| 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) |
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| 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) |
| anatomical position | The erect position of the body with the face directed forward (skull aligned in orbitomeatal or Frankfort plane); the arms at the side and the palms of the hands directed forward; the terms posterior, anterior, lateral, medial, etc., are applied to the parts as they stand related to each other and to the axis of the body when in this position. (05 Mar 2000) |
| Bozeman's position | Knee-elbow position, the patient being strapped to supports. (05 Mar 2000) |
| Valentine's position | A supine position on a table with double inclined plane so as to cause flexion at the hips; used to facilitate urethral irrigation. (05 Mar 2000) |
| mandibular hinge position | Any position of the mandible which exists when the condyles are so situated in the temporomandibular joints that opening or closing movements can be made on the hinge axis. (05 Mar 2000) |
| genucubital position | A prone position resting on the knees and elbows, assumed for gynecologic or rectal examination or operation. Synonym: genucubital position. (05 Mar 2000) |
| genupectoral position | A prone posture resting on the knees and upper part of the chest, assumed for gynecologic or rectal examination. Synonym: genupectoral position. (05 Mar 2000) |
| Casselberry position | A prone position assumed when drinking, after intubation, in order to prevent the entrance of fluid into the tube. (05 Mar 2000) |
| Mayo-Robson's position | A supine position with a thick pad under the loins, causing a marked lordosis in this region; used in operations on the gallbladder. (05 Mar 2000) |
| centric position | The position of the mandible in its most retruded unstrained relation to the maxillae. See: centric jaw relation. (05 Mar 2000) |
| rest position | The usual position of the mandible when the patient is resting comfortably in the upright position and the condyles are in a neutral unstrained position in the glenoid fossae. See: rest relation. Synonym: postural position, postural resting position, rest position. (05 Mar 2000) |
| reverse Trendelenburg position | Supine position without flexing or extending, in which the head is higher than the feet. (05 Mar 2000) |
| mentoanterior position | A cephalic presentation of the foetus with its chin pointing to the right (right mentoanterior, RMA) or to the left (left mentoanterior, LMA) acetabulum of the mother. (05 Mar 2000) |
| mentoposterior position | A cephalic presentation of the foetus with its chin pointing to the right (right mentoposterior, RMP) or to the left (left mentoposterior, LMP) sacroiliac articulation of the mother. (05 Mar 2000) |