chapter 35 flash cards

Vocabulary practice flashcards covering deterministic effects of radiation, acute radiation syndromes, tissue damage, cytogenetic effects, and chromosome aberrations.

Deterministic Effects

Radiation responses that increase in severity with increasing dose above a threshold dose, occurring due to an increased number of damaged cells after large radiation doses.

Acute Radiation Syndrome (ARS)

The sequence of events that follows high-level radiation exposure and leads to death within days or weeks.

Hematologic Syndrome

An acute radiation syndrome occurring at doses of approximately $2\,Gy_t$ to $10\,Gy_t$, characterized by severe depression of blood cell counts leading to anemia, hemorrhage, and infection.

Gastrointestinal (GI) Syndrome

An acute radiation syndrome occurring at doses of approximately $10\,Gy_t$ to $50\,Gy_t$, caused by damage to the lining of the small intestine, leading to desquamation, severe dehydration, and electrolyte imbalance.

Central Nervous System (CNS) Syndrome

An acute radiation syndrome occurring at doses in excess of approximately $50\,Gy_t$, caused by brain edema and increased intracranial pressure leading to coma and death.

Prodromal Stage

The immediate response stage following total-body radiation doses above $1\,Gy$, characterized by symptoms such as nausea, vomiting, diarrhea, and leukopenia lasting from hours to days.

Latent Stage

The period of apparent well-being following the prodromal stage during which signs and symptoms of radiation sickness temporarily subside.

Manifest Illness Stage

The stage of acute radiation syndrome where symptoms characteristic of the specific subsyndrome return in force, lasting from several hours to about two months before death or recovery.

LD 50/60

The whole-body radiation dose that causes $50\%$ of irradiated subjects to die within $60\text{ days}$, which is approximately $3.5\,Gy$ for humans without medical support.

Mean Survival Time (MST)

The average time between an acute lethal radiation dose and death, which generally decreases as whole-body dose increases.

Atrophy

The shrinkage of an organ or tissue caused by cell death.

Erythema

A sunburn-like reddening of the skin resulting from radiation exposure.

Desquamation

Ulceration and denudation of the skin following severe radiation injury.

Mature Follicle Oocyte

The most radiosensitive cell stage during female germ cell development.

Gametogenesis Progression

The maturation pipeline of male and female germ cells starting from stem cells (spermatogonia, oogonia) to mature gametes (sperm, ovum).

Cytogenetics

The study of the genetics of cells, particularly cell chromosomes.

Microscopic Cytogenetic Aberrations

Visible structural chromosome abnormalities produced by radiation damage, including isochromatids, dicentrics, and ring chromosomes.

Karyotype

A chromosome map showing the $22\text{ pairs}$ of autosomes and one pair of sex chromosomes ($X$ and $Y$).

Chromosome S Phase Replication

The biological phase in which a single-chromatid chromosome replicates into a double-chromatid structure joined at the centromere.

Single-Hit Chromosome Aberration

Radiation damage caused by a single hit to a chromosome in $G_1$ or $G_2$ phase, which follows a linear, nonthreshold dose-response relationship.

Multi-Hit Chromosome Aberration

Severe structural alterations resulting from multiple hits to chromosomes in $G_1$ or $G_2$ phase, forming ring or dicentric chromosomes and following a nonlinear, nonthreshold relationship.

Aberration Kinetics Curve

Dose-response comparison illustrating that single-hit aberrations increase linearly with radiation dose, while multi-hit aberrations increase nonlinearly and predominate above $1\,Gy$.

Reciprocal Translocations

Multi-hit chromosome aberrations involving gene rearrangement without loss of genetic material, requiring karyotypic analysis for detection.