| FAC | familial adenomatosis coli; femoral arterial cannulation; ferric ammonium citrate; 5-fluorouracil, A... |
|---|---|
| FAR | Federal acquisitions regulation; fractional albumin rate; fresh bone marrow |
| FCR | flexor carpi radialis; fractional catabolic rate |
| FDR | fractional disappearance rate |
| FECO2 | fractional concentration of carbon dioxide in expired gas |
| electrical axis | The net direction of the electromotive forces developed in the heart during its activation, usually represented in the frontal plane. See: triaxial reference system. (05 Mar 2000) |
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| electrical conductivity | <radiobiology> Degree to which a substance conducts electric current. Can be defined by: (current density) = (conductivity) (applied electric field) Electrons and ions both contribute to current in proportion to their mobility in the system. In a plasma with a magnetic field, there is no longer a one-to-one correspondence between current and electric field. Instead, the current in each direction can be due to combinations of the electric fields in all the other directions. In this case, the current density and the electric field are vectors, and the conductivity becomes a tensor (matrix) which relates them. (09 Oct 1997) |
| electrical coupling | <physiology> General term for an intimate cytoplasmic contact, mediated by gap junctions, between touching cells, such that electrical current injected into either cell changes the membrane potential of both. In neurons, arrays of gap junctions form electrical synapses, that allow action potentials to pass directly between cells. However, electrical coupling is not confined to excitable cells: many embryonic and adult epithelia are coupled, possibly to allow metabolic cooperation. (18 Nov 1997) |
| electrical diastole | Period from end of T wave to beginning of next Q wave. (05 Mar 2000) |
| electrical failure | Failure in which the cardiac inadequacy is secondary to disturbance of the electrical impulse. (05 Mar 2000) |
| electrical formula | A graphic representation by means of symbols of the reaction of a muscle to an electrical stimulus. (05 Mar 2000) |
| electrical heart position | A description of the heart's assumed electrical habitus based upon the form of the QRS complexes in leads aVL, aVF, V1, and V6. Sometimes loosely (and inaccurately) used to describe the frontal plane electric axis. Synonym: heart position. (05 Mar 2000) |
| electrical synapse | <physiology> A connection between two electrically excitable cells, such as neurons or muscle cells, via arrays of gap junctions. This allows the cells to be electrically coupled and so an action potential in one cell moves directly into the other, without the 1 ms delay inherent in chemical synapses. Electrical synapses do not allow modulation of their connection and so only occur in neuronal circuits where speed of conduction is paramount (e.g. The crayfish escape reflex). A few electrical synapses are rectifying, implying a more specialised property than a simple gap junction. (18 Nov 1997) |
| electrical systole | The duration of the QRS-T complex (i.e., from the earliest Q-wave to the end of the latest T wave on the ECG). Electromechanical systole, the period from the beginning of the QRS complex to the first (aortic) vibration of the second heart sound. Synonym: Q-S2 interval. (05 Mar 2000) |
| active transport | <biochemistry, chemistry> Transport of ions, nutrients or other molecules into a cell against a concentration gradient, this requires the expenditure of energy through ATP hydrolysis. (06 May 1997) |
| anterograde transport | Movement of material from the cell body of a neuron into axons and dendrites retrograde axoplasmic transport also occurs). (18 Nov 1997) |
| atrial transport function | The role of the atria in filling and stretching the ventricles by their presystolic contraction, without which the force of ventricular contraction and hence the cardiac output may significantly decrease. (05 Mar 2000) |
| axonal transport | Directed transport of organelles and molecules along a nerve cell axon. Transport can be anterograde (from the cell body) or retrograde (toward the cell body). (alberts et al., molecular biology of the cell, 3d ed, pg3) (12 Dec 1998) |
| axoplasmic transport | Transport by way of flow of axoplasm toward cell soma (retrograde) or toward axon terminal (anterograde). (05 Mar 2000) |
| biological transport | The movement of materials (including biochemical substances and drugs) across cell membranes and epithelial layers, usually by passive diffusion. (12 Dec 1998) |