Toxicology Flashcards
studies the cellular and biochemical effects of toxins
Mechanistic toxicology
provide insights to therapeutics and
improved laboratory tests that would assess the degree of exposure of poisoned
individuals
Mechanistic toxicology
studies animal exposure to poisons and use the findings to interpret what would be the level that would be considered lethal for humans
Descriptive toxicology
important in risk assessment, which would be
establishing the standards that describe the level of exposure of certain substances that will be a public health or safety risk.
Descriptive toxicology
medicolegal consequences of toxin
exposure
Forensic toxicology
special focus on the validation of analytic methods to ascertain the cause of death
Forensic toxicology
involves studying interrelationships between toxin exposure and disease states
Clinical toxicology
includes diagnostic testing and therapeutic
interventions
Clinical toxicology
gathers and evaluates the data derived from mechanistic and descriptive studies to determine standards that define the level of exposure that is not considered harmful to public health or safety
Regulatory toxicology
identification of toxic substances through
laboratory analysis of body fluids, wastes or tissues.
Analytical toxicology
involves the study of substances that contaminate food, water, soil, or the atmosphere.
Environmental toxicology
responsible for the delivery of safe and edible food supply to consumers.
Food toxicology
studies the health effects from exposure to toxic substances in the workplace.
Occupational toxicology
Actual amount of chemical that enters the body.
dose
dose was given over a short period of time usually within 24 hours
acute exposure
dose was given over a long period of time
chronic exposure
Contact with a chemical that can occur one time or occur on a short-term or long-term basis
Exposure
describes the relationship between exposure and health effect, often determined by measuring the effect relative to the dose.
Dose-
response
Exogenous agents causing adverse effects on biological systems and are often used to describe chemicals derived from animals,
plants, minerals, or gas
Poisons
effect of a chemical exposure that will produce injury to one kind of living organism but has no effect to another closely related living organism.
Selective
toxicity
dose or exposure level below which the harmful effects of the chemical are not seen in a population.
Threshold
dose
Threshold
dose also known as
no observed adverse effect level (NOAEL) or the no effect level (NEL)
Threshold
dose is not applicable to
cancer-causing
substances
fatal effects of toxins to the body after exposure through the different routes with a chemical.
Toxic
is any chemical that can injure or kill humans, animals, or plants; used when talking about toxic substances that are produced by or are a by-product of human-made activities.
Toxicant
Endogenous substances that are produced naturally in living organisms.
Toxins
The degree to which a chemical substance damages an organ system, disrupts a biochemical process or disturbs an enzyme
system
Toxicity
The amount it takes to elicit a toxic effect compared with other chemicals
Potency
This is done for some toxic exposures, such as blood lead levels or metabolites of chemicals
Biologic
monitoring
4 routes of exposure
inhalation
injection
ingestion
skin (transdermal absorption)
fastest route for toxins to enter the systemic circulation
inhalation
damage by inhalation is determined by
concentration
size of molecule
solubility in blood
respiratory rate
respiratory tract condition
length of exposure
route most often seen in clinical settings
ingestion
absorption of toxin in GI tract depends on
concentration in target organ
chemical and physical form
distribution
metabolism
length of time in target tissue
can also introduce toxic susbtances to the blood
injections
examples of injection methods
intravenous
intramuscular
subcutaneous
another term for skin route of exposure
transdermal absorption
skin is more permeable to
fat-soluble chemicals
any exposure less than 24 hours up to 72
hours
acute exposure
require less than 24 hours for toxicity
Toxic gases
describes repeated exposures to a substance for greater than 72 hours but less than 1 month.
Subacute
continuous or repeated intermittent
exposure
chronic exposure
period extending beyond 3
months, between acute and chronic
sub chronic exposure
Most adverse drug reactions and most complications are usually
associated with
continuous or intermittent repeated
defined as the
cumulative action of its absorption, biotransformation and elimination.
disposition
factors that could affect chemical
disposition
biochemical nature of the toxicant
exposure route
exposure dose
site of action
the disposition is dependent on the processes of
absorption
biotransformation
elimination
the process by which toxicants cross body membranes and enter the bloodstream.
Absorption
main sites of absorption
GI tract
lungs
skin
most common cause
of unintentional exposure to a toxicant
Accidental ingestion
intentional overdoses most
frequently occur via
oral route
If a toxicant is an organic acid or base, this tends to be absorbed by __, existing in its most ____
simple diffusion
lipid soluble form
The amount of chemical that could enter the
systemic circulation after oral administration
depends on the
amount absorbed into the GI cells, biotransformation by the GI cells
extraction by the liver into the bile
phenomenon of the removal of chemicals in the liver before entrance into the systemic circulation.
first- pass effect
a certain chemical with high first- pass effect, then this will have _____ absorption
lower
absorption of the toxicant depends on
solubility
dissolution rate
pH
presence of food, digestive enzymes, bile acids, bacterial microflora
motility and permeability of the GI tract.
acts as a primary barrier in absorption of inhaled gases
nose
a film of fluid retains gas molecules if they:
are very water soluble
react with cell surface components
the smaller the particle, the _______ into the
respiratory tree the particle will deposit.
further
Soluble particles may dissolve in the
mucus
Particles that are ____ and smaller penetrate the alveolar sacs of the lungs.
1μm
have the greatest likelihood of depositing in the alveolar region
Nanoparticles
The overall removal of particles from the alveoli is relatively efficient. T/F
F
outermost layer, is the single most important barrier to preventing
absorption of xenobiotics into the body.
stratum corneum
important factors of stratum corneum
thickness
integrity
hydration status
generally absorbed quickly
Lipophilic (lipid-loving) compounds
the movement of
compounds through the layers of the skin
passive diffusion
Absorption is indirectly proportional to the
molecular size
introduces the toxicant directly into the bloodstream, which
surpasses the process of absorption
Intravenous route
results in rapid absorption because of the rich blood supply and the relatively large surface area of the peritoneal cavity
Intraperitoneal injection
absorbed at slower rates but
eventually enter the systemic circulation
Subcutaneous and intramuscular injections
primary factors that could influence distribution into the cells of a
particular organ or tissue
Blood flow
rate of diffusion out of the capillary bed
When the toxicants are concentrated in a specific tissue which may or may not be their site of toxic action, the area is described as a
storage depot
5 storage depots in the body
plasma
liver
kidney
fat
bone
major protein in plasma that binds many different compounds as
compared to other proteins.
albumin
Because of their high molecular weight, plasma
protein-bound toxicants cannot easily cross capillary walls. T/F
T
In plasma, Toxicity is typically manifested by the amount of xenobiotic that is
unbound
high binding capacity to plasma proteins
low toxicity
could compete for endogenous substances that are bound to albumin
xenobiotics
have high capacity for binding a range of chemicals, either toxicant or therapeutic drugs.
liver and kidney
has a rich supply of blood and thus may attain high initial concentration of a xenobiotic.
liver
protective in some way since this storage depot enables the toxicant to not be
stored in the target organ.
body fat storage depot
obesity causes ______ toxicity for lipophilic toxicants
less severe
fat is rapidly mobilized causes
sudden increase in concentration of chemical
Xenobiotics are deposited into bones as a result of the exchange taking place
between the bone surface and the
ECF
for a toxicant to be excreted through the urine, it has to undergo
biotransformation.
process of converting fat- soluble chemicals (which are readily absorbed from the GI tract and other sites) into water-soluble chemicals, which are readily excreted into the urine or bile.
Xenobiotic biotransformation or drug metabolism
major routes of excretion
urine
stool
mechanisms the kidney
uses to remove end products from the body
glomerular filtration
tubular excretion by passive diffusion and active tubular secretion.
important consideration in urine excretion
age - incomplete kidney dev at birth, more slowly in newborns
relatively slow process that is a major pathway of elimination only for compounds that have low rates of biotransformation and/or low renal or biliary clearance.
intetsinal excretion
Gut microflora are capable _______ but favors ______ than secretion
biotransformation
reabsorption
most important contributing source to fecal excretion
biliary route (liver > bile/ hepatic venous blood)
