Radiation Effects On The Cell And Organisms Flashcards
On which cells X-irridation have the strongest effect
The highest reproductive activity
The longest mitosis phase
The lowest morphological and functional differentiation
Cell radio sensitivity is directly proportional to
Rate of cell division
Inversely proportional to the degree of cell differentiation
Which cell types are most at risk from radiation
Actively dividing cells
Nor fully mature cells
Highly sensitive cells to radiation
Germ cells
Immature RBCs
Lymphocytes
Moderately highly radiosensitive cells
Epithelial cells
Low radiosensitivity cells
Muscle
Nerve
In which step of cell cycle cells are most sensitive to cell killing?
Shortly before M phase
Late interphase( G2) and during M phase
In which step of cell cycle higher resistance to radiation is observed
S phase
Late G1 phase
G0 phase
Genetic radiation effects
Chromatid and chromosome breaks
Alteration of bases : localized changes of genetic information
Most of these mutations are RECESSIVE
Relation between mutation rate and dose,dose rate
Mutation rate:
Linear increase with dose
Independent of dose rate
Chromosome breaks are
Dose rate dependent
More pronounced at high LET radiation
Cells are more likely to show them if irritated in G1 phase
When 1 breakage occurs
When radiation comes after the S phase
When 2 breakage occurs
When radiation comes in G1 phase
What are the two consequences of survival curve
There is no radiation threshold for lethality
The dose required to irradicate the whole population increases with the size of the irradiated population
What shoulder region indicate
Cells conduct repair of damage and are capable of surviving
