1. The nucleus: Nuclear envelope and npc A. Structure: Double-membrane nuclear envelope surrounds the nucleus Nuclear lamina lucien enve nner nuclear Nucleolus embrane Chromatin Perinuclear space SeNUCLEOPLAS Figure 16-26 The Structural Organization of the Nucleus and Nuclear pores Nuclear Envelope. (a) An electron micrograph of the nucleus frum a mouse liver cell, with prominent structutal features labeled(TEM The CYTOSOL nuclear envelope is a doutle membrane perforated ty iclear pores INP) Internal structures include the nucleolus nu), euchromatin (eu), and heterochromatin (he).(b)A drawing of a typical nucleus Structural Rough ER features included here but not visible in he micrograph include the nuclear lamina niosomes on the outer nuclear membrane. and the continuity between the outer nuclear membrane and the rough ER1. The nucleus: Nuclear envelope and NPC A. Structure: Double-membrane nuclear envelope surrounds the nucleus