nervous system tox

Question 1

what are some features of the nervous system that are related to how its affected by toxicants

Answer 1

• the blood brain barrier
• high energy requirements of the brain
• extedned cellular geomtery - very unique
• myelination
• transmission of info across a gap
• regenrative pattern of the nervous system

Question 2

what maintains the blood brain barrier?

Answer 2

specialized endothelilal cells in the microvasculature.
—- tight junctions between the cells

Question 3

what determines whether toxicants can get through the BBB?

Answer 3

the lipid solubility

the activity of the transporters that are expressed in the BBB

Question 4

what is unique about the circumventricular regions of the brain; whats the significance of this wrt toxicants?

Answer 4

it doesn’t have tight jucntions.

this lets the brain respond to circulating blood hormones, but also lets some toxic chemicals enter.

Question 5

the BBB is not fully developed at birth. what relevance does this have?

Answer 5

some compounds are toxic to neonates only.

Question 6

t/f: neurons have low metabolic requirements

Answer 6

false! they have high metabolic demand to maintain and reestablish ion gradients.

Question 7

t/f: neurons use anaerobic respiration so they can utilize energy fast

Answer 7

false. they require aerobic respiration.

Question 8

neurons are post mitotic - what does this mean

Answer 8

they cant divide, but they keep growing.

Question 9

t/f: neurons have high energy requirements therefore have internal energy reserves

Answer 9

false. they have continuous energy demand but no internal energy reserves.

Question 10

what mediates fast transport vs slow components in nerve cells

Answer 10

the fast: microtubule assoc ATPase activity and motor protiens like kinesin and dyenin.

slow: the slow components are

Sca neurofilaments and microtubules
Scb sre structural proteins, actin, soluble proteins.

Question 11

which cells produce myelin

Answer 11

oligodendrocytes and schwann cells

Question 12

how is actin remodelling related to myelination; roles of F actin vs G actin

Question 13

how is the myelin sheath maintained generally, and in the PNS vs CNS

Question 14

how does neurotransmission occur

Question 15

how do toxicants dirupt neurotransmission

Question 16

t/f: toxicants always induce short term, reversible dysfunction in neurotransmission

Question 17

how does chemical exposure early vs late in development affect the brain differently

Question 18

t/f: myelin cells are the first to develop

Question 19

what happens in the brain growth spurt

Question 20

what are the 4 mechanistic classes of neuronal toxicity

Question 21

what happens in neuronopathy

Question 22

what happens in axonopathy

Question 23

what happens in myelinopathy

Question 24

what happens in transmission toxicty

Question 25

how does MPTP toxicity occur -- where does it act?

Question 26

how does dopamine autooxidation occur? why is this bad?

Question 27

what type of -pathy does MPTP cause

Question 28

what toxins produce axonopathies

Question 29

how does n hexane lead to axonopathy

Question 30

how does carbon disulfide lead to axonopathy

Question 31

myelinopathies can be cause by toxins that produce either ___ or ___-

Question 32

what happens in intramyelinic edema

Question 33

what protein level fluctations are involved in intramyelinic edema

Question 34

t/f: intramyelinic edema is irreversible, even in early stages

Question 35

how does demyelination occur?? is it always related to intramyelinic edema?

Question 36

which -pathy can hexachlorophene lead to

Question 37

how does hexachlorophene lead to intramyelinic edema

Question 38

what are the 7 molec mechanisms by which toxicants can alter chemical neurotrans

Question 39

what type of neuro -pathy or tox do insecticides fall under

Question 40

t/f: all types of insecticides used today are neurotoxicants

Question 41

how do organophosphates cause neurotox

Question 42

what are the signs of AchE inhibitor acute poisoning

Question 43

what is the difference between P=O and P=S insecticides

Question 44

what reactions can detoxify OP insectisides

Question 45

t/f: all cyps have the same selectivity for bioactivation/detox for all OPs

Question 46

how are OP insectisides bioactivated

Question 47

how are OP insecticides detoxified

Question 48

how do OPs lead to irreversible AchE inhibition

Question 49

how do PCBs lead to neurotoxicity

Question 50

how does Pb (lead) lead to neurotox

Question 51

neuroinflammation is a response to brain injury. how does it occur, and what disorders is it assoc with