| PMF | platelet membrane fluidity; progressive massive fibrosis; proton motive force; pterygomaxillary foss... |
|---|---|
| pmf | proton motive force |
| PMR | patient meta-record; perinatal mortality rate; periodic medical review; physical medicine and rehabi... |
| PRE | photoreacting enzyme; physician's report of examination; pigmented retinal epithelium; preplacement ... |
| PRR | proton relaxation rate; pulse repetition rate |
| 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) |
| membrane potential | <physiology> More correctly, transmembrane potential difference: the electrical potential difference across a plasma membrane. See: resting potential, action potential. (18 Nov 1997) |
| chemical potential | <chemistry> The work required (in j mol 1) to bring a molecule from a standard state (usually infinitely separated in a vacuum) to a specified concentration. More usually employed as chemical potential difference, the work required to bring one mole of a substance from a solution at one concentration to another at a different concentration, __ = RT.In (c2/cl). This definition is useful in studies of active transport, note that, for charged molecules, the electrical potential difference must also be considered (see electrochemical potential). (18 Nov 1997) |
| miniature end plate potential | <physiology> Small fluctuations (typically 0.5 mV) in the resting potential of postsynaptic cells. They are the same shape as, but much smaller than, the end plate potentials caused by stimulation of the presynaptic cell. Miniature end plate potentials are considered as evidence for the quantal release of neurotransmitters at chemical synapses, a single miniature end plate potential resulting from the release of the contents of a single synaptic vesicle. (12 Jan 1998) |
| water potential | <plant biology> The chemical potential (i.e. Free energy per mole) of water in plants. Water moves within plants from regions of high water potential to regions of lower water potential, i.e. Down gradient. (18 Nov 1997) |
| myogenic potential | Action potential of muscle. (05 Mar 2000) |
| postsynaptic potential | In a synapse, a change in the resting potential of a postsynaptic cell following stimulation of the presynaptic cell. For example: in a cholinergic synapse, the release of acetylcholine from the presynaptic cell causes channels to open in the postsynaptic cell. Each channel opening causes a small depolarisation, known as a miniature end plate potential (mepp), these sum to produce an excitatory postsynaptic potential. (18 Nov 1997) |
| potential | Existing and ready for action but not yet active. (18 Nov 1997) |
| potential energy | <chemistry> Energy due to position, it is stored energy which can be used to do work. (09 Jan 1998) |