pt 4

Question 1

The greater susceptibility may of nervous system to toxicity is attributed to
Partly to:
-the fact that neurons have a (1)—- metabolic rate, with little capacity for (2)——–

-Furthermore, being electrically excitable, neurons tend to lose cell membrane integrity more readily.

-The great length of the axons is another reason why the nervous system is especially susceptible to toxic effects, because the cell body must supply its axon structurally and metabolically

Answer 1

(1) high
(2) anaerobic metabolism

Question 2

what drugs produce brain anoxia

Answer 2

BARB

Question 3

Contamination of food products with tricresyl phosphate was shown to produce a delayed neuropathy related to inhibition of “neuropathy target esterase” whereby there is damage to spinal nerves, the spinal cord, brain, and other tissues
This type of neuropathy also occurs following exposure to organophosphorous
insecticides

Answer 3

tricresyl phosphate

Question 4

The cell body of neurons may be affected directly by toxicants such as ——

Answer 4

methyl mercury

Question 5

The paraquat-induced neuronal effects resemble the manifestations in ——–disease.

Answer 5

Parkinson’s

Question 6

—– affects neurons by intercalating with DNA, leading to a breakdown of the helical structures inhibits the synthesis of RNA and neuronal protein

Since this drug does not cross the BBB, it can affect the neurons in the dorsal
root ganglia and autonomic ganglia, but not those in the CNS.

Answer 6

Doxorubicin

Question 7

Some axons are very long (up to 1 m), and the elements in the axons, such as ——-, are synthesized not locally but in the cell body, and are transported along the axon.

Answer 7

neurofibrils

Question 8

β, β-Iminodiproprionitrile (IDPN) produces —–

Answer 8

Proximal Axonopathy: typical lesions through impairment of slow axonal transport of neurofilaments (phosphorylation)

Question 9

what agents lead to CNS mitochontrial swelling

Answer 9

thallium

Question 10

distal axonopathy is caused by ——

Answer 10

-organophosphates (TOCP (tri-o-cresyl phosphate), EPN, and leptophos) lead to DELAYED NEUROPATHY

-n-hexane and methyl n-butyl ketone

and organic solvents

Question 11

Tetrodotoxin, the toxic principle of puffer fish, has been shown to block the action potential by blocking the ——–

Answer 11

Na+ channels

-Interference with Impulse Conduction

Question 12

MOA of Clostridium botulinum: producing paralysis of muscles by impairing the release of (1) ——- from motor nerve endings

Answer 12

Interference with synaptic transmission

(1) acetylcholine

Question 13

how does Black widow spider venom interfere with synaptic transmission

Answer 13

produces an excessive release of acetylcholine and results in cramps and paralysis

Question 14

——- produces neurotoxicity by interfering with kinesin-related motor proteins in neurofilaments that are involved in fast antegrade transport of nerve signals between axons

Answer 14

Acrylamide

-This is manifested as hindlimb splay, ataxia, and skeletal muscle weakness

Question 15

lead affects Schwann cells possibly by interfering with their —- transport

Answer 15

Ca2+

The PNS is affected before the CNS due to lead. In addition, lead affects motor nerves before the sensory, resulting in “wrist-drop” and “foot-drop.”

Question 16

——- disrupt myelin sheath because of the high (70%) lipid content of myelin.

Answer 16

Hypocholesterolemic agents such as triparanol,

Question 17

The pesticide ——- produces degeneration of the GANGLION CELL LAYER resulting in a neurodegerative disorder associated with destruction of the MITOCHONDRIA.
-This phenomenon is found in Leber’s optic neuropathy and Parkinson’s disease.

Answer 17

rotenone

Question 18

Acetyl ethyl tetramethyl tetralin (AETT) causes ——– through a complex mechanism

Answer 18

myelinopathy

Question 19

Clostridium botulinum, Black widow spider venom, acrylamide. lead to

Answer 19

Interference with synaptic transmission

Question 20

TRIparanol, Diphtheria toxin, rotenone, Acetyl ethyl tetramethyl tetralin (AETT).

they cause

Answer 20

Glial cells and myelin

Question 21

lead, mercury, arsenicals, tellurium (in the endonerium), are associated with ——- toxicity

Answer 21

EXTRAcellular edema

Question 22

Various parts of neurons may become edematous (CELLULAR EDEMA) following exposure to toxicants

Answer 22

-6-aminonicotinamide affects the perikaryon

-cyanide and carbon monoxide affect the axon

-ouabain and methylsulfoxime affect the presynaptic nerve endings.

Question 23

——— produce, after acute exposure, narcosis, but they induce axonopathy after repeated exposures

Answer 23

n-hexane and TOCP

Question 24

ammonia, chlorine, arsnicals lead to

Answer 24

lung local irritation

Question 25

what are toxicants that lead to cellular damage of lungs and edema, and what is their MOA?

Answer 25

Toxic gases, such as ozone and oxides of nitrogen, produce cellular damage, perhaps through generation of reactive oxygen species followed by peroxidation of cellular membranes.

Question 26

the lung serves as a conduit for chemicals into the circulation followed by activation in other tissues and development of diseases in different organs. such as ——— that enters via the lung, forms reactive intermediates in the liver, and these intermediates react with bone macromolecules subsequently resulting in leukemia

Answer 26

benzene

Question 27

On heating, such as in volcanic eruption and mining, quartz may become tridymite or cristobalite. Both of these forms are more fibrogenic than quartz.
The toxic effect stems from the ——- in a macrophage. The released lysosomal enzymes digest the macrophage, and this process, in turn, releases the silica from the lysed macrophage.

Answer 27

rupture of the lysosomal membrane

Question 28

Another major cause of pulmonary —— is asbestos.
Asbestos refers to a large number of fibrous hydrated silicates of magnesium, calcium, and others.

Answer 28

fibrosis

Question 29

——– is also a debilitating disease. It may be induced by cigarette smoking or exposure to aluminum, cadmium oxide, or oxides of nitrogen, ozone, and others.

Answer 29

Emphysema

Question 30

It was suggested that the elastic fibers surrounding and supporting the alveoli and bronchi may be damaged by the ———– under certain conditions

Answer 30

elastase released from polymorphonuclear (PMN) granulocytes

Question 31

Large airborne particles in the inhaled air are mainly deposited in the nasal passages and cause

Answer 31

They may produce hyperemia, squamous- or transitional-cell metaplasia, hyperplasia, ulceration, and, in certain cases, carcinoma.

Question 32

closely related herbicide to paraquat, ——-, although also toxic to cultured lung cells, is not toxic to the lungs either after inhalation or after ingestion.

Answer 32

diquat

Question 33

food colors, pesticides (e.g., DBCP), plastics (phthalates), metals (e.g., arsenic, tin, lead, and cadmium), and organic solvents.
A variety of other chemicals affect the ——, such as steroid hormones, alkylating agents, cyclohexylamine, and hexachlorophene.

Answer 33

testis

Question 34

both
methylmethane sulfonate (MMS) and
busulfan
produce lethal mutations

Answer 34

but MMS affects spermatids and spermatozoa whereas busulfan affects the prespermiogenic cells. These alkylating agents apparently attack the DNA of these cells with different repair mechanisms

Question 35

Tumors may develop in the testis. For example, the herbicide – may induce Leydig cell tumors.

Answer 35

linuron

Question 36

—— has been reported to induce prostate cancer in men

Answer 36

Cadmium

Question 37

Oocytes may be damaged by chemotherapeutic agents such as

Answer 37

nitrogen mustard and vinblastine, and polycyclic aromatic hydrocarbons (PAH) such as 3-methylcholanthrene and benzo[a]pyrene.

Question 38

• ——– prevents implantation
• ——– may interfere with ovulation and implantation of the fertilized ovum; it may also retard the development of the sex organs of the offspring

Answer 38

-Haloperidol

-Spironolactone

Question 39

——– suppresses ovarian steroid hormone secretion, interrupts regular cyclicity and inhibits embryo implantation

Answer 39

Gossypol is also toxic in the female.

Question 40

vitamins and nutrient deficiencies and cobalt, and poisons lead to —— tox

Answer 40

hemato system

Question 41

Dichloromethane exposure can also cause asphyxia hypoxia as metabolite is ——-

Answer 41

carbon monoxide!

Question 42

—– will cause oxidation of the haemoglobin to cause methaemoglobin which is unable to carry oxygen

Answer 42

Aniline