Phases of Toxic Phenomenon Exposure and Absorption Quiz

Route of exposure = Determines how the toxicant enters the body Concentration of the substance at the site of contact = Affects the rate of absorption Chemical and physical properties of the substance = Influences how easily the substance is absorbed External dose vs. internal dose = Fraction absorbed for skin, oral, and respiratory exposure

Gastrointestinal tract = Important for environmental exposure to contaminants from food and water Respiratory system = Route for inhaled toxicants to enter the body Injection or implantation = Directly introduces substances into the body Skin contact = Allows for absorption of substances through the skin

Exposure phase = Toxicants enter the body by absorption Absorption phase = Toxicants cross cellular barriers to exert effects on internal organs Local toxicity phase = May occur before a substance is fully absorbed Variability phase = Absorption varies based on chemical properties and exposure route

<p>Respiratory tract = Important for environmental and occupational exposure to air contaminants Skin = Important environmental and occupational exposure route Cell Membranes = Surround all body cells and consist of a phospholipid bilayer Passive transfer = Most common way that xenobiotics cross cell membranes</p> Signup and view all the answers

<p>Facilitated diffusion = Assisting in the movement of substances across cell membranes without cellular energy Active transport = Requiring cellular energy to move substances across cell membranes Endocytosis = Involving engulfing of substances by the cell membrane Passive Transfer = Simple diffusion or osmotic filtration without cellular energy requirements</p> Signup and view all the answers

<p>Lipid solubility = Determines how readily a substance can diffuse through the phospholipid membrane Molecular size = Affects whether a substance can pass through small pores in the membrane or the lipophilic interior Degree of ionization = Influences a chemical substance's ability to move through a membrane Aqueous pores = Allow small water-soluble molecules to pass through cell membranes</p> Signup and view all the answers

<p>Nasal or oral aerosol inhalers = Respiratory tract exposure route Consumer and pharmaceutical products applied directly to the skin = Skin exposure route Styling web pages = CSS usage Database queries = SQL usage</p> Signup and view all the answers

<p>Hydrophilic = Phosphate head of a phospholipid molecule attracted to water Lipophilic = Lipid tail of a phospholipid molecule attracted to lipid-soluble substances Polar = Having an uneven distribution of charge, attracting water Facilitated transport = Specialized mechanisms aiding substances in crossing cell membranes</p> Signup and view all the answers

<p>Facilitated Diffusion = Carrier-mediated transport mechanism that does not require energy Active Transport = Movement against the concentration gradient requiring cellular energy Endocytosis = Process where the cell engulfs substances with a section of its wall Distribution = Absorbed toxicants entering the blood supply for transport</p> Signup and view all the answers

<p>Phagocytosis = Engulfing of large particles suspended in extracellular fluid Pinocytosis = Engulfing of liquids or very small particles in suspension Facilitated Diffusion = Carrier-mediated transport mechanism that does not require energy Active Transport = Movement against the concentration gradient requiring cellular energy</p> Signup and view all the answers

<p>Xenobiotics = Transported into the liver, kidney, and central nervous system Sugar and amino acids = Transported into RBCs and the CNS Sodium and potassium = Moved against concentration gradient with the help of ATP pump Toxicants absorbed through skin = Enter peripheral blood supply for distribution to distant tissues</p> Signup and view all the answers

<p>Lung phagocytes = Important for phagocytosis process Liver and spleen cells = May engulf large particles suspended in extracellular fluid White blood cells (lymphocytes) = Involved in circulating lymph within the lymphatic system Red blood cells (RBCs) = Transport sugar and amino acids into them</p> Signup and view all the answers

<p>Lymphatic system = Drains excess fluid from tissues and transports toxicants to other regions of the body Pulmonary circulation = Transports oxygenated blood and toxicants from lungs to heart Systemic circulatory pathway = Distributes toxicants to tissues throughout the body Skin absorption route = Allows toxicants to enter peripheral blood supply for distribution</p> Signup and view all the answers

<p>Physical and chemical properties of the toxicant = Determines likelihood of distribution to tissues Concentration of the toxicant in the blood and in the tissues = Creates concentration gradient for distribution Volume of blood flowing through a specific tissue = Affects rate of distribution to organs or tissues Presence of special 'barriers' to slow down toxicant entrance = Delays toxicant entrance into tissues</p> Signup and view all the answers

<p>Intracellular water = One of the main compartments where water is partitioned Extracellular water (interstitial water and plasma water) = Another main compartment where water is partitioned Plasma compartment = Compartment where a chemical with high plasma concentration distributes only Both compartments (intracellular and extracellular) = Compartment where a chemical with low plasma concentration distributes throughout</p> Signup and view all the answers

<p>Storage = May lower the concentration of the toxicant Biotransformation = One of the processes that affects toxicokinetics Elimination = Another process that affects toxicokinetics Diffusion out of the capillary bed into cells = Determines rate of distribution to organs or tissues</p> Signup and view all the answers

<p>Plasma protein = Major protein in plasma that binds many different compounds Liver and kidney = Organs serving as storage depots for toxicants Adipose tissue = Another storage depot for toxicants in the body Bone = Part of the body that serves as a storage depot for some toxicants</p> Signup and view all the answers

<p>Protein-ligand interactions = Primarily occur due to hydrophobic forces, hydrogen bonding, and van der Waals forces Reversibility of interactions = Property of interactions between plasma proteins and toxicants Plasma proteins crossing capillary walls = Cannot occur due to high molecular weight of proteins and bound toxicants Degree of plasma protein binding and toxicity = Compound with high binding may show less toxicity than less extensively bound ones</p> Signup and view all the answers

<p>Fat = Lowers the concentration of the toxicant in the target organ Bone = Dynamic deposition and reversible storage of toxicants Muscle = Highly lipophilic toxicants are distributed and concentrated Liver = Concentrates a multitude of chemicals</p> Signup and view all the answers

<p>Liver = High capacity for binding a multitude of chemicals Kidney = High capacity for binding a multitude of chemicals Brain = Restricts access to toxicants through tight capillary endothelial cells Skin = Does not play a significant role in chemical binding</p> Signup and view all the answers

<p>Blood-Brain Barrier = Prevents diffusion of polar compounds through paracellular pathways Placental Barrier = Slows down the diffusion of toxicants from maternal to fetal circulation Skin Barrier = Serves to limit the diffusion of water-soluble toxicants Lung Barrier = Allows easy diffusion of toxicants into the bloodstream</p> Signup and view all the answers

<p>CNS Interstitial Fluid = Limits movement of water-insoluble compounds by paracellular transport Blood Plasma = Facilitates diffusion of water-insoluble compounds into tissues Lymphatic Fluid = Contains high protein concentration for paracellular transport Urine = Excretes water-soluble toxicants efficiently</p> Signup and view all the answers

<p>Blood-Brain Barrier = Restricts entry of toxicants into the central nervous system Placental Barrier = Reduces exposure of fetal tissues to maternal toxicants Skin Barrier = Allows easy penetration of chemical substances Intestinal Barrier = Absorbs and distributes toxicants throughout the body</p> Signup and view all the answers