| secondary metabolite | <biochemistry> Chemicals that are usually unique to one organism or class of organisms, and are not essential to cell survival. They perform specialised functions, for example, degrading food sources or fighting off other organisms. Many of the chemicals that plants or microorganisms produce that are of biochemical interest are secondary metabolites, including antibiotics. (14 Nov 1997) |
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| secondary methemoglobinaemia | Methemoglobinaemia caused by various chemical agents, such as nitrites. Synonym: enterogenous methemoglobinaemia, secondary methemoglobinaemia. (05 Mar 2000) |
| secondary myeloid metaplasia | Myeloid metaplasia occurring in individuals with another disease. Synonym: symptomatic myeloid metaplasia. (05 Mar 2000) |
| secondary narcissism | In psychoanalysis, the psychic energy once attached to external objects, but now withdrawn from those objects and reinvested in the ego. (05 Mar 2000) |
| secondary nodule | A lymphatic nodule having a germinal centre. (05 Mar 2000) |
| secondary nondisjunction | Nondisjunction occurring in an aneuploid cell that was the result of a primary nondisjunction. (05 Mar 2000) |
| secondary oocyte | <gynaecology> An oocyte which arises from the primary oocyte (which was diploid) after it completes the first meiotic division after the body has become sexually mature. The secondary oocyte eventually divides into the mature egg or ovum (which is haploid) and a polar body (which degenerates), thus ending the second meiotic division. (13 Nov 1997) |
| secondary palate | The posterior portion of the embryonic palate, which forms from the palatal processes of the embryonic maxilla and develops into the hard palate. (05 Mar 2000) |
| secondary pellagra | Pellagra resulting from any morbid condition that impairs nutrition by increasing the requirement or reducing the available supply of vitamins. (05 Mar 2000) |
| secondary point of ossification | This is the centre of bone formation appearing later than the punctum ossificationis primarium, usually in epiphysis. Synonym: punctum ossificationis secundarium, secondary point of ossification. (05 Mar 2000) |
| secondary process | In psychoanalysis, the mental process directly related to the learned and acquired functions of the ego and characteristic of conscious and preconscious mental activities; marked by logical thinking and by the tendency to delay gratification by regulation of the discharge of instinctual demands. Compare: primary process. (05 Mar 2000) |
| secondary product | <plant biology> End product of plant cell metabolism, which accumulates in or is secreted from, the cell. Includes anthocyanins, alkaloids, etc. Some are of major economic importance, for example as drugs. In contrast to a primary product that is involved in the vital metabolism of the plant. (18 Nov 1997) |
| secondary pulmonary lobule | A pyramidal mass of lung tissue whose sides are bounded by the incomplete interlobular connective tissue septa and whose base, which is 1 to 2 cm in diameter, usually faces the pleural surface of the lung; lobule's that occupy a more central position in the lung are not well defined and are considered to consist of three to five pulmonary acini with proximate terminal bronchioles. (05 Mar 2000) |
| secondary pyoderma | A pyoderma in which an existing skin lesion (eczema, herpes, seborrheic dermatitis, etc.) becomes secondarily infected. (05 Mar 2000) |
| secondary radiation | Secondary radiation emitted from the interaction of X-rays with matter; generally lower in energy, with a directional distribution which depends on the energy of the incident radiation. Synonym: secondary radiation. (05 Mar 2000) |