Cell nucleus (labels) - histology illustration

Diagram of an cell nucleus:
1. Nuclear envelope
1.a. Outer membrane
1.b. Inner membrane
2. Nucleolus
3. Nuceleoplasm
4. Chromatin
4.a. Heterochromatin
4.b. Euchromatin
5. Ribosomes
6. Nuclear pore

Histlogy illustration courtesy of Mariana Ruiz.