| essential amino acid | <biochemistry> Those amino acids that cannot be synthesised by an organism and must therefore be present in the diet. The term is often applied anthropocentrically to those amino acids required by humans (Ileu, Leu, Lys, Met, Phe, Thr, Try, & Val), though rats need two more (Arg & His). (18 Nov 1997) |
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| essential amino acids | Alpha-amino acids nutritionally required by an organism and which must be supplied in its diet (i.e., cannot be synthesised by the organism) either as free amino acid or in proteins. (05 Mar 2000) |
| essential anaemia | An obsolete term for pernicious anaemia; also used formerly for any type of anaemia of unknown mechanism. (05 Mar 2000) |
| essential anisocoria | A common (20% of normals) benign inequality of the pupils that may change from one hour to the next. Synonym: essential anisocoria, physiologic anisocoria, simple-central anisocoria. (05 Mar 2000) |
| essential bradycardia | A slow pulse for which no cause can be discovered. Synonym: idiopathic bradycardia. (05 Mar 2000) |
| essential dysmenorrhoea | <gynaecology> Painful menses due to a functional disturbance and not due to organic factors such as growths, inflammation or anatomy. (27 Sep 1997) |
| essential fatty acid | <biochemistry> The three fatty acids required for growth in mammals, arachidonic, linolenic and linoleic acids. Only linoleic acid needs to be supplied in the diet, the other two can be made from it. (18 Nov 1997) |
| essential fever | Fever without known infectious disease. (05 Mar 2000) |
| essential food factors | Those substances required in the diet: certain amino acids and unsaturated fatty acids, vitamins, essential minerals, etc. (05 Mar 2000) |
| essential gene | <genetics> Any gene that, if it does not workcorrectly, kills the organism. (09 Oct 1997) |
| essential hypertension | Hypertension without known cause. Synonym: idiopathic hypertension, primary hypertension. (05 Mar 2000) |
| essential oils | Plant products, usually somewhat volatile, giving the odours and tastes characteristic of the particular plant, thus possessing the essence, e.g., citral, pinene, camphor, menthane, terpenes; usually, the steam distillates of plants or oils of plants obtained by pressing out the rinds of a particular plant. See: volatile oil. (05 Mar 2000) |
| essential phthisis bulbi | A softening of the eyeball (ophthalmomalacia) and reduction in size, not due to inflammation. (05 Mar 2000) |
| essential progressive atrophy of iris | Progressive atrophy of the iris without inflammatory signs, characterised by patchy loss of all layers of the iris with hole formation, migration of the pupil, degeneration of the corneal endothelium, peripheral anterior synechiae, and secondary glaucoma; usually unilateral, predominantly affecting women in their middle years. (05 Mar 2000) |
| essential pruritus | Itching that occurs independently of skin lesions. (05 Mar 2000) |