The Nucleus

Nucleus

Found in all cells except Red Blood Cells

Archive of the cell; source of our ribosomal, messenger, and transfer RNA; Performs synthetic and metabolic functions

Functions of the nucleus

Vesicular, Segmented, Anucleated, Multi-nucleated, Multi-lobulated, Chromatic, Pyknotic

Types of nuclei

Vesicular

Type of this nucleus means that there are intense metabolic activities in the cell

Euchromatin

Vesicular nuclei contain this form of chromatin

2 Segments

Eosinophils have this many segments in their nucleus

3-5

White blood cells have this many segments in their nucleus

Multinucleated

Type of cell with multiple peripheral nuclei

Skeletal Muscle Cells

Cells that are multinucleated and the nuclei are scattered and located peripherally

Osteoclasts

Cells that are multinucleated but the nuclei are clustered together

Multi-lobulated nucleus

Single-nucleus but has many lobes

Megakaryocytes

Example of multi-lobulated nucleus

Chromatic Nucleus

Dark Staining nucleus

Pyknotic Nucleus

VERY dark staining nucleus

Cells that are dying

Cells that pyknotic nuclei are present

Nuclear Membrane

Separates the nucleus from the cytoplasm

35 nm

Thickness of the nuclear membrane

Nuclear Chromatin

Contains DNA and Proteins

Heterochromatin and euchromatin

2 types of chromatin

Heterochromatin

Dark-staining chromatin; metabolically inert

Euchromatin

Pale-staining Chromatin; Metabolically active

Nucleolus

Site of synthesis of ribosomal RNA and ribosomal assembly

Dense Fibrillar Components, Paler Fibrillar Centres, Granular Component

3 regions of the Nucleolus

Dense fibrillar components

Region of the nucleolus for the site of ribosomal RNA synthesis

Granular Component

Region of the nucleolus for ribosomal assembly

Chromosomes

May show irregular densities of staining along their lengths

Barr Bodies

Small visible mass in the inner portion of a nuclear membrane in females