synapsis(redirected from synaptic phase)
Also found in: Dictionary, Thesaurus, Encyclopedia.
the pairing off and union of homologous chromosomes from male and female pronuclei at the start of meiosis.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
The point-for-point pairing of homologous chromosomes during the prophase of meiosis.
Synonym(s): synaptic phase
[G. a connection, junction]
Farlex Partner Medical Dictionary © Farlex 2012
n. pl. synap·ses (-sēz)
The side-by-side association of homologous chromosomes during the first prophase of meiosis.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
The functional membrane-to-membrane contact of the nerve cell with another nerve cell, an effector (muscle, gland) cell, or a sensory receptor cell. The synapse subserves the transmission of nerve impulses, commonly from a club-shaped axon terminal (the presynaptic element) to the circumscript patch of the plasma membrane of the receiving cell (the postsynaptic element) on which the synapse occurs. In most cases, the impulse is transmitted by means of a chemical transmitter substance (such as acetylcholine, gamma-aminobutyric acid, dopamine, norepinephrine) released into a synaptic cleft that separates the presynaptic from the postsynaptic membrane; the transmitter is stored in synaptic vesicles in the presynaptic element. In other synapses, transmission takes place by direct propagation of the bioelectrical potential from the presynaptic to the postsynaptic membrane.
[syn- + G. hapto, to clasp]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
- the lying together of structures as in, for example, the junction of two nerve cells.
- (in genetics) the pairing of HOMOLOGOUS CHROMOSOMES in prophase 1 of MEIOSIS; the alignment of homologous regions of DNA prior to RECOMBINATION in prokaryotes.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005