Unit 3 Cell and Tissue Response to Radiation

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  1. a cell that is specialized functionally and/or morphologically
    can be mature cell or end cell in a population
  2. cell that is not specialized.
    immature cell whose primary function is to divide
  3. three categories of cells
    • stem cells
    • transit cells
    • static cells
  4. -cyte =
    -blast =
    • -cyte = mature
    • -blast = immature
  5. stem cells primary function is to divide to:
    • maintain its own population
    • produce cells for another population
  6. stems cells are
  7. basal cells of epidermis
    myoblast of bone marrow
    osteoblast in the bone
    intestinal crypt cells

    used to treat severely burned patients
    stem cells
  8. cells that are on their way from the stem cell compartment to the mature cell compartment
    transit cells
  9. 5 cell populations
    • vegitative intermitotic cells (VIM)   LEAST MATURE
    • differentitating intermitotic cells (DIM)
    • multipotential connective cells
    • reverting postmitotic cells (RPM)
    • fixed postmitotic cells (FPM) MOST MATURE
  10. cell populations were defined by
    • Dr. Robert J Rubin
    • Dr. David Casarett
  11. rapidly dividing undifferentiated cells that have a short lifetime
    most radiosensitive
    vegetative intermitotic cells (VIM)
  12. examples of VIM
    • basal cells
    • crypt cells
    • type A sperm
    • erythroblasts
  13. cells produced by the division of VIM cells.
    actively mitotic but more differentiated than VIM.
    more radioresistant thatn VIM
    differentiating intermitotic cells (DIM)
  14. examples of DIM
    intermediate and B type sperm
  15. cells divide irregularly and are more differentiated than DIM cells
    more radioresistant than DIM
    Multipotential connective cells
  16. examples of multipotential connective cells
    • endothelial cells (line blood vessels)
    • fibroblasts (connective tissue)
  17. cells that do not normally divide, however, they retain the ability to divide under certain circumstances.
    more differentiated and usually long lived
    reverting postmitotic cells (RPM)
  18. reverting postmitotic cells are more radioresistant except
  19. examples of RPM
    • liver cells
    • mature lymphocytes
  20. cells do not divide and are highly differentiated
    most radioresistant
    fixed postmitotic cells FPM
  21. examples of FPM
    • nerve cells
    • muscle cells
    • erythrocytes (RBC)
    • spermatozoa
  22. types of cell damage
    • reproductive death
    • mitotic or genetic death
    • interference of function
    • interphase death
    • mitotic delay
    • chromosomal breakage
  23. cell permanently loses it ability to reproduce
    cells lives continuing to metabolize and synthesize nucleic acids and protein
    100-1000 rads (1-10 Gy)
    reproductive death
  24. when a cell has been irridated and dies without attempting division
    governed by radiosensitivity of cell
    more radiosensitive=smaller dose required
    • interphase death
    • aka nonmitotic death
    • aka nondivision death
  25. interphase death for cells in hemopoetic system would require                        than central nervous system cells
    less dose
  26. interphase death for radiosensitive cells such as lymphocytes or spermatogonia requires                    cGy (rad), where interphase death for more radioresistant cells such as those in bone requires                   cGy (rad)
    • a few hundred
    • several thousand
  27. occurs when a cell dies after one or more divisions. can be caused by small doses of radiation. mitotic process is slowed or permanently inhibited. cell death can occur after permanent inhibition
    mitotic or genetic death
  28. the radiation dose required to produce mitotic death is            than the dose needed to produce interphase death in slowl dividing cells or in non-dividing cells
  29. failure of a cell to start dividing on time.
    can result from as little as         Gy (rad)
    • mitotic delay
    • 0.01 Gy (1 rad)
  30. permanent or temporary                                      idependent of the cell's ability to divide can occur as a result of exposure to ionizing radiation.
    if repair enzymes can fix the damage. the cell can recover and continue to function.
    interference of function
  31.                      occurs when:
    ionizing radiation interacts directly with many DNA molecules (direct effect)
    free radicals interact with DNA with many DNA molecules (inderect effect)
    chromosome breakage
  32. since chromosome breakage may result in a loss of genetic material this can lead to                                in the future generations
    genetic mutations
  33. the study of genetics of cells in particular cell chromosomes
  34. when damage to DNA is severe (breakage of many bonds and strands) the chromosome may be fragmented
    chromosome breaks
  35. for a cell to die following radiation exposure, its target molecule must be inactivated
    Target theory
  36. experimental evidence suggests that the target molecule is         and that there is                            of radiation to the target molecule
    • DNA
    • no favoritism
  37. Effect
     Blood count changes

    Vomiting (threshold)

    Mortality (threshold)
    LD50/60 (with minimal supportive care)

    LD50/60 (with supportive medical treatment)
    100% mortality (with best available treatment)
    • Dose
    •  50 rem

    •  100 rem
    • 150 rem

     320-360 rem

     480-540 rem

     800 rem
  38. a method of displaying th eradiation sensitivity of a particular cell type                  and are plotted            
    • cell survival curve
    • in vitro
  39. in glassware or an artificial environment, outisde the living body
    in vitro
  40. in the living body
    • in vivo
    • (more accurate)
  41. in vitro assays:
    • cells harvested from culture and plated out
    • dishes are irridated at different levels
    • the number of colonies are counted after a specific time
    • number of colonies compared to control sample
    • survival curves generated
  42. single target, single hit applies to:
    • enzymes
    • viruses
    • bacteria
    • other simple cells
    • (no survival curve)
  43. multi target, single hit applies to:
    • human cells
    • mammalian cells
  44. the radiation dose sufficient to kill 63% of the cells. (37% surviving).
  45. quais-threshold dose. the width of the shoulder region of a cell survival curve
  46. determined by extrapolation of the linear portion of the curve back to its intersection with the y axis
    extrapolation number
  47. an expression of radiosensitivitym, mean lethal dose. dose required to reduce cells surviving to 37% o nthe multi target single hit model.
  48. the lower the D0 the more               the cell
  49. factors affecting radiation response.
    • physical
    • biological
    • chemical
  50. energy transfer per length of travel (keV/micrometer)
    higher LET produces higher response
  51. alpha and beta are               LET
    xray and gamma are                  LET
    • high
    • low
  52. dose of standard radiation (200-250 kvp) to produce an effect compared to the dose of test radiation to produce the same effect
    Higher           = greater response
  53. dose delivered continuously but at a lower dose rate
    allows for higher overall doses to be achieved which is helpful when treating cancer
  54. dose delivered approx the same time each day but over a course of several days or weeks.
    lowers radiation response but allow for good cells to repair
  55. the vast majority of intracellular repair is finished by           post irridation
    6 hours
  56. tissue is more sensitive to radiation when irridated in the oxygenated state than when irridated under anoxic or hypoxic conditions
    oxygen effect
  57. dose necessary under anoxic condition to produce a given effect divided by dose necessary under aerobic conditions to produce the same effect
  58. oxygen            radiation response
  59.                         are more sensitive than middle age if considering age only
    infants and geriatrics
  60.           are more sensitive than               
    this high tolerance is thought to be contributed to what?
    • males
    • females
    • hormones(estrogen)
  61. very sensitive cells need                        time than less sensitive cells
    more recovery
  62. dose given in a short span of time as oppesed to a long span will require                time
    more recovery
  63. malnourishment                  the probabiblity of radiation response
  64. undifferentiated cells are            sensitive and divide                
    • more
    • faster
  65. differentiated cells are                sensitive and divide               
    • less
    • slower
  66.                      is more sensitive than mitotic
  67. drugs used to protect against ionizing raditation:
  68. drugs used to increase the effectiveness of radiation therapy in destroying unwanted cells
    • radiation sensitizers
    • (chemo drugs)
  69. ionizing radiation is more effective against cells that are actively mitotic, undifferentiated, and have a long dividing future
    law of bergonie and tribondeau
  70. cells with high radiosensitivity
    • lymphoid organs
    • bone marrow
    • blood
    • testes
    • ovaries
    • intestines
  71. cells with fairly high radiosensitivity
    skin and other organs with epitheleal cell lining (cornea, oral cavity, esophagus, rectum, bladder, vagina, uterine, cervix, ureters)
  72. cells with moderate radiosensitivity
    • optic lens
    • stomach
    • growing cartilage
    • fine vasculature
    • growing bone
  73. cells with fairly low radiosensitivity
    • mature cartilage or bones
    • salivary glands
    • respiratory organs
    • kidneys
    • liver
    • pancreas
    • thyroid
    • adrenal and pituitary gland
  74. cells with low radiosensitivity
    • muscle
    • brain
    • spinal cord
Card Set:
Unit 3 Cell and Tissue Response to Radiation
2015-03-16 17:46:02
Radiation biology

Radiation Biology
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