| ion selective electrode | An electrode half cell, with a semi permeable membrane that is permeable only to a single ion. The electrical potential measured between this and a reference half cell (e.g. A calomel electrode) is thus the Nernst potential for the ion. Given that the solution filling the ion selective electrode is known, the activity (rather than concentration) of the ion in the unknown solution can be measured. Commercial ion selective electrodes frequently use a hydrophobic membrane containing an ionophore, such as valinomycin (for potassium) or monensin (for sodium). A pH electrode is made with a thin membrane of pH sensitive (i.e. Proton permeable) glass. (18 Nov 1997) |
|---|---|
| oxidation-reduction electrode | An electrode capable of measuring oxidation-reduction potential. See: quinhydrone electrode. Synonym: redox electrode. (05 Mar 2000) |
| oxygen electrode | A sensitive method to detect oxygen consumption, involves a PTFE (Teflon) membrane. (18 Nov 1997) |
| therapeutic electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| electrode | <chemistry> Any terminal that conducts an electric current into or away from various conducting substances in a circuit (such as the anode or cathode of a battery). (09 Jan 1998) |
| electrode catheter ablation | A method of ablating the site of origin of arrhythmias whereby high energy electric shocks are delivered by intravascular catheters. (05 Mar 2000) |
| electrode knife | A blade-shaped electrical instrument used to cut tissues by means of a high-frequency electrical current. (05 Mar 2000) |
| enzyme electrode | A type of biosensor. An enzyme is immobilised on the surface of an electrode, and when the enzyme catalyses its reaction, electrons are transferred from the reactant to the electrode, and a current is generated, which can then be measured. (14 Nov 1997) |
| exciting electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| exploring electrode | An electrode placed on or near an excitable tissue; in unipolar electrocardiography, the electrode is placed on the chest in the region of the heart and paired with an indifferent electrode. (05 Mar 2000) |
| localizing electrode | A small electrode whose exciting effect is used to stimulate or record potentials from a localised area. Synonym: exciting electrode, localizing electrode, therapeutic electrode. (05 Mar 2000) |
| absolute terminal innervation ratio | The number of motor endplates divided by the number of terminal axons related to them. (05 Mar 2000) |
| amino-terminal | <biochemistry> The end of a protein or polypeptide chain with the unattached amino group or the aminoacyl residue containing it. Each amino acid in the chain has an amino group on one side, which is attached to the carboxyl group (COOH group) of the previous amino acid, and a carboxyl group on the other side (which is attached to the amino group of the next amino acid). The other end of the polypeptide chain is called the carboxyl terminal. Synonym: NH2-terminal. (14 Aug 2000) |
| amino-terminal residue | <biochemistry> The only amino acid residue in a polypeptide chain that has a free alpha-amino group, it defines the amino terminus of the polypeptide. (09 Oct 1997) |
| axonal terminal boutons | The somewhat enlarged, often club-shaped endings by which axons make synaptic contacts with other nerve cells or with effector cells (muscle or gland cells). As isolated, by homogenizing brain or spinal cord, they contain acetylcholine and the related enzymes. Terminals contain neurotransmitters of various kinds, sometimes more than one. These can be demonstrated by chemical analysis and immunocytochemical methods. See: synapse. Synonym: axonal terminal boutons, end-feet, neuropodia, pieds terminaux, synaptic boutons, synaptic endings, synaptic terminals, terminal boutons, bouton terminaux. (05 Mar 2000) |