Streptanthus cordatus stem. Flowers occur at intervals along the upper stem. Each has a calyx of sepals roughly a centimeter long which begin greenish yellow and mature purple. Four purple petals emerge from the tip of each calyx. The fruit is a thin, narrow silique which may reach 14 centimeters in length or longer. Streptanthus cordatus Streptanthus cordatus is a species of flowering plant in the mustard family known by the common name heartleaf twistflower. It is native to the western United States, where it can be found in many types of sagebrush, woodland, and forest habitat. It is a perennial herb
Calyx of Held calcium into the mitochondria, and providing energy for glutamate synthesis. Various glial cells are also associated with the calyx of Held. Two types of glial cells surround the calyx: astrocytes and NG glial cells. The astrocytes express glutamate transporters to remove glutamate from the synapse. This is the only known mechanism for removal of glutamate from the synapse. The NG glial cells express AMPA receptors. At postnatal day two (P2), the immature calyx of Held is formed, easily distinguished by its characteristic sealed-spoon morphology. The primary synaptic contacts that form the calyx are assembled between neurons of the MNTB (medial