Glossary of plant morphology flowers, a tube or cup-like hypanthium (floral tube) is formed above or around the ovary and bears the sepals, petals, and stamens. There may also be a nectary producing nectar. Nectaries may develop on or in the perianth, receptacle, androecium (stamens), or gynoecium. In some flowers nectar may be produced on nectariferous disks. Disks may arise from the receptable and are doughnut- or disk-shaped. They may also surround the stamens (extrastaminal), be at the stamen bases (staminal), or be inside the stamina (intrastaminal). Finally, the actual reproductive parts form the innermost layers of the flower. These leaf primordia become specialised
Calyx of Held The first is that in the second week of development, myelination of the VCN axons in the MNTB increases. This prominent growth in myelin corresponds to the chronological development of the signaling circuit and adaptation of the calyx. The second ultrastructural change involves the principal neurons of the MNTBs, whose cell bodies and nuclei increase in surface area due to enlargement. This is a direct result of individual, larger postsynaptic densities breaking up into smaller, multiple densities. Potassium channels are vital in conducting the presynaptic action potential. The calyx contains several types of potassium channels, each differing in location and