Someone explain this biology question to me

[Timbo]

Under certain conditions, the herb ephedra can cause cardiac arrhythmias and seizures, mostly likely because it has an effect on
A. humoral immunity
B. the sympathetic nervous system
C. cell-mediated immunity
D. the parasympathetic nervous system

I have no idea what ephedra is; never seen it in any review books, never heard of it in any bio classes, so I'm assuming they expect us to solve this based on the fact that it causes "arrhythmias and seizures." From that I immediately know it's either B or D. Now I know the sympathetic NS increases heart rate and parasympathetic decreases heart rate, however arrhythmias can either be the heart beating too fast or too slow, so no help there. So I figure seizures would be caused by low blood supply to the brain, so that would be caused by low heart rate, so I chose answer D, parasympathetic nervous system.

WRONG. turns out the correct answer is B. What should my reasoning have been?

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[harmonidrum]

Ephedra is a CNS stimulant. If you've read any newspapers in the past 10 years, you'd know that it is a regulated substance due to its being a methamphetamine precursor. Stimulants activate the sympathetic nervous system.

 

[Timbo]

Ephedra is a CNS stimulant. If you've read any newspapers in the past 10 years, you'd know that it is a regulated substance due to its being a methamphetamine precursor. Stimulants activate the sympathetic nervous system.

I guess people know about it.. . I kind of feel like an ignoramus for never hearing about it. I do read the news and have been for these past few years, just not when i was 12 years old

 

[Incitatus]

Ephedra is a CNS stimulant. If you've read any newspapers in the past 10 years, you'd know that it is a regulated substance due to its being a methamphetamine precursor. Stimulants activate the sympathetic nervous system.

Wow, this was completely unnecessary.

 

[pharmschooler]

Ephedra is a CNS stimulant. If you've read any newspapers in the past 10 years, you'd know that it is a regulated substance due to its being a methamphetamine precursor. Stimulants activate the sympathetic nervous system.

You presume a lot. Ephedra's been off the market for a long time now (since the early 2000s). A younger student most likely would not have heard of it since it hasn't made the news in a long time. Think about it: a 20 year old would have been about 12 the last time it was really making news. I don't think they could be faulted for not remembering/knowing anything about ephedra. Many pharmacy applicants also grew up outside the United States. I highly doubt ephedra was a big story in China.

 

[MolarExpress]

Under certain conditions, the herb ephedra can cause cardiac arrhythmias and seizures, mostly likely because it has an effect on
A. humoral immunity
B. the sympathetic nervous system
C. cell-mediated immunity
D. the parasympathetic nervous system

I have no idea what ephedra is; never seen it in any review books, never heard of it in any bio classes, so I'm assuming they expect us to solve this based on the fact that it causes "arrhythmias and seizures." From that I immediately know it's either B or D. Now I know the sympathetic NS increases heart rate and parasympathetic decreases heart rate, however arrhythmias can either be the heart beating too fast or too slow, so no help there. So I figure seizures would be caused by low blood supply to the brain, so that would be caused by low heart rate, so I chose answer D, parasympathetic nervous system.

WRONG. turns out the correct answer is B. What should my reasoning have been?

Arrhythmias are associated with an overstimulation of the sympathetic nervous system. You don't need to know much about ephedra itself to answer this question.

 

[harmonidrum]

Arrhythmias are associated with an overstimulation of the sympathetic nervous system. You don't need to know much about ephedra itself to answer this question.

This is incorrect. The OP is correct when he states that over stimulation of the parasympathetic as well as the sympathetic can both be responsible for inducing arrhythmia. In this case ephedra can cause extreme tachycardia to the point of heart failure. Tachycardia is associated with sympathetic agonists.

 

[Incitatus]

This is incorrect. The OP is correct when he states that over stimulation of the parasympathetic as well as the sympathetic can both be responsible for inducing arrhythmia. In this case ephedra can cause extreme tachycardia to the point of heart failure. Tachycardia is associated with sympathetic agonists.

Right. Arrythmias can be caused by a number of factors including ion concentration in the blood (which itself can have innumerable causes), (Para)sympathetic over stimulation, etc.

The key thing to note is that arrythmias are "A-Rythmic."

 

[Praziquantel86]

Just a friendly reminder to please keep discussions civil. Thanks!