Cell death is when a cell ceases to carry out its functions. Kinds of cell death include:
1. Programmed cell death (PCD), which is when a intracellular program carries out a regulated process to kill the cell. Usually it is good for the organism. For example, the differentiation of fingers and toes in the human embryo occurs because cells between the fingers apoptose. PCD has fundamental functions in tissue development. There are 2 forms of PCD: apoptosis and autophagy.
a. Apoptosis occurs in multicellular organisms. Biochemical events lead to cell changes and death. Some of the changes include blebbing*, cell shrinkage, the nucleus falling apart, chromatin condensing and DNA falling apart. Sometimes it is called "cell suicide".
b. Autophagy is characterized by the formation of large vacuoles that "eat away" the organelles in a specific sequence before the nucleus is destroyed. It is generally activated in conditions of nutrient deprivation, but is also associated with physiological and pathological processes, such as development, differentiation, neurodegenerative diseases, stress, infection and cancer.
Other pathways of programmed cell death have also been also been discovered, but are less well studied.
2. Necrosis is cell death as a result of infection or injury. It is caused by external factors, such as trauma or infection and occurs in different forms.
3. Ischemic cell death is a form of accidental cell death that is characterized by mitochondrial swelling and swelling of the nucleus.
4. Immunogenic cell death is cause by cytostatic agents (compounds that inhibit cell growth or multiplication)
*When a cell detaches its cytoskeleton form the membrane cause the membrane to swell into a spherical bubble. It is useful when the cell is about to divide or in apoptosis.
If you are familiar with the concept of programmed cell death and that apoptosis is a form of it, then this is probably sufficient information ;-)
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