synapse question

[Gordon9721]

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i still can't see the reasoning and logic behind this question. maybe someone can shine some light on it for me.

A rectifier is an electrical device that allows current to flow in only one direction. In human physiology, an analogous device is the:
a-axon
b-dendrite
c-synapse
d-schwann cell
e-spinal nerve

The answer is C. But i thought that the axon, dendrite, and synapse all act together to promote impules in one direction only. I'm obviously wrong, but I don't understand why. A little assistance please?

 

[Gordon9721]

man, no one wants to answer my question........
is it that stupid?

 

[Uracil]

To be honest, I would have put axon as the answer because it is the axon that transmitts the Action Potential signal in only one direction.

But since it is talking about the rectifier, it might be a synapse because synapses allow the neurons to communicate as an "electrical circuit", just like rectifiers.

I hope someone can elaborate more on this for you. That's all I can come up with.

 

[allstardentist]

i remember this question from barrons (i think). i also think the answer should be axon because it transmits Action potential in one direction due to electrochemical gradient while what happens at synapse is only due to neurotransmitter (chemical). but im not totally sure how rectifier works. so i could be wrong. but on the real DAT, you will only have questions with clear-cut answer

 

[Clover]

i believe it's a kaplan question and the answer was synapse

in a synapse, neurotransmitter is released from pre-synaptic terminal to post synaptic terminal.

since neurotransmitters bind to receptors, and only the post synaptic membrane has the receptors, excitation can only occur in one direction:

pre-synpatic --> synaptic cleft (synapse) --> post-synaptic

axons can be excited in both directions: towards cell body (retrograde) or away from cell body (anterograde)

however, once an action potential has been initiated, that AP can only traverse the axon in one direction . . . b/c of you know, sodium channels behind it yadda yadda

hope this helps

i got tricked by this one too . . but then i don't know what a rectifier is

 

[tinman831]

Clover is right. If a electric stimulus was placed in the middle of an axon, the current could travel in both directions.

 

[Gordon9721]

clover and tinman: thanks
BUT!

why would the electric stimulus be placed in the middle of the axon? i thought that all impulses from a synapse hit the dendrite then the soma then sent out with the axon. i don't think it needs to go any deeper with information than what we got right now, but i'm just kind of curious, i thought i had a grasp on this neurononsense. can acetylcholine be sent out of the presynaptic cleft and then for whatever reason be pushed back and send an impulse backwards? o man. getting too deep into it.

btw clover, high scores on the DAT. how'd you do that? i take mine saturday the 30th, nervous as hell. and my gpa's are similar to yours, lower bcp (2.65) but higher gpa (3.3). any interviews or anything yet?

it was a kaplan question, also.

 

[Clover]

why would the electric stimulus be placed in the middle of the axon?
-- experimental data?? by using an electrode to induce an AP, i think


can acetylcholine be sent out of the presynaptic cleft and then for whatever reason be pushed back and send an impulse backwards?
-- reuptake occurs at the presynaptic terminal but acetylcholine gets degraded. specifics not sure about


how i did it? . . studying hard and good mentor 🙂love: Dr. R)
and 1 interview at columbia

btw, good luck on your exam -- you'll do WONDERFUL!

 

[allstardentist]

i read somewhere that AP travels from cell body to synapse. but i could be wrong.

 

[mightymouse23]

why would the electric stimulus be placed in the middle of the axon?
-- experimental data?? by using an electrode to induce an AP, i think


can acetylcholine be sent out of the presynaptic cleft and then for whatever reason be pushed back and send an impulse backwards?
-- reuptake occurs at the presynaptic terminal but acetylcholine gets degraded. specifics not sure about


Dont forget that acetylcholine can be re-uptaken rather than degraded. I think what this question is asking is if a stimulus is being provided (ie the electric current from the rectifier), where would it be applied best to show movement in one direction. Based on that it would have to be the synapse since the stimulus there (acetylcholine) would have to bind to receptors to produce a ESPS. When it is re-uptaken, it doesnt generate any action potential... Might need to ask Amsie for this, but im sure she is passed out drunk in NY 😀

Sag

 

[RICEman]

i still can't see the reasoning and logic behind this question. maybe someone can shine some light on it for me.

A rectifier is an electrical device that allows current to flow in only one direction. In human physiology, an analogous device is the:
a-axon
b-dendrite
c-synapse
d-schwann cell
e-spinal nerve

The answer is C. But i thought that the axon, dendrite, and synapse all act together to promote impules in one direction only. I'm obviously wrong, but I don't understand why. A little assistance please?

I thought potassium channels (in the axon) are also called "delayed rectifiers"???

 

[RICEman]

i still can't see the reasoning and logic behind this question. maybe someone can shine some light on it for me.

A rectifier is an electrical device that allows current to flow in only one direction. In human physiology, an analogous device is the:
a-axon
b-dendrite
c-synapse
d-schwann cell
e-spinal nerve

The answer is C. But i thought that the axon, dendrite, and synapse all act together to promote impules in one direction only. I'm obviously wrong, but I don't understand why. A little assistance please?

I thought potassium channels (in the axon) are also called "delayed rectifiers"???

 

[Gordon9721]

i don't think knowing what a rectifier is really has any importance