Hormesis

Definition

Hormesis is a biological phenomenon where beneficial effects result from exposure to low doses of an agent that is otherwise toxic or lethal when given at higher doses. In the context of ionizing radiation, hormesis suggests that low levels of radiation may activate repair mechanisms that protect against disease.

5 Must Know Facts For Your Next Test

1. Hormesis proposes that small doses of ionizing radiation can stimulate cellular repair mechanisms, enhancing health and longevity.
2. The concept challenges the linear no-threshold (LNT) model, which assumes any amount of radiation exposure carries risk.
3. Studies supporting hormesis show improved immune responses and reduced cancer rates in organisms exposed to low-level radiation.
4. Critics argue that the evidence for hormesis is not conclusive and call for more extensive research before revising safety standards.
5. Understanding hormesis requires knowledge of dose-response relationships and how cells react to different levels of stressors.

Review Questions

• What is the basic premise of hormesis in relation to ionizing radiation?
• How does hormesis challenge the linear no-threshold model?
• What are some observed benefits in organisms exposed to low levels of radiation according to studies on hormesis?

Related terms

Ionizing Radiation:

Radiation with enough energy to remove tightly bound electrons from atoms, creating ions. Examples include X-rays and gamma rays.

Linear No-Threshold Model (LNT): A model used in radiation protection to quantify the risk associated with exposure. It assumes any dose, no matter how small, increases cancer risk linearly without a threshold.

Dose-Response Relationship: The relationship between the amount of exposure (dose) to a substance or agent and the resulting biological effect or response.