Chapter 5 Flashcards
(50 cards)
Which of the following statements regarding the biological effect mechanisms of the direct theory is false?
A) Most dental x-ray photons pass through the cell, causing no damage.
B) X-ray photons may collide with important cell chemicals and break them apart.
C) Ionization can cause critical damage to large molecules.
D) Irradiated cells cannot be repaired.
D) Irradiated cells cannot be repaired.
They can be repaired
Which of the following statements regarding the biological effect mechanisms of the indirect effect is false?
A) Ionization dissociates water into hydrogen and hydroxyl radicals.
B) Ions have a strong tendency to seek out new combinations.
C) New chemicals, such as hydrogen peroxide, can form from hydrogen and hydroxyl radicals.
D) Radiation must be massive to destroy entire body tissues that result in death.
B) Ions have a strong tendency to seek out new combinations.
Indirect effect is interaction of radiation with water molecules
Which of the following is most sensitive to damage from radiation?
A) Bone cells
B) Epithelial cells
C) Lymphocytes
D) Muscle cells
C) Lymphocytes
Which of the following statements about radiation repair is false?
A) Somatic cells cannot repair radiation damage.
B) Scientists believe that some radiation effects are cumulative.
C) Ions have a strong tendency to recombine immediately to form water again.
D) The quantity, duration, and body area irradiated determine the amount of damage inflicted by the radiation.
A) Somatic cells cannot repair radiation damage.
Somatic cells can repair radiation damage
Which of the following statements regarding the theory established by a threshold dose-response curve is true?
A) There is a dose below which no biological response would be expected.
B) It predicts the effects of very low levels of radiation exposure.
C) It indicates that any amount of radiation has the potential to cause a biological response.
D) It has been adopted by the radiation protection community as the conservative approach to radiation exposure.
A) There is a dose below which no biological response would be expected.
Each of the following is a potential effect of a low dose of radiation except one. Which one is the exception?
A) No cell response
B) Cell repairs itself and functions at preexposure levels
C) Cell repairs itself abnormally
D) Cell becomes radioactive
D) Cell becomes radioactive
Which of the following statements regarding radiation injury is false?
A) The smaller the area of tissue exposure, the greater damage to the individual.
B) The greater the dose, the more severe the probable biological event.
C) The rate at which the radiation is absorbed may determine which biological effects occur.
D) A given dose may produce fewer biological effects if the cells have a chance to recover.
A) The smaller the area of tissue exposure, the greater damage to the individual.
Which of the following statements regarding radiation injury is false?
A) The amount of injury to an individual depends on the volume of tissue radiated.
B) The lethal dose (LD 50/30) for humans is 1.5 grays.
C) Younger, more rapidly dividing cells are more likely to incur damage.
D) Individuals vary in radiation sensitivity within the same species.
B) The lethal dose (LD 50/30) for humans is 1.5 grays.
(The LD 50/30 for humans is 4.5 grays, not 1.5 grays.)
The lethal dose (LD 50/30) of radiation for humans is estimated to be:
A) 4,500 grays
B) 450 grays
C) 45 grays
D) 4.5 grays
D) 4.5 grays
Which of these is not a symptom of acute radiation syndrome?
A) Constipation
B) Nausea
C) Hemorrhage
D) Hair loss
A) Constipation
Which of the following is not a component of factors determining radiation injury?
A) Actively dividing cells with high mitotic activity are less sensitive.
B) Immature cells are more sensitive.
C) More specialized cells are more radioresistant.
D) Cells are most susceptible to injury during cell division.
A) Actively dividing cells with high mitotic activity are less sensitive.
Which of the following groups of cells are correctly ranked in order of radiosensitivity beginning with the most sensitive?
A) Muscle, brain, red blood, white blood
B) Reproductive, bone, nerve, muscle
C) Brain, bone, connective tissue, white blood
D) Red blood, bone, muscle, epithelial
B) Reproductive, bone, nerve, muscle
Continued exposure to radiation over prolonged periods may result in each of the following except one. Which one is the exception?
A) May alter the ability of genetic cells to reproduce normally.
B) May affect the ability of genetic cells to repair damage.
C) May produce offspring with increased resistance to radiation exposure.
D) May result in cumulative chromosome damage.
C) May produce offspring with increased resistance to radiation exposure.
What is the approximate surface (skin) dose of radiation from a full mouth series?
A) 12.6 mSv
B) 8 mSv
C) 0.4 mSv
D) 0.0005 mSv
A) 12.6 mSv
Which of these periods immediately follows radiation exposure?
A) The period of injury
B) The latent period
C) The reparable damage period
D) The recovery period
B) The latent period
When the severity of change is dependent on the radiation dose, the effect is called a(n):
A) stochastic effect
B) deterministic effect
C) acute radiation effect
D) lethal dose effect
B) deterministic effect
At what dose of whole-body radiation would an observable short-term effect of acute radiation syndrome result?
A) 0.01 Gy
B) 0.25 Gy
C) 1.0 Gy
D) 1.5 Gy
D) 1.5 Gy
Tissues have the capacity to repair radiation damage to a certain degree. However, some damage cannot be repaired and tissues remain weakened, especially with repeated exposures. This is called:
A) a long-term effect
B) radioresistant tissue
C) a cumulative effect
D) a stochastic effect
C) a cumulative effect
What theory of radiation damage to cells results from free radicals combining to form toxins such as hydrogen peroxide?
A) Primary
B) Secondary
C) Indirect
D) Direct
C) Indirect
A threshold dose-response relationship indicates that any dose, regardless of amount, can be expected to produce a biological response. A linear dose-response relationship indicates that the biological response is directly proportional to the dose.
A) The first statement is true. The second statement is false.
B) The first statement is false. The second statement is true.
C) Both statements are true.
D) Both statements are false.
B) The first statement is false. The second statement is true.
Scientists do not know whether low levels of radiation exposure carry health risks.
True
A less specialized cell is more radioresistant.
False
A nonthreshold dose-response curve indicates that there is a certain level of radiation below which no biological response should be anticipated.
False
The ALARA concept means “as low as reasonably achievable.”
True