radiosensitivity /-sen′sitiv″itē/ , the relative susceptibility of cells, tissues, organs, organisms, or any other substances to the effects of radiation. Cells of self-renewing tissues, such as those in the crypts of the intestine, are the most radiosensitive. Cells that divide regularly but mature between divisions, such as spermatogonia and spermatocytes, are somewhat less radiosensitive. Long-lived cells that usually do not divide unless there is a suitable stimulus, such as liver, kidney, and thyroid cells, are even less radiosensitive. Least radiosensitive are cells that have lost the ability to divide, such as neurons. Compare radioresistance. −radiosensitive, adj.
