Cellular response to radiation

Question 1

What are the three cellular responses to radiation

Answer 1

1. Division delay
2. Interphase death
3. Reproductive failure

Question 2

What is the Mitotic index

Answer 2

is the percentage of cells undergoing mitosis, it is used to measure the effects of various types of cellular responses to radiation, including division delay, reproductive failure, and interphase death

Question 3

Mitotic index formula

Answer 3

Number of cells in mitosis at any time/ total number of cells in the population

Question 4

What is division delay

Answer 4

when the cells do not divide as they are supposed to
- When irradiated cells are undergoing mitosis
- Delay for cells about to undergo mitosis
- If a dose is low cells can recover from the delay.
- the mitotic index decreases (the cells delay mitosis to repair DNA damage)

Question 5

Division delay is dose-dependent what does this mean

Answer 5

the extent to which the mitotic index (percentage of dividing cells) decreases and the duration of the division delay both depend on the radiation dose. Higher doses of radiation typically cause a more significant reduction in the number of cells entering mitosis and result in a longer delay before cell division can resume. Essentially, the greater the radiation dose, the stronger the impact on cell division.

Question 6

What is interphase death (apoptosis)

Answer 6

Apoptosis is programmed cell death, however, it can be radiation-induced as it occurs when ionizing radiation causes significant damage to a cell’s DNA, triggering programmed cell death, however it does not occur immediately after irradiation

Question 7

Can apoptosis occurs in non dividing cells or rapidly dividing cells

Answer 7

This can occur in both non-dividing cells and rapidly dividing cells

Apoptosis is insufficient in cancer resulting in uncontrolled cell proliferation

Question 8

What is reproductive failure

Answer 8

the % of cells surviving after irradiation that are capable of reproduction, If reproductive ability of cell is terminated it prevents the transmission of damage to future generations however the cell itself is still alive and can metabolise.

Question 9

Which of the three usually results from chronic exposure

Answer 9

repeated radiation exposure from fluoroscopic procedures, reproductive failure is often highlighted as a key factor because it directly affects the ability of skin cells to regenerate and repair, leading to chronic damage.

Question 10

Which of the three usually results from acute exposure

Answer 10

interphase death would be the immediate effects of high doses of radiation on rapidly dividing cells, such as those in the bone marrow or intestinal lining. For instance, exposure to a high dose of radiation can cause many of these cells to die before they can enter mitosis, leading to acute conditions like anemia or gastrointestinal distress due to the loss of functional cells in these critical tissues.

and

division delay is the delayed healing of wounds or skin lesions. After radiation exposure, if skin cells experience division delay, they may not regenerate quickly enough to repair damage, leading to prolonged erythema and an increased risk of infection or ulceration. In the gastrointestinal tract, division delay can result in symptoms like nausea and diarrhea due to insufficient renewal of intestinal lining cells.