| primary producer | An organism that uses light to synthesise new organic material from carbon dioxide. (09 Oct 1997) |
|---|---|
| primary production | Production of organic substances by photosynthesis, the quantity of material so produced per unit time. (09 Oct 1997) |
| primary progressive cerebellar degeneration | A familial ataxic condition related to cerebellar degeneration. (05 Mar 2000) |
| primary pulmonary hypertension | A condition where there is increased blood pressure in the pulmonary arteries with otherwise normal heart and lungs. The cause is unknown, but there is diffuse narrowing of the pulmonary arteries resulting in increased arteriolar pressures. Secondary heart failure ensues without correction of this problem. There is an increased incidence of this disease in females between the ages of 20 and 40 years. Treatment may include a heart and lung transplant in select cases. (27 Sep 1997) |
| primary pulmonary lobule | The part of the airway consisting of a respiratory bronchiole and all of its branches. Synonym: primary pulmonary lobule, respiratory lobule. (05 Mar 2000) |
| primary pyoderma | A pyoderma, such as impetigo, in which pus formation is an essential part of the disease. (05 Mar 2000) |
| primary radiation | An incident X-ray beam. (05 Mar 2000) |
| primary rays | Cosmic ray's in the form in which they first strike the atmosphere, X-ray's generated at the focal spot of the tube. Synonym: direct rays. (05 Mar 2000) |
| primary reaction | <dermatology> The cutaneous and sometimes systemic reactions associated with vaccination with smallpox vaccine. (18 Nov 1997) |
| primary refractory anaemia | Any of a group of anaemic conditions in which there is persistent, frequently advanced anaemia that is not successfully treated by any means except blood transfusions, and that is not associated with another primary disease. (05 Mar 2000) |
| primary reinforcement | Satisfaction of physiological needs or drives, such as that supplied by food or sleep. (05 Mar 2000) |
| primary rejection | A rejection occurring more than seven days after transplantation, mainly from a cellular immune response. (05 Mar 2000) |
| primary renal calculus | A calculus formed in an apparently healthy urinary tract, usually composed of oxalates, urates, or cystine. (05 Mar 2000) |
| primary renal tubular acidosis | A metabolic defect in the mechanism of urinary acidification that may be either the transient type, with onset in infancy, or the persistent type, with onset in childhood or adult years; both types are familial. (05 Mar 2000) |
| primary reninism | Overproduction of renin by juxtaglomerular cells in the absence of a stimulus (such as decreased renal perfusion); leads to hyperaldosteronism, hypertension, hypokalaemia, and oedema. (05 Mar 2000) |