Rapidly proliferating non-differentiated cells are the most radiosensitive. Well known representatives of this class of cells are the stem cells of the hematopoietic tissues and the cells of the intestinal crypts. The differentiated fixed postmitotic cells are the most radioresistant.
What makes a cell radiosensitive?
Radiosensitivity is the relative susceptibility of cells, tissues, organs, organisms, or other substances to the injurious action of radiation. In general, it has been found that cell radiosensitivity is directly proportional to the rate of cell division and inversely proportional to the degree of cell differentiation .
What types of cells are most sensitive to radiation damage quizlet?
stem cells are more sensitive to radiation than mature cells. the LET of diagnostic x-rays is approximately 3 keV/μm. dose protraction and fractionation cause less effect because time is allowed for intracellular repair and tissue recovery.
Why are stem cells more radiosensitive?
Stem cell radiosensitivity is due to several signaling pathways that are activated/deactivated in response to irradiation . We believe that pluralistic interaction of molecular and epigenetic mechanisms collectively regulate and impart IR hypersensitive phenotype to the normal stem cells.
Are mature bone cells radiosensitive?
Mature bone and cartilage are relatively radioresistant because of their very slow rate of cell turnover. Because these tissues proliferate slowly and are highly differentiated, they cannot quickly repair radiation damage by repopulating.
Which part of the body is most sensitive to radiation?
Radiation in high doses can be dangerous no matter what, but some parts of the body are more sensitive than others. The most sensitive parts of the human body are the lymphoid organs, bone marrow, blood, testes, ovaries and intestines , according to the Collaboration for Nondestructive Testing[1].
Which organ is most radiosensitive?
The gastrointestinal (GI) tract is among the most radiosensitive organ systems in the body. In addition to the intestinal epithelium crypt, radiation exposure damages supporting structures such as endocrine glands of the GI tract [2].
Which tumor is most radiosensitive?
- Lymphoma.
- Myeloma.
- Seminoma.
What is the strongest ionizing radiation?
Alpha particles have approximately four times the mass of a proton or neutron and approximately ~8,000 times the mass of a beta particle (Figure 5.4. 1). Because of the large mass of the alpha particle, it has the highest ionizing power and the greatest ability to damage tissue.
Which drug is considered a radiosensitizer?
Hypoxic cell sensitizers are able to increase the radiosensitivity of tumor cells deficient of oxygen by inducing the formation and stabilization of DNA-toxic radicals, mimicking the effect of oxygen. These drugs include nitroimidazole, misonidazole, etanidazole, nimorazole, and efaproxaril .
What is the most radiosensitive part of the eye?
LENS . The lens is the most radiosensitive structure of the eye and cataract is a well recognized long-term consequence of radiotherapy.
Who is more radioresistant?
Cells that are mature, differentiated, and not actively dividing (e.g., neurons) are more radioresistant. A cell that is radiosensitive would be more inclined to die after exposure to ionizing radiation than a radioresistant cell (1).
Which human cells are the most sensitive to radiation hazwoper?
Which of the following cells are considered to be the most radiosensitive because of their reproductive rate? Blood and blood producing organ cells, immature white blood cells , digestive tract cells. Beta radiation is by far the most dangerous of the three common types of radiation.
Are bones sensitive to radiation?
Resistance to radiation has also been ascribed to bone . Older tables of roentgen-ray dosages gave for bone a dose as much as eight times that for the skin of the face. With widespread use of the more deeply penetrating hard roentgen rays, bone has been found to be not immune to injury.
Can radiation destroy cartilage?
Radiation may cause a functional decline of cartilage health in joints after exposure , contributing to arthropathy.
What are 5 effects of radiation?
| Dose (rem) Effects | 5-20 Possible late effects; possible chromosomal damage. | 20-100 Temporary reduction in white blood cells. | 100-200 Mild radiation sickness within a few hours: vomiting, diarrhea, fatigue; reduction in resistance to infection. |
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