| MNA | maximum noise area |
|---|---|
| MPA | mean pulmonary arterial [pressure]; medial preoptic area; Medical Procurement Agency; medroxyprogest... |
| MPOA | medial preoptic area |
| MSA | major serologic antigen; male-specific antigen; mannitol salt agar; Medical Services Administration;... |
| MTAC | mass transfer area coefficient |
| primary centre of ossification | This is the first site where bone begins to form in the shaft of a long bone or in the body of an irregular bone. Synonym: punctum ossificationis primarium, primary point of ossification. (05 Mar 2000) |
|---|---|
| primary choana | Primitive choana, initial opening of the nasal pits and olfactory sac of the embryo into the rostral part of the primordial oronasal cavity, before the formation of the secondary palate. (05 Mar 2000) |
| primary coccidioidomycosis | A disease common in the San Joaquin Valley of California and certain additional areas in the southwestern U.S. As well as the Chaco region of Argentina, caused by inhalation of the arthroconidia of Coccidioides immitis; acute onset of symptoms resemble pneumonia or pulmonary tuberculosis, productive of sputum usually containing spores of the fungus, and accompanied by aches, malaise, severe headache, and occasionally an early erythematous or papular eruption; erythema multiforme or erythema nodosum may appear; the coccidioidin test is positive. Synonym: desert fever, San Joaquin fever, San Joaquin Valley disease, San Joaquin Valley fever, valley fever. (05 Mar 2000) |
| primary colour | The three colour's of the retinal cone pigments (red, green, blue) that may be combined to match any hue. Synonym: simple colour. (05 Mar 2000) |
| primary complex | The typical lesions of primary pulmonary tuberculosis, consisting of a small peripheral focus of infection, with hilar or paratracheal lymph node involvement. (05 Mar 2000) |
| primary constriction | The narrowing between the two arms of the chromosome represented by the centromere. (05 Mar 2000) |
| primary dental lamina | dental ledge |
| primary dentin | Dentin which forms until the root is completed. (05 Mar 2000) |
| primary dentition | The set of 20 first (deciduous) teeth. The primary dentition is as opposed to the secondary (permanent) dentition. at birth, both sets of dentition are evident by X-ray. (12 Dec 1998) |
| primary deviation | The ocular deviation seen in paralysis of an ocular muscle when the nonparalysed eye is used for fixation. (05 Mar 2000) |
| primary digestion | Digestion in the alimentary tract. (05 Mar 2000) |
| primary disease | A disease that arises spontaneously and is not associated with or caused by a previous disease, injury, or event, but which may lead to a secondary disease. (05 Mar 2000) |
| primary dried yeast | A source of dried yeast; obtained from suitable strains of Saccharomyces cerevisiae grown in media other than those required for the production of beer. (05 Mar 2000) |
| primary drives | Those drives such as hunger and thirst which stem from the biological needs of an organism. Synonym: primary drives. (05 Mar 2000) |
| primary dysmenorrhoea | <gynaecology> Painful menses due to a functional disturbance and not due to organic factors such as growths, inflammation or anatomy. (06 Mar 1998) |