INTRO TO TOXICOLOGY Flashcards
study of how toxicants cause adverse effects on living organisms.
toxicology
science dealing with property, action toxicity, fatal dose, detection, estimation of poisions, interpretation of the result of toxocological analysis
toxicology
chemical capable of producing a harmful reaction in a living organism.
toxicant (poison)
Any change that interferes with an organism’s normal functioning.
adverse effect
damage or kill living organisms because they react with cellular components to disrupt metabolic functions
toxins
was a scientist and physician who was born in Switzerland in 1493
Paracelsus
pioneered the use of chemicals and minerals in medicine. He is sometimes called the “father” of toxicology.
paracelsus
Prenatal alcohol abuse
fetal alcohol syndrom
mercury in fish
brain damage
lead in paint
brain damage
doixon posioning
facial scarring (chloracne)
small amount of botulinum toxin
prevents wrinkle (botox)
large amount of botulinum toxin
paralysis or death
amount, usually per unit body mass, of a toxicant to which an organism is exposed
dose
measured as milligrams of toxin per kilogram of body weight = mg/kg
dose
effect on an organism resulting from exposure to a toxicant
response
dose which is expected to kill 50% of the population in the particular group.
median lethal dose (LD50)
the dose that produces a desired response in 50% of the test population when pharmacological effects are plotted against dosage.
median effective dose (ED50)
important concept pertinent to the dose–response relationship is that of _______ dose, below which there is no response
threshold
Once a living organism has been exposed to a toxin, the compound must get into the body and to its target site in an active form in order to cause an ______
adverse effect
passive and facilitated diffusion, active transport
membrane barriers
defenses of body
membrane barriers, biotransformation enzymes, elimination mechanism
ADME
absorption, distribution, metabolisim, excretion
ability of a chemical to enter the blood (blood is in equilibrium with tissues)
absorption
readily absorb gases into the blood stream via the alveoli. (Large alveolar surface, high blood flow, and proximity of blood to alveolar air)
inhalation
absorption through GI tract stomach (acids), small intestine (long contact time, large surface area–villi; bases and transporters for others)
ingestion
absorption through epidermis (stratum corneum), then dermis; site and condition of skin
dermal
the process in which a chemical agent translocates throughout the body
distribution
Blood carries the agent to and from its site of action, storage depots, organs of transformation, and organs of elimination
distribution
Rate of distribution (rapid) dependent upon ____
blood flow, characteristics of toxicant (affinity for the tissue, and the partition coefficient)
Very lipophylic compounds (DDT) will store in fat. Rapid mobilization of the fat (starvation) can rapidly increase blood concentration
Storage in Adipose tissue
Chemicals analogous to Calcium–Fluoride, Lead, Strontium
storage in bone
can displace endogenous compounds.
binding to plasma proteins
adverse effect is dependent upon the concentration of active compound at the target site for enough time
target organs
high blood flow, oxidative reactions
liver
high blood flow, concentrates chemicals
kidney
high blood flow, site of exposure
lung
oxygen dependent, irreversible damage
neurons
oxygen dependent
myocardium
rapid divide
Bone marrow, intestinal mucosa-
Adverse effects can occur at the level of the ____, ______,______, or ____
molecule, cell, organ, or organism
Molecularly, chemical can interact with
_____, ____, ____
Proteins Lipids DNA
interfere with receptor-ligand binding
chemical
interfere with membrane function
chemical
interfere with cellular energy production
chemical
bind to biomolecules
chemical
chemical can bind to perturb ______
perturb homeostasis (Ca)
Toxins are eliminated from the body by several routes
Excretion
water soluble products are filtered out of the blood by the kidney and excreted into the urine
urinary excretion
Volatile compounds are exhaled by breathing
exhalation
Compounds can be extracted by the liver and excreted into the bile. The bile drains into the small intestine and is eliminated in the feces
Biliary Excretion via Fecal Excretion
other form of excretion
milk, sweat, saliva
adverse effect depends on the concentration of active compound at the target site over time
metabolism
The process by which the administered chemical (parent compounds) are modified by the organism by enzymatic reactions.
metabolism
Biotransformation can result in the formation of reactive metabolites
bioactivation
Can drastically affect the rate of clearance of compounds
biotransformation
Can occur at any point during the compound’s journey from absorption to excretion
biotransformation
key organs in biotransformation
liver (high)
kidney, lung, intestine (medium)
others (low)
Biotransformation Pathways
phase 1 and phase 2
make the toxicant more water soluble
Phase I
Links with a soluble endogenous agent (conjugation)
Phase II
toxicology is the study of how ____ affects living organism
toxicant
also known as poison
toxicants
chemical capable of producing harmful reaction to living organism
toxicant
the ___ makes the poison
dose
example ofchemical that is good in small amount bu toxic in large amount
botulinum toxin
derived from the bacterum, Clostridium botulinum
botulinim toxin
acts to block muscular nerve signals
botulinim toxin
first biological toxin to become licensed for treatment of human disease
botulinum toxin
considered as biological weapon
botulinum toxin
may change overtime
distribution
has the highest supply of biotransformation enzymes of all organs in the body
liver
can occur at any point during the compound’s journey from absorption to excretion
biotransformation
occurs when a substance is changed from one for to another which may also change the toxic properties of substance. Usually occurs primarily on liver
biotransformation
as dose increases, percent of individuals who respond increases
dose-response relationship
known as LD50
median lethal dose
known as ED50
median effective dose
particular response needed to specify in order to define dose-response relationship
death of organism, length of time from administration of dose, consider a specific reaction from population of the same kinds of organism
