Apoptosis is a type of programmed cell death that occurs in various situations, such as in normal and pathological organogenesis and hematopoiesis, physiological replacement of certain tissues, in organ atrophy, inflammatory response and elimination of cells after cell damage by genotoxic and pathological agents mild and also during metamorphosis. apoptosis in biology
Cell death was originally classified as apoptosis and necrosis, however, other forms of cell death have now been described, such as autophagic, cornification, parapoptosis, and catastrophic mitosis. apoptosis in biology
The term apoptosis was first used in 1972 by scientists Kerr, Wyllie, and Curie.
During the apoptosis process, the cell undergoes a series of morphological changes such as a decrease in size and volume and loss of contact with the extracellular matrix and neighboring cells. apoptosis in biology
The cell nucleus undergoes a series of changes, the chromatin begins to condense forming thick clumps of heterochromatin, then migrates towards the periphery, concentrating near the nuclear envelope, leaving the nucleus with an irregular shape; During the chromatin condensation process, DNA undergoes sonic internucleus fragmentation by the action of endonucleases, forming fragments with a characteristic pattern. These DNA fragments have variable size, but are always found in multiples of 200 base pairs. apoptosis in biology
After condensation and marginalization of chromatin, the nucleus breaks apart to form spheres called heterochromatic corpuscles.
The organelles present in the cytoplasm are packed by the endoplasmic reticulum and vacuolations can occur.
Due to the degradation of the nucleus, the cytoskeleton undergoes a rupture and the cell loses its original shape. Intracellular transport is also damaged and the cell retracts. There is the formation of cytoplasmic processes called bullae with the release of apoptotic cells after being phagocytosed by neighboring cells, tissue macrophages, or macrophages in cavities associated with the epithelium.
Apoptosis can be triggered by several factors: binding of molecules to membrane receptors, chemotherapeutic agents, ionizing radiation, DNA damage, heat shock, lack of growth factors, low amounts of nutrients, and increased levels of reactive oxygen species ( ROS). apoptosis in biology
The apoptosis activation process involves a series of proteins called pro-apoptotic, antiapoptotic, and caspase proteins.
The study of apoptosis is very important to understand the mechanisms of control and maintenance of the body and different diseases, such as cancer.
The better knowledge of apoptosis allowed the development of new alternatives for the control and cure of various tumors by inducing death in tumor cells. apoptosis in biology