Principles of Toxicology

These flashcards cover key vocabulary terms related to the principles of toxicology, specifically focusing on absorption, distribution, metabolism, and excretion of toxicants.

Absorption

The process by which substances cross body membranes to enter systemic circulation.

Volume of Distribution

A pharmacological term that describes how a toxicant distributes throughout the body after entering the bloodstream.

Biotransformation

The chemical modification made by an organism on a chemical compound, enhancing elimination and often increasing water solubility.

First-pass metabolism

The metabolism of a substance before it reaches systemic circulation, often reducing its effectiveness.

Active Transport

An energy-dependent process that moves toxicants against their concentration gradient through cell membranes.

Facilitated Transport

A process where molecules move across membranes via specific transport proteins without expenditure of energy.

Xenobiotic Transporters

Proteins that facilitate the transport of xenobiotic compounds in and out of cells.

Bioavailability

The fraction of an administered drug or toxicant that reaches systemic circulation.

Enterohepatic Recirculation

A process where substances are reabsorbed into circulation after being excreted into the intestines, potentially prolonging toxicity.

Phase I Reactions

Metabolic reactions that introduce or expose polar functional groups on xenobiotics, facilitating further metabolism.

Phase II Reactions

Conjugation reactions that increase the water solubility of metabolites, making them easier to excrete.

Lipid Solubility

The property of a substance that determines its ability to cross lipid membranes, influencing absorption and distribution.

Ionization State

The ratio of ionized to non-ionized forms of a compound, which affects its permeability across cell membranes.

Glomerular Filtration

The process by which the kidneys filter blood, allowing for the excretion of polar and ionized compounds.

Pulmonary Absorption

The absorption of gases, vapors, or particles through the lungs into the bloodstream.

Dermal Absorption

The process by which substances are absorbed through the skin.

Tissue Affinity

The tendency of a chemical to accumulate within specific tissues, impacting its toxicity and effectiveness.

Storage Depot

Tissues where a toxicant may accumulate but may not lead to immediate toxicity.

Elimination

The process of removing toxicants from the body through various routes, primarily via urine and feces.

pKa

The pH at which a compound exists in equal concentrations of ionized and non-ionized forms, influencing its absorption properties.