Narcissus (plant) corona. Floral tubes can range from long and narrow in sections "Apodanthi" and "Jonquilla" to rudimentary ("N. cavanillesii"). Surrounding the floral tube and corona and reflexed (bent back) from the rest of the perianth are the six spreading tepals or floral leaves, in two whorls which may be distally ascending, reflexed (folded back), or lanceolate. Like many monocotyledons, the perianth is homochlamydeous, that is undifferentiated into separate calyx (sepals) and corolla (petals), but rather has six tepals. The three outer tepal segments may be considered sepals, and the three inner segments petals. The transition point between the floral tube and
Calyx of Held of Held has been used to understand a variety of mechanisms related to development of, and vesicle release of the synapse. The calyx of Held is a part of the auditory system, connecting the globular bushy cells (GBCs) of the anteroventral cochlear nucleus to the principal neurons of the medial nucleus of the trapezoid body (MNTB). As a synapse, the function of the calyx of Held is to transmit the signal from the GBCs to the principal neurons. The principal neurons of the MNTB are glycinergic, thus hyperpolarizing the superior olivary complex (SOC) nuclei in nearby cells and producing tonotopic