| ureteropelvic junction obstruction | <urology> A blockage of a ureter in the region where the ureter enters the anatomic pelvis (close to the bladder). This is caused most often by a kidney stone but can also be caused by external (or internal) compression from a tumour. (27 Sep 1997) |
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| action potential | <physiology> The sequential, electrochemical polarization and depolarisation that travels across the membrane of a nerve cell (neuron) in response to stimulation (touch, pain, cold, etc.) (09 Oct 1997) |
| bioelectric potential | Electrical potential's occurring in living organisms. (05 Mar 2000) |
| biological hazard potential | <radiobiology> Measure of the hazard posed by a given quantity of radioactive material in which the variation in biological effects of the various elements are accounted for. See: integrated biological hazard potential. (21 Mar 1998) |
| biotic potential | <biology, ecology> The potential growth a population of living things can expect if it were living under ideal environmental circumstances. (19 Jan 1998) |
| body surface potential mapping | Recording of regional electrophysiological information by analysis of surface potentials to give a complete picture of the effects of the currents from the heart on the body surface. It has been applied to the diagnosis of old inferior myocardial infarction, localization of the bypass pathway in wolff-parkinson-white syndrome, recognition of ventricular hypertrophy, estimation of the size of a myocardial infarct, and the effects of different interventions designed to reduce infarct size. The limiting factor at present is the complexity of the recording and analysis, which requires 100 or more electrodes, sophisticated instrumentation, and dedicated personnel. (12 Dec 1998) |
| brain potential | <physiology> The electrical charge of the brain as compared to a point on the body; the potential may be steady (DC potential) or may fluctuate at specific frequencies when recorded against time, giving rise to the electroencephalogram. (05 Mar 2000) |
| pacemaker potential | The voltage inscribed by impulses from an artificial electronic pacemaker. (05 Mar 2000) |
| generator potential | Local depolarisation of the membrane potential at the end of a sensory neurone in graded response to the strength of a stimulus applied to the associated receptor organ, e.g., a pacinian corpuscle; if the generator potential becomes large enough (because the stimulus is at least of threshold strength), it causes excitation at the nearest node of Ranvier and a propagated action potential. (05 Mar 2000) |
| receptor potential | The transmembrane potential difference of a sensory cell. Such cells are not generally excitable, but their response to stimulation is a gradual change in their resting potential. (18 Nov 1997) |
| redox potential | <chemistry> The reducing/oxidizing power of a system measured by the potential at a hydrogen electrode. (18 Nov 1997) |
| reduction potential | The inherent tendency of a compound to act as an electron donor or an electron acceptor. Measured in volts. (09 Oct 1997) |
| visual evoked potential | Voltage fluctuations that may be recorded from the occipital area of the scalp as the result of retinal stimulation by a light flashing at 1/4-second intervals; commonly summated and averaged by computer. (05 Mar 2000) |
| cell potential | <cell biology, physiology> The voltage of an electrochemical cell, the larger the cell potential, the greater the extent of reaction when equilibrium is reached. (26 Mar 1998) |
| resting potential | <physiology> The electrical potential of the inside of a cell, relative to its surroundings. Almost all animal cells are negative inside, resting potentials are in the range 20 to 100mV, 70mV typical. Resting potentials reflect the action of the sodium pump only indirectly, they are mainly caused by the subsequent diffusion of potassium out of the cell through potassium leak channels. The resting potential is thus close to the Nernst potential for potassium. See: action potential. (10 Mar 1998) |