RADIATION BIOLOGY EXAM SCRIPT 2026/2027
QUESTIONS AND SOLUTIONS RATED A+
✔✔What effect may be observed after irradiation of blood vessels? - ✔✔Occlusion of
small vessels can lead to loss of nutrients and oxygen.
✔✔What are the results of high doses of radiation delivered to the heart? -
✔✔Pericarditis and pancarditis.
✔✔What does a moderate dose of radiation produce in growing bone and cartilage? -
✔✔Temporary delay of mitosis and death of immature cells.
✔✔What does a high dose of radiation produce in growing bone and cartilage? -
✔✔May result in no more bone formation.
✔✔Why is the liver considered a moderately radiosensitive organ? - ✔✔Due to large
blood supply.
✔✔What changes may be observed after irradiation of the urinary system? - ✔✔Loss of
tubules, kidney becomes atrophic, renal failure.
✔✔Why is the CNS considered the most radioresistant system in adults? - ✔✔High
doses cause myelitis, necrosis, fibrosis due to vascular changes.
✔✔What happens as the radiation dose is increased? - ✔✔Life span is decreased.
✔✔Define LD50/30 and LD50/60. - ✔✔50/30 = lethal dose, 50% population dies in 30
days; 50/60 = lethal dose, 50% population dies in 60 days.
✔✔Where does the data on radiation exposure to humans come from? - ✔✔Atomic
bomb, medical exposure, occupational exposure, Chernobyl, fallout experiments.
✔✔What characterizes the prodromal stage of radiation syndrome? - ✔✔Characterized
by nausea, vomiting, diarrhea.
✔✔What characterizes the latent stage of radiation syndrome? - ✔✔Individual feels
well, but changes are occurring.
✔✔What characterizes the manifest illness stage of radiation syndrome? - ✔✔Shows
signs and symptoms reflecting the damaged organ system.
✔✔What is manifest illness? - ✔✔The individual feels well but changes are occurring.
, ✔✔What are the signs of radiation syndrome in mammals? - ✔✔Signs and symptoms
reflect the damaged organ system.
✔✔What is the dose range for CNS syndrome? - ✔✔20-50 Gy.
✔✔What symptom occurs during the prodromal stage of GI syndrome? - ✔✔Cramping.
✔✔What is the dose range for bone marrow syndrome? - ✔✔1-6 Gy.
✔✔What symptom occurs during manifest illness of GI syndrome? - ✔✔Fever.
✔✔What is the dose range for both bone marrow and GI syndrome? - ✔✔6-10 Gy.
✔✔What are the prodromal stage symptoms of CNS syndrome? - ✔✔Extreme
nervousness, confusion, severe nausea and vomiting, loss of consciousness, and
burning sensations to skin.
✔✔What symptoms occur during manifest illness of CNS syndrome? - ✔✔Diarrhea,
convulsions, and coma.
✔✔What causes death in bone marrow syndrome? - ✔✔Anemia, hemorrhage, or
infection.
✔✔What causes death in GI syndrome? - ✔✔Dehydration, decreased absorption, and
infection.
✔✔What causes death in CNS syndrome? - ✔✔Increased pressure from blood vessel
damage and tissue inflammation.
✔✔What are the three general changes observed in an embryo or fetus after
irradiation? - ✔✔Lethality, congenital abnormalities, long-term late effects.
✔✔What effects can be produced from mutation of sperm or ovum? - ✔✔Genetic
effects.
✔✔What effects can be produced from direct exposure to the fetus? - ✔✔Congenital
effects.
✔✔What is the time frame for major organogenesis? - ✔✔From the 10th day post-
conception to the 6th week.
✔✔What characterizes the fetal stage? - ✔✔A period of growth.
QUESTIONS AND SOLUTIONS RATED A+
✔✔What effect may be observed after irradiation of blood vessels? - ✔✔Occlusion of
small vessels can lead to loss of nutrients and oxygen.
✔✔What are the results of high doses of radiation delivered to the heart? -
✔✔Pericarditis and pancarditis.
✔✔What does a moderate dose of radiation produce in growing bone and cartilage? -
✔✔Temporary delay of mitosis and death of immature cells.
✔✔What does a high dose of radiation produce in growing bone and cartilage? -
✔✔May result in no more bone formation.
✔✔Why is the liver considered a moderately radiosensitive organ? - ✔✔Due to large
blood supply.
✔✔What changes may be observed after irradiation of the urinary system? - ✔✔Loss of
tubules, kidney becomes atrophic, renal failure.
✔✔Why is the CNS considered the most radioresistant system in adults? - ✔✔High
doses cause myelitis, necrosis, fibrosis due to vascular changes.
✔✔What happens as the radiation dose is increased? - ✔✔Life span is decreased.
✔✔Define LD50/30 and LD50/60. - ✔✔50/30 = lethal dose, 50% population dies in 30
days; 50/60 = lethal dose, 50% population dies in 60 days.
✔✔Where does the data on radiation exposure to humans come from? - ✔✔Atomic
bomb, medical exposure, occupational exposure, Chernobyl, fallout experiments.
✔✔What characterizes the prodromal stage of radiation syndrome? - ✔✔Characterized
by nausea, vomiting, diarrhea.
✔✔What characterizes the latent stage of radiation syndrome? - ✔✔Individual feels
well, but changes are occurring.
✔✔What characterizes the manifest illness stage of radiation syndrome? - ✔✔Shows
signs and symptoms reflecting the damaged organ system.
✔✔What is manifest illness? - ✔✔The individual feels well but changes are occurring.
, ✔✔What are the signs of radiation syndrome in mammals? - ✔✔Signs and symptoms
reflect the damaged organ system.
✔✔What is the dose range for CNS syndrome? - ✔✔20-50 Gy.
✔✔What symptom occurs during the prodromal stage of GI syndrome? - ✔✔Cramping.
✔✔What is the dose range for bone marrow syndrome? - ✔✔1-6 Gy.
✔✔What symptom occurs during manifest illness of GI syndrome? - ✔✔Fever.
✔✔What is the dose range for both bone marrow and GI syndrome? - ✔✔6-10 Gy.
✔✔What are the prodromal stage symptoms of CNS syndrome? - ✔✔Extreme
nervousness, confusion, severe nausea and vomiting, loss of consciousness, and
burning sensations to skin.
✔✔What symptoms occur during manifest illness of CNS syndrome? - ✔✔Diarrhea,
convulsions, and coma.
✔✔What causes death in bone marrow syndrome? - ✔✔Anemia, hemorrhage, or
infection.
✔✔What causes death in GI syndrome? - ✔✔Dehydration, decreased absorption, and
infection.
✔✔What causes death in CNS syndrome? - ✔✔Increased pressure from blood vessel
damage and tissue inflammation.
✔✔What are the three general changes observed in an embryo or fetus after
irradiation? - ✔✔Lethality, congenital abnormalities, long-term late effects.
✔✔What effects can be produced from mutation of sperm or ovum? - ✔✔Genetic
effects.
✔✔What effects can be produced from direct exposure to the fetus? - ✔✔Congenital
effects.
✔✔What is the time frame for major organogenesis? - ✔✔From the 10th day post-
conception to the 6th week.
✔✔What characterizes the fetal stage? - ✔✔A period of growth.
