Radiation Effects on Cells Slide 5 of 16

Go to slide: 1: Radiation Effects and Risks 2: Radiation Effects on Water 3: Radiation Effects on Water 4: Cell Structure 5: Radiation Effects on Cells 6: Radiation Effects on Cells 7: Radiation Damage and the Results 8: Cell Radiosensitivity 9: General Order of Cell Radiosensitivity 10: Limits of Exposure 11: Radiation Effects 12: Acute Radiation Syndrome 13: Risk Estimate 14: What are the chances? 15: Relative Risk 16: Doses from Various Sources

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Ionizing radiation can have two effects on living organisms, direct and indirect. Direct effects are observed through ruptured plasma membranes, disruption of mitochondria processes, release of digestive enzymes from the lysosome, etc. The cells ultimate fatality is due to a combination of all misfunctions. Generally this kind of damage results at particularly high doses ranging from 500 to 5,000 rads. Interuption of cell reproduction occurs when the nucleus has been directly impacted. The production of DNA can be delayed for a short period of time to indefinately in which case the cell dies. The range of doses at which this phenomenon occurs is highly variable. A more likely effect is chromosomal aberration. An aberration is a change in the normal shape of the chromosome. These changes are measureable after an exposure of 35 rem. Keep in mind other chemicals cause aberrations as well but radiation seems to cause particular types, deletion, ring and dicentric.* * Source: Basic Radiation Protection Technology, 1994.