| accelerator | 1. Anything that increases rapidity of action or function. 2. In physiology, a nerve, muscle, or substance that quickens movement or response. 3. A catalytic agent used to hasten a chemical reaction. 4. In nuclear physics, a device that accelerates charged particles (e.g., protons) to high speed in order to produce nuclear reactions in a target, often for the production of radionuclides or for radiation therapy. Synonym: accelerant. Origin: L. Accelerans, pres. P. Of ac-celero, to hasten, fr. Celer, swift (05 Mar 2000) |
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| accelerator factor | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| accelerator fibres | Postganglionic sympathetic nerve fibre's originating in the superior, middle, and inferior cervical ganglia of the sympathetic trunk, conveying nervous impulses to the heart that increase the rapidity and force of the cardiac pulsations. Synonym: augmentor fibres. (05 Mar 2000) |
| accelerator globulin | Globulin in serum that promotes the conversion of prothrombin to thrombin in the presence of thromboplastin and ionised calcium. See: factor Va, factor V, serum accelerator globulin. (05 Mar 2000) |
| accelerator nerves | Certain of the cardiopulmonary splanchnic nerves establishing the sympathetic innervation of the heart; originating from ganglion cells of the superior, middle, and inferior cervical ganglion of the sympathetic trunk, the unmyelinated efferent fibres of the accelerator nerve's stimulate an increase in the heart rate. (05 Mar 2000) |
| railgun accelerator | <radiobiology> Projectile accelerator which accelerates the particle using electromagnetic forces which arise when the particle completes an electrical circuit between two conducting rails connected to a source of high current. (09 Oct 1997) |
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| plasma accelerator globulin | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| proserum prothrombin conversion accelerator | A coagulation (clotting) factor. Classic haemophilia (haemophilia A) is due to a congenital deficiency in the amount (or activity) of factor VIII. Factor VIII is also known as antihemophiliac factor (AHF) or antihemophiliac globulin (AHG). The gene for factor VIII (that for classic haemophilia) is on the X chromosome so females can be silent carriers without symptoms and males can be haemophiliacs. (12 Dec 1998) |
| prothrombin accelerator | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| serum accelerator | <chemical> Heat- and storage-stable plasma protein that is activated by tissue thromboplastin to form factor viia in the extrinsic pathway of blood coagulation. The activated form then catalyses the activation of factor x to factor xa. Chemical name: Blood-coagulation factor VII (12 Dec 1998) |
| serum accelerator globulin | A substance in serum that accelerates the conversion of prothrombin to thrombin in the presence of thromboplastin and calcium; produced by the action of traces of thrombin upon plasma accelerator globulin. (05 Mar 2000) |
| serum prothrombin conversion accelerator | <chemical> Heat- and storage-stable plasma protein that is activated by tissue thromboplastin to form factor viia in the extrinsic pathway of blood coagulation. The activated form then catalyses the activation of factor x to factor xa. Chemical name: Blood-coagulation factor VII (12 Dec 1998) |
| linear accelerator | <apparatus> A sophisticated external beam radiotherapy machine which has the capabilities of focussing irradiation (although not very finely). Acronym: LinAC (16 Dec 1997) |