Calyx (anatomy) kidney, a conglomeration of two or three minor calyces to form a major calyx, or the Calyx of Held, a particularly large synapse in the mammalian auditory central nervous system, named by H. Held in his 1893 article "Die centrale Gehörleitung", due to its flower-petal-like shape. In male insects, a funnel-shaped expansion of the basal part of the "vas deferens" (part of the seminal duct). Also in entomology, a flattened cap of neuropile in an insect brain (a component of the corpus pedunculatum) and by certain female insects, an expansion of the oviduct into which the ovarioles open. Calyx (anatomy)
Calyx of Held a mature calyx that facilitates the consistent, rapid spread of signals in the MNTB-VCN area. A select few processes occur during early neuronal development in order to ensure proper calyx formation, specifically through the influence of Fibroblastic Growth Factor (FGF), transcription factor Math5, neural cell recognition molecule NB-2, and ephrin (Eph) proteins in cells. Math1/Math5 and FGF are two regulators essential for appropriate growth and development of the cochlear nucleus complex, which comprises both the ventral cochlear nucleus (VCN) and the dorsal cochlear nucleus (DCN). Sufficient FGF levels ensure proper morphology of the cochlear nuclei, while Math5 insures correct size