Radiation and Cellular Damage
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Questions and Answers

What is the main reason why lymphocytes are the most sensitive to radiation?

  • They are not regenerating as quickly
  • They are the only cells that can reproduce
  • They are the largest cells in the body
  • They are constantly regenerating (correct)

    • What happens to cells that are damaged by radiation but can still reproduce?

  • They stop reproducing
  • They become mutated and reproduce (correct)
  • They die immediately
  • They completely repair the damage

    • Which of the following organs is the least sensitive to radiation?

  • Blood-forming organs
  • Skin
  • Reproductive and gastrointestinal tract organs
  • Muscle and brain (correct)

    • What is the result of severe radiation damage to cells?

    <p>The cell dies</p> Signup and view all the answers

    What is the correlation between the sensitivity of organs and cells?

    <p>The sensitivity of organs correlates with the relative sensitivity of the cells from which they are composed</p> Signup and view all the answers

    What is the name of the process by which cells can repair radiation damage?

    <p>Repair</p> Signup and view all the answers

    What is the potential outcome of a mutated cell reproducing?

    <p>The beginning of a malignant tumour</p> Signup and view all the answers

    How are the biological effects of radiation typically divided?

    <p>Into acute and chronic effects</p> Signup and view all the answers

    What is the main difference between high doses and low doses of radiation?

    <p>High doses tend to kill cells, while low doses tend to damage or change them</p> Signup and view all the answers

    What might occur when tissues and organs are damaged due to high doses of radiation?

    <p>A rapid whole-body response often called the Acute Radiation Syndrome (ARS)</p> Signup and view all the answers

    What is the effect of low doses of radiation spread out over long periods of time on body organs?

    <p>It doesn't cause an immediate problem to any body organ</p> Signup and view all the answers

    What is the effect of high doses of radiation on cells?

    <p>It kills cells</p> Signup and view all the answers

    What is the effect of low doses of radiation on cells?

    <p>It damages cells</p> Signup and view all the answers

    At what dose of radiation (in Rad) do blood count changes occur in an individual?

    <p>100</p> Signup and view all the answers

    At what dose of radiation (in Rad) does vomiting occur?

    <p>150</p> Signup and view all the answers

    What is the term for the dose of radiation that would be fatal to 50% of the population within 60 days?

    <p>LD 50/60</p> Signup and view all the answers

    What is the threshold value in the table?

    <p>The dose at which the effect is first observed in the most sensitive of the individuals exposed</p> Signup and view all the answers

    What is the main reason why some people die while others survive after being exposed to the same radiation dose?

    <p>Their ability to combat the incidental effects of radiation exposure</p> Signup and view all the answers

    What is the effect of radiation on the skin that requires a dose in excess of 1,200 rad?

    <p>Moist desquamation</p> Signup and view all the answers

    What is the dose required for red-haired loss to occur?

    <p>About 500 rad</p> Signup and view all the answers

    What is the effect of radiation that appears to have a threshold of about 200 rad?

    <p>Cataracts</p> Signup and view all the answers

    What is the dose required to produce permanent sterility in males?

    <p>In excess of 400 rad</p> Signup and view all the answers

    What is the effect of radiation that is more likely to occur with exposure to low energy gamma-ray, or beta radiation?

    <p>Skin effects</p> Signup and view all the answers

    What is the term for the lethal dose at which 50% of those exposed to that dose will die within 60 days?

    <p>LD 50/60</p> Signup and view all the answers

    What is the primary source of biological effects caused by radiation?

    <p>Interaction with atoms</p> Signup and view all the answers

    What is the term used to describe the effect of radiation on the DNA molecule or other critical cellular components?

    <p>Direct effect</p> Signup and view all the answers

    What makes up the majority of a cell's volume?

    <p>Water</p> Signup and view all the answers

    What is the ultimate outcome of radiation interacting with the DNA molecule or critical cellular components?

    <p>Cellular death</p> Signup and view all the answers

    What is the probability of radiation interacting with the DNA molecule?

    <p>Very low</p> Signup and view all the answers

    What is the term used to describe the effect of radiation on cellular components other than DNA molecules?

    <p>Indirect effect</p> Signup and view all the answers

    What is the primary mechanism by which radiation affects cells?

    <p>Both direct and indirect effects</p> Signup and view all the answers

    What is the ultimate outcome of radiation interaction with atoms?

    <p>Cellular damage</p> Signup and view all the answers

    Why are neutrons effective in producing cataracts?

    <p>Because the eye has a high-water content</p> Signup and view all the answers

    What is the primary result of the Somatic effect of radiation exposure?

    <p>Cancer</p> Signup and view all the answers

    Which category of effects of radiation exposure is suffered by the offspring of the individual exposed?

    <p>Genetic</p> Signup and view all the answers

    What is the In-Utero effect of radiation exposure?

    <p>A special case of the somatic effect</p> Signup and view all the answers

    How many categories of effects are resulting from exposure to low doses of radiation?

    <p>3</p> Signup and view all the answers

    What is the primary difference between the Genetic and Somatic effects of radiation exposure?

    <p>The individual affected</p> Signup and view all the answers

    Study Notes

    Types of Cellular Damage due to Radiation

    • Radiation causes ionizations of atoms, which may affect molecules, cells, tissues, organs, and the whole body.
    • There are two mechanisms by which radiation ultimately affects cells: direct and indirect effects.

    Direct Effect

    • Radiation interacts with the atoms of the DNA molecule or some other cellular component critical to the survival of the cell.
    • Such interaction may affect the ability of the cell to reproduce and survive.
    • If enough atoms are affected, the cell may be destroyed by "direct" interference with its life-sustaining system.

    Indirect Effect

    • Radiation interacts with the water that makes up most of the cell's volume.
    • This interaction can lead to the formation of free radicals, which can damage the cell's DNA and other components.

    Cell Sensitivity

    • Lymphocytes (white blood cells) and cells that produce blood are constantly regenerating and are the most sensitive to radiation.
    • Reproductive and gastrointestinal cells are not regenerating as quickly and are less sensitive.
    • Nerve and muscle cells are the slowest to regenerate and are the least sensitive cells.

    Repair Damage

    • Cells have a tremendous ability to repair damage.
    • Not all radiation effects are irreversible.
    • In many instances, cells are able to completely repair any damage and function normally.

    Organ Sensitivity

    • The sensitivity of organs to radiation correlates with the relative sensitivity of the cells from which they are composed.
    • The order of organ sensitivity from most sensitive to least sensitive is:
      • Blood-forming organs
      • Reproductive and gastrointestinal tract organs
      • Skin
      • Muscle and brain

    Radiation Effects

    • Biological effects of radiation are typically divided into two categories:
      • High doses (acute) over short periods of time, producing short-term effects.
      • Low doses (chronic) over an extended period of time, producing long-term effects.

    High Dose Effects

    • High doses can kill cells, leading to tissue and organ damage.
    • Acute radiation syndrome (ARS) can occur, causing a rapid whole-body response.
    • Effects of high doses include:
      • Blood count changes
      • Vomiting
      • Death
      • Skin burns
      • Hair loss
      • Sterility
      • Cataracts

    Low Dose Effects

    • Low doses can damage or change cells, leading to genetic, somatic, or in-utero effects.
    • Categories of effects of exposure to low doses of radiation include:
      • Genetic: effects suffered by the offspring of the individual exposed.
      • Somatic: effects primarily suffered by the individual exposed, including cancer.
      • In-utero: effects suffered by a developing embryo/fetus, seen after birth.

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