News tagged with apoptosis
Related topics: cell death
Apoptosis ( /ˌæpəˈtoʊsɪs/) is the process of programmed cell death (PCD) that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation. (See also Apoptosis DNA fragmentation.) Unlike necrosis, apoptosis produces cell fragments called apoptotic bodies that phagocytic cells are able to engulf and quickly remove before the contents of the cell can spill out onto surrounding cells and cause damage.
In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis, in general, confers advantages during an organism's life cycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. Between 50 and 70 billion cells die each day due to apoptosis in the average human adult. For an average child between the ages of 8 and 14, approximately 20 billion to 30 billion cells die a day.
Research in and around apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes atrophy, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
Many medical issues affect nerves, from injuries in car accidents and side effects of chemotherapy to glaucoma and multiple sclerosis. The common theme in these scenarios is destruction of nerve axons, the ...
Neuroscience May 09, 2013 | 5 / 5 (1) | 0 |
(Medical Xpress)—Membrane fusion is a highly regulated event, both inside cells, and between them. From the moment a sperm first fuses with an egg, subsequent developmental events depend upon its proper ...
Medical research Apr 26, 2013 | 4.3 / 5 (3) | 0 |