TARGET ORGAN TOXICITY

Question 1

The impairment of hepatic function can have numerous negative consequences. Which of the following is likely NOT caused by impaired hepatic function?

Answer 1

Hyperglycemia

Question 2

Statements regarding the liver are true

Answer 2

• The major role of the liver is to maintain metabolic homeostasis of the body
• The liver encounters ingested nutrients before the heart does
• Hepatic triads contain a branch of the hepatic portal vein, a branch of the hepatic artery, and a bile ductile
• The large fenestrae of hepatic sinusoids facilitate exchange of materials between the sinusoid and the hepatocyte

Question 3

Activation of which of the following cell types can result in increased secretion of collagen scar tissue, leading to cirrhosis?

Answer 3

Ito cell

Question 4

Wilson’s disease is a rare genetic disorder characterized by the failure to export which of the following metals into bile?

Answer 4

Copper. Inability to export copper into bile is a central problem in Wilson’s disease, an autosomal recessive inherited disorder characterized by a defect in or the absence of a copper transporting P-type ATPase (ATP7B).

Question 5

Which of the following is NOT characteristic of apoptosis?

Answer 5

Cell swelling.
Though the necrotic cell swells and lyses, the apoptotic cell shrinks with condensation of nuclear and cytoplasmic materials, and cell breakage into membrane-bound fragments (apoptotic bodies) that are phagocytosed.

Question 6

A patient suffering from canalicular cholestasis would NOT be expected to exhibit which of the following?

Answer 6

Hydrophilic drugs readily diffuse into hepatocytes because of the large sinusoidal fenestrations.

Question 7

Which of the following statements regarding liver injury is FALSE?

Question 8

The inheritance of a “slow” aldehyde dehydrogenase enzyme would result in which of the following after the ingestion of ethanol?

Answer 8

Nausea

Question 9

Which of the following is NOT a common mechanism of hepatocellular injury?

Answer 9

increased transcytosis between hepatocytes.

Question 10

Ethanol is not known to cause which of the following types of hepatobiliary injury?

Answer 10

canalicular cholestasis. * Cholestasis is characterized by elevated serum concentrations of bile salts and bilirubin. This form of liver dysfunction is defined as a decrease in bile formation or an impaired secretion of specific solutes into bile.

Question 11

Role of mucus in the conducting airways?

Answer 11

• Pollutants trapped by mucus can be eliminated via expectoration or swallowing.
• Mucus is of a basic pH.
• The beating of cilia propels mucus out of the lungs.
• Free radical scavenging is believed to be a role of mucus

Question 12

Respiratory distress syndrome sometimes affects premature neonates due to lack of surfactant production by which of the following cell types?

Answer 12

type II pneumocytes. Type II pneumocytes are identified as the synthesizing cells of the alveolar surfactant, which has important properties in maintaining alveolar and airway stability. Lung surfactant can reduce the surface tension and prevent alveolar collapse and the airway walls collapse.

Question 13

In a situation where there is an increased metabolic demand for oxygen, which of the following volume measurements will greatly increase

Answer 13

Tidal volume (TV). Increases in tidal volume, minute ventilation, and minute O2 uptake can result in increased pulmonary distribution of gases and decreased time to reach alveolar steady state.

Question 14

The free radicals that inflict oxidative damage on the lungs are generated by all of the following EXCEPT:

Answer 14

SO2

Question 15

Which of the following gases would most likely pass all the way through the respiratory tract and diffuse into the pulmonary blood supply?

Answer 15

CO

Question 16

All of the following statements regarding particle deposition and clearance are true

Answer 16

• Lung defence is dependent on particle clearance. Once deposited in the lung, the adsorbed materials may dissolve from the surfaces of particles and enter the epithelium, endothelium, bloodstream, or lymphatics.
• Small particles (e.g., nanoparticles) may directly penetrate cell membranes and evade clearance. Moreover, particle clearance from the respiratory tract is not equivalent to clearance from the body. The only mechanisms by which deposited particles can be removed from the body are nasal wiping and coughing.
• Sedimentation controls deposition in the smaller bronchi, the bronchioles, and the alveolar spaces, where the airways are small, and the velocity of airflow is low.
• One of the main modes of particle clearance is via mucociliary escalation.
• Larger volumes of inspired air increase particle deposition in the airways.
• Sedimentation results in deposition in the bronchioles.
• Swallowing is an important mechanism of particle clearance.

Question 17

Which of the following is not a common location to which particles are cleared?

Answer 17

The pathological hallmark of pulmonary fibrosis is increased focal staining of collagen fibers in the alveolar interstitium, throughout the centriacinar region, including the alveolar ducts and respiratory bronchioles
A: increased type I collagen

Question 18

Pulmonary fibrosis is marked by which of the following?

Question 19

Activation of what enzyme(s) is responsible for emphysema?

Answer 19

Elastase

Question 20

Which of the following measurements would NOT be expected from a patient with restrictive lung disease?

Answer 20

Increased VC

Question 21

glufosinate

Answer 21

inhibition of glutamine synthetase.

Question 22

glyphosate

Answer 22

inhibition of amino acid synthesis.

Question 23

chlorophenoxy compounds

Answer 23

growth stimulants.

Question 24

diquat

Answer 24

production of superoxide anion through redox cycling.

Question 25

Captan

Answer 25

is a fungicide that could cause duodenal tumors.

Question 26

What is a mechanism of action of nicotine?

Answer 26

Nicotine exerts its effects by binding to nicotinic receptors located in ganglia, at the neuromuscular junction, and within the CNS, where the psychoactive and addictive properties most likely reside. Smoking and “pharmacological” doses of nicotine accelerate heart rate, elevate blood pressure, and constrict blood vessels within the skin. Nicotine acts as an ACh agonist in the synapse.

Question 27

Which of the following is the most characteristic of warfarin poisoning?

Answer 27

Hematomas

Question 28

Axons and/or axonal transport

Answer 28

Single nerve cells can be over 1 m in length.
Fast axonal transport is responsible for movement of proteins from the cell body to the axon.
Anterograde transport is accomplished by the protein kinesin.
The motor proteins, kinesin and dynein, are associated with microtubules

Question 29

Schwann cells in Wallerian degeneration

Answer 29

Schwann cells cells provide physical guidance needed for the regrowth of the axon.
Schwann cells release trophic factors that stimulate growth.
Schwann cells act to clear the myelin debris with the help of macrophages.
Schwann cells are responsible for myelination of axons in the peripheral nervous system.

Question 30

Prenatal exposure to ethanol can result in mental retardation and hearing deficits in the newborn. What is the cellular basis of the neurotoxicity?

Answer 30

microcephaly

Question 31

Which of the following characteristics is LEAST likely to place a neuron at risk of toxic damage?

Answer 31

ability to release neurotransmitters.

Question 32

The use of meperidine contaminated with MPTP will result in a Parkinson’s disease-like neurotoxicity. Where is the most likely site in the brain that MPTP exerts its toxic effects?

Answer 32

substantia nigra.

Question 33

PNS and the CNS

Answer 33

PNS axons can regenerate, whereas CNS axons cannot

Question 34

Platinum (cisplatin) results in which of the following neurologic problems?

Answer 34

peripheral neuropathy.

Question 35

characteristic of axonopathies?

Answer 35

There is degeneration of the axon.
The cell body of the neuron remains intact.
A majority of axonal toxicants cause motor deficits.
Sensory and motor deficits are first noticed in the hands and feet following axonal degeneration.
The neurotoxic disorders in which the primary site of toxicity is the axon are called axonopathies. The axon degenerates, including the myelin surrounding that axon; however, the neuron cell body remains intact. The toxicant causes a “chemical transection” of the axon at some point along its length, and the axon distal to the transection, biologically separated from its cell body, degenerates.

Question 36

Lead exposure

Answer 36

• Lead exposure results in peripheral neuropathy.
• Lead slows peripheral nerve conduction in humans.
• Segmental demyelination is a common result of lead ingestion.
• Lead toxicity can result in anemia.

Question 37

Excitatory amino acids

Answer 37

Glutamate is the most common excitatory amino acid in the CNS.
Excitotoxicity has been linked to conditions such as epilepsy.
Overconsumption of monosodium glutamate (MSG) can result in a tingling or burning sensation in the face and neck.
Glutamate is toxic to neurons.

Question 38

Which of the following cell types secretes anti-Müllerian hormone (AMH)?

Answer 38

Sertoli cell. which suppresses development of the paramesonephric (Müllerian) ducts, or female genital ducts.

Question 39

Penile erections are dependent on:

Answer 39

corpora cavernosa smooth muscle relaxation.

Question 40

The corpus luteum is responsible for the secretion of which of the following hormones during the first part of pregnancy?

Answer 40

Progesterone and estradiol

Question 41

The hypothalamo-pituitary–gonadal axis

Answer 41

• FSH and LH are synthesized in the anterior pituitary.
• Estradiol provides negative feedback on the hypothalamus and the anterior pituitary.
• GnRH from the hypothalamus increases FSH and LH release from the anterior pituitary.
• The LH spike during the menstrual cycle is responsible for ovulation.

Question 42

Gametal DNA repair

Answer 42

• DNA repair in spermatogenic cells is dependent on the dose of chemical.
• Spermiogenic cells are less able to repair damage from alkylating agents.
• Female gametes have base excision repair capacity.
• Meiotic maturation of the oocyte decreases its ability to repair DNA damage.

Question 43

Reduction division takes place during the transition between which two cell types during spermatogenesis?

Answer 43

primary spermatocyte and secondary spermatocyte.

Question 44

Which of the following cell types is properly paired with the substance that it secretes?

Answer 44

gonadotroph—LH.

Question 45

Male reproductive capacity

Answer 45

• Klinefelter’s syndrome males are sterile.
• FSH levels are often measured in order to determine male reproductive toxicity of a particular toxin.
• Divalent metal ions, such as Zn, Hg, and Cd, can affect male reproduction.
• ABP is an important biochemical marker for testicular injury.

Question 46

Reduction of sperm production can be caused by

Answer 46

• Crohn’s disease
• Hypothyroidism
• renal failure.
• mumps.

Question 47

LEAST likely to be affected by estrogen?

Answer 47

digestive system.

Question 48

The inability to release hormones from the anterior pituitary would affect the release of which of the following?

Answer 48

• LH: Luteinising hormone
• PRL: Prolactin
• TSH: Thyroid-stimulating hormone
• ACTH: Adrenocorticotrophic hormone

Question 49

pituitary hormones

Answer 49

The function of chromophobes in the anterior pituitary is unknown

Question 50

21-Hydroxylase deficiency causes masculinization of female genitals at birth by increasing androgen secretion from which region of the adrenal gland?

Answer 50

zona reticularis.

Question 51

Adrenal toxicity

Answer 51

The adrenal cortex and adrenal medulla are equally susceptible to fat-soluble toxins.

Question 52

Chemical blockage of iodine transport in the thyroid gland

Answer 52

mimics goiter.

Question 53

Chromaffin cells of the adrenal gland are responsible for secretion of

Answer 53

epinephrine.

Question 54

The parafollicular cells of the thyroid gland are responsible for secreting a hormone that:

Answer 54

increases bone resorption.

Question 55

Parathyroid adenomas resulting in increased PTH levels would be expected to cause which of the

Answer 55

osteoporosis.

Question 56

Which vitamins increases calcium and phosphorus absorption in the gut?

Answer 56

niacin. Niacin is a B vitamin that’s made and used by your body to turn food into energy. It helps keep your nervous system, digestive system and skin healthy.

Question 57

Glucose control

Answer 57

• Glucagon stimulates glycogenolysis, gluconeogenesis, and lipolysis.
• Insulin stimulates glycogen synthesis, gluconeogenesis, and lipolysis.
• Insulin promotes storage of glucose, fatty acids, and aminoacids by their conversion to glycogen, triglycerides, and protein, respectively.
• Insulin and glucagon exert opposing effects on blood glucose concentrations.