| synaptic conduction | The conduction of a nerve impulse across a synapse. (05 Mar 2000) |
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| synaptic | <physiology> Pertaining to or affecting a synapse or synapsis. (10 Jan 1998) |
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| synaptic 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) |
| synaptic cleft | <physiology> The narrow space between the presynaptic cell and the postsynaptic cell in a chemical synapse, across which the neurotransmitter diffuses. (10 Jan 1998) |
| synaptic endings | 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) |
| synaptic membranes | Cell membranes associated with synapses. Both presynaptic and postsynaptic membranes are included along with their integral or tightly associated specializations for the release or reception of transmitters. (12 Dec 1998) |
| synaptic phase | <cell biology> The specific pairing of the chromatids of homologous chromosomes during prophase I of meiosis. It allows crossing over to take place. (18 Nov 1997) |
| synaptic resistance | The ease or difficulty with which a nerve impulse can cross a synapse. (05 Mar 2000) |
| synaptic terminals | 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) |
| synaptic transmission | <physiology> The process of propagating a signal from one cell to another via a synapse. (10 Jan 1998) |
| synaptic vesicle | <cell biology> Intracellular vesicles found in the presynaptic terminals of chemical synapses, which contain neurotransmitter. During activity the vescles release their contents at the synapse and the neurotransmitter stimulate receptors on other cells. (10 Jan 1998) |
| synaptic vesicles | Membrane-bound compartments which contain transmitter molecules. Synaptic vesicles are concentrated at presynaptic terminals. They actively sequester transmitter molecules from the cytoplasm. In at least some synapses, transmitter release occurs by fusion of these vesicles with the presynaptic membrane, followed by exocytosis of their contents. (12 Dec 1998) |
| aberrant ventricular conduction | Abnormal intraventricular conduction of a supraventricular beat, especially where surrounding beats are normally conducted. Synonym: ventricular aberration. (05 Mar 2000) |
| accelerated conduction | Any pathologically increased speed of conduction; usually occurs between the atrium and ventricles as in the Wolff-Parkinson-White and Lown-Ganong-Levine syndromes; such accelerated pathways provide the bases for particular forms of reentry tachycardia. (05 Mar 2000) |
| A-H conduction time | Forward conduction of the cardiac impulse from atria to ventricles via the A-V node or any bypass tract, represented in the electrocardiogram by the P-R interval. P-H conduction time is from the onset of the P wave to the first high frequency component of the His bundle electrogram (normally 119 ± 38 msec); A-H conduction time is from the onset of the first high frequency component of the atrial electrogram to the first high frequency component of the His bundle electrogram (normally 92 ± 38 msec); P-A conduction time is from the onset of the P wave to the onset of the atrial electrogram (normally 27 ± 18 msec). (05 Mar 2000) |
| air conduction | In relation to hearing, the transmission of sound to the inner ear through the external auditory canal and the structures of the middle ear. (05 Mar 2000) |