The<unk>  (also known as the perinuclear<unk> ,<unk>  membrane, nucleolemma or karyotheca) is the double membrane of the nucleus that encloses genetic material in eukaryotic cells. It separates the contents of the nucleus (DNA in particular) from the cytosol (cytoplasm).
Numerous<unk>  pores are present on the<unk>  to facilitate and regulate the exchange of materials (for example, proteins and RNA) between the nucleus and the cytoplasm.
The space between the two membranes that make up the<unk>  is called the perinuclear space (also called the perinuclear cisterna), and is usually about 20 - 40 nm wide. Each of the two membranes is composed of a lipid bilayer.  The outer membrane is continuous with the rough endoplasmic reticulum.
The inner membrane is erected upon the<unk>  lamina, a<unk> twork of intermediate filaments made of lamin, that plays a role in mitosis and meiosis. The type of lamins present are A, B1, B2, and C.
The<unk>  may also play a role in the disposition of chromatin inside the nucleus. The lamina acts as a site of attachment for chromosomes. It also acts like a shield for the nucleus.
Nuclear envelope
Golgi apparatus
Cytoskeleton
Sarcomere
Cell junction
Cytome
Centromere
Mitochondrion