(n.) A little leaf bud, as the plumule between the cotyledons.
(n.) One of the buds of mosses.
(n.) One of the reproductive spores of algae.
(n.) An ovule.
(n.) A bud produced in generation by gemmation.
(n.) One of the imaginary granules or atoms which, according to Darwin's hypothesis of pangenesis, are continually being thrown off from every cell or unit, and circulate freely throughout the system, and when supplied with proper nutriment multiply by self-division and ultimately develop into cells like those from which they were derived. They are supposed to be transmitted from the parent to the offspring, but are often transmitted in a dormant state during many generations and are then developed. See Pangenesis.
Example Sentences:
(1) In the external plexiform layer, a reduced number of mature dendrodendritic synapses and signs of harmed granule gemmules were observed.
(2) F1 knobs contain flattened synaptic vesicles and form symmetrical junctions with F2 knobs, gemmules, spines, and small-medium dendrites in synaptic islands, throughout the neuropil, and on the proximal dendrites and soma of the largest type of neuron.
(3) In electron micrographs of the external plexiform layer, the gemmules which arise from the distal dentrites of granule cells were also observed to be filled with reaction product, and these structures corresponded in size and location to the puncta observed in light microscopic preparations.
(4) Gametogenesis occurs shortly after gemmule hatching in both males and females but slightly later in males.
(5) F2 knobs are irregularly shaped, contain pleiomorphic synaptic vesicles and make symmetrical junctions primarily with gemmules and spines in synaptic islands.
(6) An excess of thyroid hormones therefore causes neuronal proliferation to end precociously leading to a reduction of the total number of gemmules.
(7) Cellular fragments phagocyted by the thesocytes during the gemmule formation undergo a condensation and rearrangement of their constituent elements before forming a definitive platelet.
(8) It has recently been claimed by Ramon-Moliner29, that reciprocal synapses between mitral (and tufted) cell dendrites and granule cell gemmules, which for more than 10 years have been thought to represent a major feature of the structural and functional organization of the olfactory bulb28, are non-existent or, at best, extremely rare.
(9) They are found primarily in "synaptic islands" making contact with gemmules, spines, small dendrites, and other synaptic profiles containing pleiomorphic synaptic vesicles (F2).
(10) The gemmules were observed to form reciprocal dendrodentritic synaptic junctions with mitral cell dentrites which lacked reaction product.
(11) Hypothyroidism may lead to cellular hypoplasia and reduced dendritic ramification, gemmules and interneuronal connections.
(12) They migrate with their growth cones oriented toward the olfactory bulb from the level of the anterior lateral ventricle into the granular layer of the olfactory bulb, where they differentiate into the definitive granule cells: their somata enlarge; the leading processes elongate, branch, sprout many gemmules, and become the peripheral processes; and the trailing processes become the basal dendrites.
(13) It is suggested that a granule-to-mitral dendro-dendritic synapse only forms next to an already existing mitral-to-granule synapse on the same gemmule.
(14) The large amount of geographic overlap of retinal and cortical terminals on gemmules, spines, and small dendrites found in the neuropil outside of synaptic islands logically would maximize axonal sprouting between these two sources.
Pangenesis
Definition:
(n.) An hypothesis advanced by Darwin in explanation of heredity.