9/28/12 Scott

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9/28/12 Scott
2012-09-25 14:41:38

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  1. Occurs when a stem cell undergoes mitosis and divides into daughter cells
    Cellular Differentiation
  2. When this process is disrupted, the daughter cells may continue to divide with no resulting mature cell, thus causing abnormal cellular proliferation
    Cellular differentiation
  3. Cancer is a disease of the
  4. (non-reproductive cells) contain genes that promote growth and genes that suppress growth, both of which are important to control the growth of a cell.
    Somatic cells
  5. The terms for genes involved in the cancer process are
    • proto-oncogenes
    • oncogenes
    • antiongenes
  6. __________________ are the normal genes that play a part in controlling normal growth and differentiation.
  7. These genes are pre-cursors of oncogenes
  8. ______________are also called tumor-suppressor genes
  9. Note
    Inactivation of antiocogenes allows the malignant process to flourish
  10. DNA point mutations ampliification, or translocations transform a _____________ into an ____________, resulting in unrestricted cellular growth
    • proto-oncogene
    • oncogene
  11. The cell cycle is broke up into 5 phases
    G0, G1, S, G2, M
  12. 1st growth phase, RNA synthesis
  13. DNA is replicated to ensure that the resulting daughter cells will have identical genetic material
  14. 2nd growth phase, cell prepares for division
  15. cycle cycle of cellular division
    M (Mitotic phase)
  16. Cells are most sensitive to radiation during the ____ & ___ phases of the cell cycle
    G2 & M
  17. Necrosis is ________________
    Dead Tissue
  18. Note
    • Cancer cells do not die after a programmed numberof cell divisions as do normal cells.
    • Hence, cancer cells have the ability to proliferate indefinietly.
  19. Another word for undifferentiad is
  20. Tumors are divided into 2 categories
    • Benign
    • Malignant
  21. _____________ tumors are generally well differentiated and do not metastasize or invade surrounding normal tissue.
  22. Often ______________ tumors are encapsulated and slow growing
  23. _________________ are tumors that orginate from the epithelium.  These include all tissues that cover a surface or line a cavity.
  24. All processes of life occur inside the cell or plasma membrane or on its surface and are accomplished by many specialized components called ____________.
  25. Within the plasma membrane is the _________ of the cell
    containing the genetic material DNA that directs cellular metabolism.
  26. _____________ is the material from which genes are made
  27. Individual genes, which may number in the hundreds of thousands, are normally assigned specefic postions or loci on protein structures called _______________.
  28. The cell nucleus also contains one or more _______, where are organelles that facilitate ribosome assembly
  29. A _______________   ______________  encloses the nucleus.
    Nuclear membrane
  30. Between the nucleus and the otercell wall is a substance known as __________, which is a conglomerate of semi liquid material called ____________ and numerous extra nuclear organelles.
    • cytoplasm
    • cytosol
  31. _____________ are important organelles responsible for protein synthesis
  32. The ___________ ____________ is important in the storage and management of intracellular chemical substances.
    Golgi Apparatus
  33. ____________ play a role in intracellular digestion
  34. ______________ harbor specific enzyme systems, facilitating certian metabolic processes
  35. ___________________ function in cytoplasmic storage
  36. ___________ are the intracellular factories that produce adenosine triphosphate (ATP) from sugar and other organic fuels
  37. ___ ______ is the observable sequence of events pursued during hte life span of a dividing cell
    Cell Cycle
  38. 4 main phases of the cell cycle
    • G1
    • S
    • G2
    • M
  39. The shortest phase of the cell cycle is the ____ phase
    M, during which mitosis occurs
  40. Note
    The radiation therapist should be cognizant that radiation is mostly effective on cells that are actively dividing.
  41. __________ in general have 3 chemical components: a phosphate group, a molecule of sugar containing 5 carbon atoms, and a nitrogenous base.
  42. ____________ are the building blocks of life
  43. Peptide information is encoded along the DNA strand in sequences called _________.
  44. In a process called ___________ enzymes in the cell nucleus facilitate the transfer of information from a strand of DNA to a strand of RNA. (This type of RNA is called messenger RNA, mRNA)
  45. Ribosomes are the site of ____________ translation at which the message borne by the mRNA is apprehended by another type of RNA termed transfer RNA (tRNA) and is restated in the language of peptides
  46. Note
    For convenience, it is usual to classify ionizing radiations as electromagnetic or particulate.
  47. Because the majority of the cell (____%) consist of water, the probability of damage by indirect effect is much greater than for direct effects with the use of indirectly ionizing radiations
  48. note
    Low Energy Transfer (LET) radiations can be modified by physical, chemical, or biologic factors.
  49. A free radical contains an unpaired electron in the outer shell; this makes it _____________ reactive
  50. note
    Radiations can therefore be categorized by the rate at which energy is deposited by charged particles (incident or secondary) as they travel through matter
  51. __________ LET deposit their energy over great distances in tissue
  52. Densely ionizing radiations, which include charged particles such as protoons and alpha particles are classified as _____ LET
  53. ___________ LET deposit their energy over much smaller distances in the cell
  54. note
    different LET radiations produce different degrees of the same biologic response
  55. Equal doses of different LET radiations do not produce the same biologic response. This is called the ______ ________ _________ of the radiation.
    relative biologic effectiveness
  56. The ____ relates the ability of radiation with different ____ delivered under the same conditions to produce the same biologic effect
    • RBE
    • LET
  57. Gross structural changes in chromosomes are referred to as ______________, ____________, or ________________.
    • aberrations
    • lesions
    • anormalies
  58. Structural changes induced by radiation include single breaks, multiple breaks, and a phenomenon known as _____________ _____________ or _____________.
    • chromosome stickiness
    • clumping
  59. ** Note
    Approximately 95% of all single breaks heal by restitution with the results being no damage to the cell
  60. The major consequences of a double break are known as __________________ & ______________.
    • deletions
    • inversion
  61. A ___________ of genetic material results when the fragment between the breaks is lost and the remaining 2 fragments join
  62. An ____________ of genetic material result when the middle fragment with 2 broken ends turn around or inverts before rejoining the other 2 fragments
  63. Although no loss of genetic material occurs after ___________, the gene sequence is altered.
  64. The response of cells after irradaition can now be placed into 1 of 3 categories:________, _______, ________.
    • division delay
    • interphase death
    • reproductive failure
  65. note:
    The number of single breaks produced is directly proportional to the total dose of radiaiton administered.
    The frequency of single breaks, or simple aberrations, also increases as the LET of the radiation decreases.
    Therefore, low-LET radiations such as x-rays & gamma rays produce a higher amount of simple versus complex (multiple break) aberrations.
  66. Centrioles move to opposite poles of cell; spindle fibers appear and begin to orient between opposing poles
  67. Nucleoli and nuclear membrane disappears
  68. Chromosomes align across equator of spindle fibers; each pair of chromtids is attached to spindle fibers at its centomere
  69. Each cnetromere splits, thereby detaching 2 chromatids that compose each chromosome form each other.
    Sister chromatids (now called chromosomes) move to opposite poles; there are now twice as many chromosomes as there were before mitosis started
  70. Changes occuring are essentially reverse of those taking place during prophase; new chromosomes start enlongating (DNA molecules start uncoiling)
    nuclear envelop reappears, enclosing each new set of chromosomes.
    Spindle fibers disappear
  71. Irradiated cells that involve a disruption in the mitotic index (MI) the ratio of the number of mitotic cells to the total number of cells inthe irradiated population, is known as ____ ____.
    division delay
  72. Division delay is also known as
    Mitotic delay
  73. Note:
    The consequence of mitotic delay is a decrease inthe MI for the population, which means that fewer cells than normal will enter mitosis and divide. Therefore fewer new daughter cells will be produced.
    The magnitude of this response to radiation is dose dependent; the higher the radiation dose, the longer is the mitotic delay and therefore the greater is the decrease in MI
  74. If the dose is less than 1000cGy, most cell lone recovers and eventually proceed through mitosis. This results ina higher than normal number of cells dividing and is termed _____________ _______________.
    mitotic overshoot
  75. Note:
           Apparently, cells attempt to repair radiation damage before mitosis by stopping inthe G2 phase to confirm that the DNA and proteins are intact.
          Any damage found is repaired during this phase of the cell cycle so that it does not disrupt cell division or
    • possibility lead to cell death.
    •     Division delay occurs in both lethally & non-leathally damaged cells
  76. If irradiaiton of the cell during the G1, S or G2 phase results in death, this is made of response is termed an
    interphase death
  77. Interphase death is defined as the death of irrasiated cells before these cells reach mitosis, aos known as _____________ or ___________ _____________.
    nonmitotic or nondivision death
  78. VIM
    vegetative intermitoic
  79. DIM
    differentiating intermitotic
  80. RPM
    reverting postmitotic
  81. FPM
    fixed postmitotic
  82. Apoptosis is
    programmed cell death
  83. Puck & Morris invented the__________.
    survival curve
  84. The 3rd and most common end point for response of cells to radiation is _____ _____.
    • reproductive failure
    • aka mitotic death
  85. _____ ______ is defined as a decrease in the reproductive integrity or cells ability to undergo a limited number of divisions after irradiation
    reproductive failure
  86. A ____ ____ is a plot of the radiation dose admisinstered on the x-axis versus the surviving fraction (SF) of cells onthe y axis
    survival curve
  87. Various external factors influence cellular response to radiation. This change in response is termed ________ _________.
    conditional sensitivity
  88. 3 groups of factors ____, _____ and _____ can affect cellular radioresponse & therefore change the overall appearance of cell line's.
    physical, chemical & biologic
  89. Note: The response of cell to high-LET radation differs from htat seen after exposure to low LET radiation.
    2nd physical factor that influences cellular response radio-response is dose rate
  90. What are the 2 major chemical factors that influence cellular response to radiation
    radiosensitizers & radioprotectors
  91. What are chemicals that enhance response to radaition?
  92. What decreases cellular response to radiation?
  93. the most potent radiosensitizer to date is
    molecular oxygen
  94. The magnitude of the oxygen effect is termed:
    the oxygen enhancement ratio
  95. The OER compares the response of cells with radiation in the presence and _______ of oxygen
  96. The most important group of radioprotectors are ____________.
    Sulfhydryls - agents that contain sulfar (s) atom in their structure
  97. the ability of a radioprotector to diminish the effects of a dose of radiation is called the _____ _____ _____
    dose reduction factor (drf)
  98. Note:
    Cellular response is also affected by 2 important biologic factors: position in the cell cycle & ability to repair sublethal damage
  99. ____ ____ is dependant on the specific phase of the cell cycle containing the cell at all time of irradiation.
    Cellular radiosensitivity (this is also known as age response)
  100. Cells are the most sensitive in the ___ & the ___ phase
    G2 & M phase
  101. The ___ phase is the most resistant
  102. The Law of Bergonie & Tribondeau states the ____ ____ is more effective against cells that are (1) actively mitotic (2) are undifferentiated, and (3) have a long mitotic future
    ionizing radiation
  103. B&T defined ______ in ther terms of the mitotic activity & the level of differentiation.
  104. Cells dividing more often are more _____.
  105. Cells that are undifferentiate are extremely _______. These cells are also known as ___ or ______ cells.
    • radiosenstive
    • stem or precursor cells
  106. A charge in sensitivity is known as _______
    conditional sensitivity
  107. The most radiosensitive group is known as _____ _____ cells. _____ cells are rapidly dividing, undifferentiad cells with short life spans.
    • vegatative intermotic (VIM)
    • VIM
  108. The 2nd most radiosensitive group is known as ______ ______ cells.  These cells are also actively mitoticbut a little more differentiated than VIM cells
    differentiating intermitotic (DIM) cells
  109. The 3rd group cells, known as _______ _____ ______ cells, is intermediate in radiosenstivity
    multipotential connective tissue cells
  110. THe 4th group, _____ _____ _____ cells, normally do not divide but are capable of doing so.
    reverting post mitotic (RPM)
  111. The most radioresistant group of cells in the body are known as _____ _____ _____
    fixed postmitotic (FPM) cells
  112. Note: response to ionizing radiation treatment refers to visible (detectable) structural and functional changes that a dose produces in a certion period
    Reponse at all levels (whether in a cell, a tissue, an organ, a system, or the entire organism) is a function of the dose adminstered, the volume irradiated, and the time of observationafter exposure
  113. Strucutral or morphologic response after irradiation is usually grouped into 2 phases: ________ & _________.
    • early or acute changes
    • late or chronic changes
  114. early or acute changes normally happen within
    6 months of treatment
  115. late or chronic changes normally happen
    6 months or later after treatment
  116. ________ effects to the replacement of damaged cells by the same cell type
  117. _______ refers to the replacement of damaged cells by a different cell type, thus resulting in scar formation or fibrosis
  118. The most common early or acute changes after irradiation include _____, ______, and ______ ______ in the exposed area
    • inflammation
    • edema
    • possible hemorrhaging
  119. Note:  If doses are high enough, these early changes may progress to characterics late or chronic changes, include fibrosis, atrophy and ulceration.
    these late changes are not reversible & therefore are permanent