Plant cell the major classes of cells and tissues of roots, stems, leaves, flowers, and reproductive structures, each of which may be composed of several cell types. Parenchyma cells are living cells that have functions ranging from storage and support to photosynthesis (mesophyll cells) and phloem loading (transfer cells). Apart from the xylem and phloem in their vascular bundles, leaves are composed mainly of parenchyma cells. Some parenchyma cells, as in the epidermis, are specialized for light penetration and focusing or regulation of gas exchange, but others are among the least specialized cells in plant tissue, and may remain totipotent, capable of
Inner nuclear layer a flat cone form and take signals from seven cones. The bipolar cells corresponds to the intermediary cells between the touch and heat receptors on the skin and the medulla or spinal cord. The horizontal cells lie in the outer part of the inner nuclear layer and possess somewhat flattened cell bodies. Their dendrites divide into numerous branches in the outer plexiform layer, while their axons run horizontally for some distance and finally ramify in the same layer. The amacrine cells are placed in the inner part of the inner nuclear layer, and are so named because they have not