its strength.
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Ion-exchange resin
An organic compound that will adsorb ions under some conditions and release them under others. Synthetic organic substances of high molecular weight. They replace certain negative or positive ions that they encounter in solutions. An ionizable synthetic substance, which may be acid or basic, used accordingly to remove either acid or basic ions from solutions.…
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Ion
An atom or molecule that has lost or gained one or more electrons, and thus has an electric charge. Positively charged ions are cations, because they migrate towards the cathode (negative pole) in solution, while negatively charged ions (anions) migrate towards the positive pole (anode). An atom or molecule possessing a positive or a negative…
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Iodised salt
Usually 1 part of iodate in 25000-50000 parts of salt, as a means of ensuring adequate iodine intake in regions where deficiency is a problem.
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Iodine number (iodine value)
Carbon-carbon double bonds in unsaturated compounds can react with iodine; this provides a means of determining the degree of unsaturation of a fat or other compound by the uptake of iodine.