Extra Flashcards
(26 cards)
Which of the following is NOT a clotting factor?
A) fibrinogen
B) prothrombin
C) calcium
D) femitin
E) kallikrein
D- Femitin
Fibrinogen, prothrombin, and calcium are all well-established clotting factors:
Fibrinogen is Factor I.
Prothrombin is Factor II.
Calcium is Factor IV.
Kallikrein is not a classical clotting factor but is involved in the contact activation pathway and plays a role in initiating coagulation.
METHEMOGLOBINEMIA, HEMOLYTIC ANEMIA AND RENAL DAMAGE ARE CHARACTERISTIC SYMPTOMS OF OVERDOSAGE WITH
A) Phenacetin (Acetophenin)
B) Aminopyrine
C) Aspirin
C) Colchicine
E) Allopurinol (Zyloprim)
A
Phenacetin is a known oxidizing agent that can lead to:
Methemoglobinemia: due to oxidation of hemoglobin iron from Fe²⁺ to Fe³⁺.
Hemolytic anemia: especially in individuals with G6PD deficiency.
Renal damage: particularly analgesic nephropathy, a chronic kidney disease linked to long-term use or overdose.
THE THERAPEUTIC EFFICACY OF SODIUM NITRITE IN THE TREATMENT OF PATIENTS WITH CYANIDE POISONING DEPENDS UPON:
A) THE FORMATION OF METHEMOGLOBIN
B) AN INCREASE IN OXIDATIVE PHOSPHORYLATION
C) AN INCREASE IN CORONARY ARTERIAL BLOOD FLOW
D) A DECREASE IN INTRACRANIAL PRESSURE
E) RELAXATION OF THE NON-VASCULAR SMOOTH MUSCLE
ANSWER: A
For treatment of cyanide poisoning nitrite is administered to form methemoglobin.
This methemoglobin binds cyanide, sparing other critical cellular respiratory enzymes such as cytochrome oxidase.
Next sodium thiosulfate is administered, forming thiocyanide. The Thiocyanide is excreted.
IN ANTAGONIZING METHEMOGLOBINEMIA, METHYLENE BLUE
A) IS OXIDIZED FROM ITS REDUCED FORM & LEUCOMETHYLENE BLUES TO ITS OXIDIZED FORM
B) IS CONVERTED FROM ITS OXIDIZED FORM TO ITS REDUCED FORM BY NADPH
C) REDUCES THE IRON IN HEMOGLOBIN FROM FE+++ TO FE++
D) DISPLACES THE POISON FROM HEMOGLOBIN
E) IS OXIDIZED BY METHEMOGLOBIN REDUCTASE
ANSWER C:
Methylene blue reverses methemoglobinemia through activation of the NADPH-methemoglobin reductase pathway.
NADPH is produced in the hexose monophosphate shunt, an alternative
PRODUCES FATTY INFILTRATION AND CENTRILOBULAR NECROSIS OF THE LIVER AFTER SINGLE ACUTE EXPOSURE
A) BENZENE
B) ANILINE
C) METHANOL
D) CARBON TETRACHLORIDE
E) ETHYLENE GLYCOL
Carbon tetrachloride (CCl₄)
Fatty infiltration (steatosis) of the liver Centrilobular necrosis (damage centered around the central vein of liver lobules)
This damage occurs after a single acute exposure due to the formation of toxic free radicals during its metabolism by the cytochrome P450 enzyme system in the liver
Benzene: Primarily causes bone marrow suppression and leukemia.
Aniline: Associated with methemoglobinemia.
Methanol: Causes metabolic acidosis and optic nerve damage.
Ethylene glycol: Leads to renal failure due to oxalate crystal deposition
CHEMICALLY INDUCED LIVER DAMAGE IS OFTEN DETECTED HISTOLOGICALLY EVEN THOUGH ROUTINE LIVER FUNCTION TESTS DO NOT INDICATE ANY DAMAGE. THIS CAN OCCUR BECAUSE
1)THE LIVER IS CAPABLE OF REGENERATION OF LOST TISSUE
2) THE CHEMICAL WAS NOT AN HEPATOTOXIN
3) THE TOXICANT WAS CAUGHT UP IN THE ENTEROHEPATIC CYCLE
4) THE RESERVE FUNCTIONAL CAPACITY OF THE LIVER IS GREAT
4) THE RESERVE FUNCTIONAL CAPACITY OF THE LIVER IS GREAT
- BIOTRANSFORMATION OF THE PARENT COMPOUND TO AN ACTIVE METABOLITE THAT IS TOXIC TO THE LIVER IS CHARACTERISTIC OF THE FOLLOWING DRUG(S) /CHEMICALS) ?
A)HALOTHANE
B)BROMOBENZENE
C)CARBON TETRACHLORIDE
D)ACETAMINOPHEN
E) ALL OF THE ABOVE
All of them
Halothane – Metabolized in the liver to reactive intermediates
Bromobenzene – Undergoes metabolic activation by cytochrome P450 enzymes to form reactive epoxides, which bind covalently to liver macromolecules, leading to hepatotoxicity.
Carbon Tetrachloride (CCl₄) – Metabolized by cytochrome P450 to form the trichloromethyl radical (*CCl₃), which initiates lipid peroxidation and causes centrilobular necrosis.
Acetaminophen (Paracetamol) – Normally conjugated and excreted, but in overdose, it is metabolized to NAPQI, a highly reactive metabolite that depletes glutathione and causes massive hepatic necrosis
A particle 3 um in diameter is most likely deposited in
what part of respiratory system
A. nose
B. pharynx
C. trachea
D. bronchiolar
E. alveolar
D. Bronchiolar
> 10 µm: Mostly trapped in the nose and pharynx.
5–10 µm: Tend to deposit in the trachea and bronchi.
1–5 µm: Reach the bronchioles and alveoli.
<1 µm: May be exhaled or deposit in the alveoli via diffusion.
CARBON MONOXIDE
A) ACCUMULATES IN BLOOD THROUGH IRREVERSIBLE COMBINATION WITH HEMOGLOBIN
B) IS TAKEN UP BY THE BLOOD AT A RATE WHICH IS INITIALLY PROPORTIONAL TO THE CO CONCENTRATION IN THE RESPIRED AIR
C)IS DETOXIFIED BY METABOLISM TO FORM CARBON DIOXIDE
D) INCREASES OXYHEMOGLOBIN DISSOCIATION
E) TOXICITY IS DUE TO THE DECREASED CAPACITY OF TISSUE CELLS TO ABSORB OXYGEN
B) Correct – The uptake of CO by the blood is initially proportional to the concentration of CO in the inhaled air. This follows Henry’s Law, where gas absorption is proportional to its partial pressure.
- CO binds reversibly with hemoglobin to form carboxyhemoglobin
- CO not detoxified, eliminated unchanged
- CO shifts oxyhemoglobin dissociation curve to left so reduces oxygen release to tissue not increase
- Toxicity by binding hemoglobin (not direct on oxygen)
WHICH OF THE FOLLOWING IS CORRECT IN REGARD TO INHALATION EXPOSURE
A) DEPOSITION BY SEDIMENTATION OCCURS MAINLY WITH PARTICLES HAVING A MASS MEDIAN DIAMETER OF LESS THAN 1 MICRON
B) DEPOSITION BY DIFFUSION OCCURS PRINCIPALLY IN THE DEEP LUNG WHERE THE DIRECTIONAL CHANGES ARE MINIMAL
C) IMPACTION AT BIFURCATIONS OCCURS WHERE FLOW RATES ARE HIGHEST
D) B AND C ARE CORRECT
E) NONE ARE CORRECT
Answer: D
- Deposition by sedimentation of particles bigger than 1 Micron
- Deep Lung (Acinar Region): The deep lung, including the smaller conducting airways and alveoli, has a slower airflow rate and more prolonged residence time for inhaled particles
FUNCTIONING OF THE NERVOUS SYSTEM IN THE PRESENCE OF DAMAGE FROM TOXIC AGENTS IS POSSIBLE, IN LARGE PART, BECAUSE
1) THE NERVOUS SYSTEM POSSESSES CONSIDERABLE REDUNDANCY OF STRUCTURE
2) NEURONS IN THE CNS RETAIN THE CAPACITY TO DIVIDE THROUGHOUT THE LIFE OF THE ORGANISM
3) ADAPTATION OR TOLERANCE DEVELOPS TO SOME TYPES OF DAMAGE
4) GLIAL CELLS ARE TRANSFORMED INTO FUNCTIONING NEURONS
1 and 3 correct
Neurons in the CNS do not typically divide
adaptation or tolerance can occur in response to some neurotoxicants,
Glial cells do not transform into functioning neurons
TOCP (TRIORTHO CRESYL PHOSPHATE)
A) ACTIVE METABOLITE BINDS TO A NEUROTOXIC ESTERASE IN THE NERVOUS SYSTEM
B)INHIBITS PHENYL ACETATE HYDROLYSIS
C)CAUSES A DELAYED NEUROPATHY
D) ALL OF THE ABOVE
E)NONE OF THE ABOVE
Answer D: All of the Above
Principal target of TOCP (metabolized in liver) is NTE (Neurotoxic esterase)
inhibition of NTE by TOCP also leads to reduced hydrolysis of phenyl acetate,
TOCP causes organophosphate-induced delayed neuropathy (OPIDN), which typically appears 1–3 weeks after exposure,
ITS OXIDATION PRODUCT IS TOXIC TO RETINAL CELLS
ETHANOL
B) METHANOL
C) BOTH
D) NEITHER
Answer B
Alcohol dehydrogenase metabolizes methanol to formaldehyde
Aldehyde dehydrogenase metabolizes formaldehyde to formic acid
Formic acid causes acidosis and blindness
Treat methanol poisoning by inhibiting alcohol dehydrogenase and acidosis - ethanol
EVALUATION OF PRODUCTS FOR THEIR POTENTIAL TO CAUSE EYE INJURY IS TYPICALLY DONE USING ANIMAL MODELS. THE USE OF THE “LOW-VOLUME” TEST PROVIDES WHICH OF THE FOLLOWING ADVANTAGES OVER THE DRAIZE TEST?
A) BETTER CORRELATION TO HUMAN RESPONSE AND RECOVERY
B) REQUIRES THE USE OF LESS TEST MATERIAL
C) MORE HUMANE TREATMENT OF ANIMALS
D) A, B AND C
E) NONE OF THE ABOVE
A, B and C all True
THE LABORATORY SPECIES OF CHOICE FOR ASSESSING SKIN CONTACTALLERGENS IS THE
1. RABBIT
2. RAT
3. DOG
4. MOUSE
5. GUINEA PIG
Answer E - Guinea pig
Guinea pigs more sensitive
Magnusson and Kligman test (guinea pig maximization). Injected into skin along with Freund’s complete antigen.
ALLERGIC CONTACT DERMATITIS IS COMMON IN THE GENERALPOPULATION AFTER EXPOSURE TO:
A) LEAD
B)MERCURY
C) ZINC
D)NICKEL
E) CADMIUM
ANSWER D: NICKEL
Nickel is the most common cause of allergic contact dermatitis
WHICH OF THE FOLLOWING STATEMENTS REGARDING TOXIC RESPONSES OF THE SKIN IS NOT TRUE
A) ACUTE IRRITATION IS A REVERSIBLE LOCAL INFLAMMATORY RESPONSE CAUSED BY A SINGLE APPLICATION OF A TOXIC SUBSTANCE
B) CUMULATIVE IRRITATION IS AN IRREVERSIBLE INFLAMMATORY RESPONSE CAUSED BY REPEATED OR CONTINOUSEXPOSURE TO. TOXIC SUBSTANCE
C) PHOTOIRRITATION IS AN INFLAMMATORY RESPONSE CAUSED BY LIGHT-INDUCED MOLECULAR CHANGES IN A TOXIC SUBSTANCE
D) ALLERGIC CONTACT DERMATITIS GENERALLY INVOLVES A 10-21 DAY INDUCTION PERIOD BEFORE A RESPONSE MAY BE ELICITED
E) NONE OF THE ABOVE ARE TRUE
B) Not True – Cumulative irritation is typically reversible
Photoirritation occurs when a chemical on the skin is activated by light (usually UV), leading to an inflammatory response.
Allergic contact dermatitis does involve a sensitization (induction) period of about 10–21 days before the immune system mounts a response upon re-exposure.
Which of the following types of immunologic responses is NOT mediated by immunoglobulins?
A) type I (anaphylactic)
B) type II (cytolytic)
C) type III (arthus)
D) type IV (delayed-hypersensitivity)
E) type V (mixed)
Type I (anaphylactic): Mediated by IgE antibodies, which trigger mast cell degranulation (e.g., allergies, anaphylaxis).
Type II (cytolytic): Involves IgG or IgM antibodies targeting cell surface antigens
Type III (Arthus): Caused by immune complexes (IgG or IgM) deposited in tissues, causing inflammation (e.g., Arthus reaction).
Type IV (delayed-hypersensitivity): Driven by T cells, not immunoglobulins, with responses like contact dermatitis or tuberculin reactions.
Type V (mixed): Typically involves antibody-mediated responses
PRODUCES RENAL TUBULAR NECROSIS AND MYOCARDIAL SENSITIZATION TO SYMPATHOMIMETICS
A) CARBON MONOXIDE
B) NATURAL GAS
C) PROPYLENE GLYCOL
D) CARBON TETRACHLORIDE
E) CARBON DISULFIDE
D) Carbon Tetrachloride
Carbon tetrachloride is known to cause renal tubular necrosis due to its toxic metabolites, which damage the proximal tubules of the kidneys. It also sensitizes the myocardium to sympathomimetics, increasing the risk of cardiac arrhythmias, particularly in the presence of catecholamines.
A CNS POISON WHICH SELECTIVELY DAMAGES RETINAL CELLS IS?
A) WARFARIN
B) METHYL ALCOHOL
C) ARSENIC
D) CARBON TETRACHLORIDE
E) DISULFIRAM (ANTABUSE)
B) METHYL ALCOHOL
Methyl alcohol (methanol) is a CNS poison that is metabolized to formaldehyde and formic acid, which are toxic to retinal cells, leading to selective damage and potentially causing blindness.
THE PRIMARY MECHANISM FOR CLEARANCE OF INSOLUBLE PARTICLES
DEPOSITED IN THE LUNG PARENCHYMA IS?
A) CILIARY ACTIVITY IN THE MAJOR AIRWAYS
B) COUGH REFLEX IN DEEP LUNG
C) PHAGOCYTOSIS BY ALVEOLAR MACHROPHAGES
D) LYMPHATIC DRAINAGE
E) ENZYMATIC BREAKDOWN
C) Phagocytosis by alveolar macrophages is correct.
The primary mechanism for clearance of insoluble particles deposited in the lung parenchyma is phagocytosis by alveolar macrophages.
FACTORS WHICH AFFECT IRRITANT GAS-AEROSOL INTERACTIONS INCLUDE?
A) OXIDANT NATURE OF THE AEROSOL
B) SOLUBILITY OF GAS IN THE AEROSOL
C) CONCENTRATION OF SOLUTE IN AEROSOL
D) ALL OF THE ABOVE
E) NONE OF THE ABOVE
All are True
Oxidizing properties of the aerosol can influence how it interacts with irritant gases, potentially enhancing or altering their effects on tissues.
Solubility of gas in the aerosol: The solubility of the gas in the aerosol droplet affects how the gas is carried, deposited, or absorbed in the respiratory tract, influencing its irritant potential.
The concentration of solutes in the aerosol can affect its physical properties and how it interacts with gases, impacting deposition and irritation.
HEMORRHAGE IS A CHARACTERISTIC TOXIC EFFECT OF WHICH OF THE FOLLOWING?
A) THALLIUM
B) BENZENE
C) GASOLINE
D) CARBON TETRACHLORIDE
E) WARFARIN
E) Warfarin is correct.
Hemorrhage is a characteristic toxic effect of warfarin, an anticoagulant that inhibits vitamin K-dependent clotting factors (II, VII, IX, X), leading to excessive bleeding and hemorrhage.
WHICH OF THE FOLLOWING STATEMENTS IS CORRECT?
A) ALLYL ALCOHOL CAUSES CENTRILOBULAR NECROSIS
B) ACROLEIN CAUSES CENTRILOBULAR NECROSIS
C) ALLYL FORMATE CAUSES CENTRILOBULAR NECROSIS
D) ACROLEIN IS THE HEPATOTOXIC METABOLITE OF ALLYL ALCOHOL AND ALLYL FORMATE
E) ALL ARE CORRECT
Allyl alcohol is metabolized in the liver to acrolein, a highly reactive compound that causes centrilobular necrosis, due to its high metabolic activity.
B) Acrolein, a reactive aldehyde, is directly toxic to hepatocytes, leading to centrilobular necrosis either as a metabolite or as an administered compound.
C) Allyl formate is metabolized to allyl alcohol, which is further converted to acrolein, resulting in centrilobular necrosis similar to allyl alcohol.
D) Both allyl alcohol and allyl formate are metabolized in the liver to acrolein, which is the primary hepatotoxic metabolite responsible for causing centrilobular necrosis.
