Pyknosis

Morphological characteristics of pyknosis and other forms of nuclear destruction

Apoptosis

Pyknosis, or karyopyknosis, is the irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis^[1] or apoptosis.^[2] It is followed by karyorrhexis, or fragmentation of the nucleus. Pyknosis (from Greek pyknono meaning "to thicken up, to close or to condense") is also observed in the maturation of erythrocytes (a red blood cell) and the neutrophil (a type of white blood cell). The maturing metarubricyte (a stage in RBC maturation) will condense its nucleus before expelling it to become a reticulocyte. The maturing neutrophil will condense its nucleus into several connected lobes that stay in the cell until the end of its cell life.

Pyknotic nuclei are often found in the zona reticularis of the adrenal gland.

See also

• Apoptosis
• Karyolysis

References

1. ^ Kumar V, Abbas A, Nelson F, Mitchell R. (2007). "Robbins Basic Pathology". Robbins Basic Pathology: 6, 9–10. 
2. ^ Kroemer G, Galluzzi L, Vandenabeele P, et al. (January 2009). "Classification of cell death: recommendations of the Nomenclature Committee on Cell Death 2009". Cell Death Differ. 16 (1): 3–11. doi:10.1038/cdd.2008.150. PMC 2744427. PMID 18846107. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2744427.