| PRF | partial reinforcement; patient report form; perforin; plasma recognition factor; pontine reticular f... |
|---|---|
| PTRA | percutaneous transluminal renal angioplasty |
| RA | radioactive; ragocyte; ragweed antigen; rapidly adapting [receptors]; reactive arthritis; reciprocal... |
| RALPH | renal-anal-lung-polydactylyhamartoblastoma [syndrome] |
| RAP | recurrent abdominal pain; regression-associated protein; renal artery pressure; resident assessment ... |
| isolated system | <chemistry> A system which can exchange neither mass nor energy with its surroundings. (09 Jan 1998) |
|---|---|
| occlusal system | The form or design and arrangement of the occlusal and incisal units of a dentition or the teeth on a denture. Synonym: occlusal scheme. (05 Mar 2000) |
| oculomotor system | That part of the central nervous system having to do with eye movements; it is composed of pathways connecting various regions of the cerebrum, brainstem, and ocular nuclei, utilizing multisynaptic articulations. (05 Mar 2000) |
| open system | A system that exchanges energy and materials with the outside environment. (09 Oct 1997) |
| O-R system | <abbreviation> Oxidation-reduction system. (05 Mar 2000) |
| osseous part of skeletal system | The part of the skeleton composed of bone. Synonym: pars ossea systematis skeletalis. (05 Mar 2000) |
| oxidation-reduction system | <enzyme> An enzyme system in the tissues by which oxidation and reduction proceed simultaneously through the transference of hydrogen or of one or more electrons from one metabolite to another. See: oxidation-reduction. Synonym: redox system. (05 Mar 2000) |
| thoracolumbar system | See: autonomic nervous system, sympathetic part. (05 Mar 2000) |
| ecological system | <ecology> An ecosystem is the dynamic and interrelating complex of plant and animal communities and their associated non-living environment. The physical and climactic features and all the living and dead organisms in an area that are interrelated in the transfer of energy and material. An interacting complex of a community and its environment functioning as an ecological unit in nature. Differs from system in being a more rigorous definition that encompasses and requires assumptions of energetics, ecological interactions, species adaptations and so forth. (13 Nov 1997) |
| electron optical system | <apparatus> A combination of parts capable of producing and controlling a beam of electrons to produce an image of an object. (05 Aug 1998) |
| electron transport system | The mitochondrial electron transport chain. (18 Nov 1997) |
| endocrine system | The system of glands that release their secretions (hormones) directly into the circulatory system. In addition to the endocrine glands, included are the chromaffin system and the neurosecretory systems. (12 Dec 1998) |
| endomembrane system | <cell biology> Membrane system that ramifies through the cytoplasm. The membranes of the endoplasmic reticulum are separated by 50-200 nm and the cisternal space thus enclosed constitutes a separate compartment. The Golgi region is composed of flattened sacs of membrane that together with endoplasmic reticulum and lysosomes constitute the GERL system. See: smooth endoplasmic reticulum, rough endoplasmic reticulum. (18 Nov 1997) |
| endoscopy, digestive system | Visual examination of the digestive tract by means of a fibreoptic endoscope. It is used to localise, identify, and photograph pathologic alterations, to obtain biopsy material and perform other surgical interventions, and for delivery of medication. (12 Dec 1998) |
| enteric nervous system | Two ganglionated neural plexuses in the gut wall which form one of the three major divisions of the autonomic nervous system. The enteric nervous system innervates the gastrointestinal tract, the pancreas, and the gallbladder. It contains sensory neurons, interneurons, and motor neurons. Thus the circuitry can autonomously sense the tension and the chemical environment in the gut and regulate blood vessel tone, motility, secretions, and fluid transport. The system is itself governed by the central nervous system and receives both parasympathetic and sympathetic innervation. (12 Dec 1998) |