Final answer:
The nuclear lamina is the fibrous layer of proteins lining the inner nuclear membrane, providing structural support and maintaining the nucleus's shape.
Step-by-step explanation:
The fibrous layer of proteins lining the inner nuclear membrane of eukaryotic cells is called the nuclear lamina. This structure is a meshwork of intermediate filaments, primarily made up of proteins known as lamins. The nuclear lamina provides structural support to the nucleus, helping to maintain its overall shape.
It is found just inside the nuclear envelope, which consists of two phospholipid bilayers: the outer membrane and the inner membrane. The nuclear envelope is continuous with the endoplasmic reticulum, and it contains nuclear pores which control the movement of materials such as large proteins and RNA molecules into and out of the nucleus.