NCIt definition : The nuclear envelope has two membranes, each with a typical unit membrane in structure.
They enclose a flattened sac and are connected at the nuclear pore sites. The inner
nuclear membrane separates the perinuclear cistern of the endoplasmic reticulum from
the nucleoplasm. It is attached to and supported by the lamina. A growing number of
proteins that are specifically located to this membrane seem to participate in functionally
organizing the nucleus. (NCI);