Scioly.org

Hey this is my first year in Science Olympiad so I was just wondering where I could start in order to begin studying for the Nervous/Integumentary/Immune systems. Is simply reading the requirements and going by those sufficient? And if so, where can I find information for these?

PS I went to the links on the page about Anatomy and Physiology for group C and I could only find a few links that seemed actually useful for me.
Thanks for the help!

Hey friend,

I would start by going with what's in the rules. What's there is everything you need to know about, and everything you need to know about (aka you don't need to know anything else). I would, though, go ahead and check out the Nationals stuff, as many State/Regional coordinators will pick those topics anyways. Going outside of the rules in studying never hurts either, but it's an imperative and higher priority that you know what's listed in the rules.

As to actually studying, I believe the wiki has a decent page for the Nervous system, starting there would be good. Taking what's in the rules/checking a few anatomy books out from the library can get you started on the basics of Integumentary system (from there, I looked more up via the web). Since I'm not actually doing Immune, I don't have any advice in particular, but some of the above strategies should work. The internet is a beautiful thing

Taking notes to enforce what you're reading is a good idea, like always. Another good strategy is to take tests off the Test Exchange with your partner, and go over and study what you've missed. Another cool idea is to split up the systems so that you're focusing on one system while the other is on another. With the C team, you have an unfortunate three, an uneven number, but I'm sure there's some way to work it out.


In short, I'm telling you how to study and use the Internet. I think you could do it yourself, first.

HOH,
Red

I thought I understood action potentials but now i"m confused...
I learned that the sodium potassium pump restores the resting potential in axons by removing 3 sodium ions and adding 2 potassium ions back into the cell interior.
But wouldn't that make the interior of the cell more negative? How would that help if the cell is hyperpolarized?

And also, which ion channels are open and which are closed? Am I right in saying that the ligand gated potassium channels are open in the postsynaptic terminal, but all voltage gated channels are closed in the axon? If that's true, then ions can only freely diffuse back and forth in the postsynaptic terminal? So the sodium-potassium pump would also have to maintain ion gradients there as well as in the axons?

Sorry about all the questions! I'm probably making this more complicated than it should be

fanjiatian wrote:I thought I understood action potentials but now i"m confused...
I learned that the sodium potassium pump restores the resting potential in axons by removing 3 sodium ions and adding 2 potassium ions back into the cell interior.
But wouldn't that make the interior of the cell more negative? How would that help if the cell is hyperpolarized?

And also, which ion channels are open and which are closed? Am I right in saying that the ligand gated potassium channels are open in the postsynaptic terminal, but all voltage gated channels are closed in the axon? If that's true, then ions can only freely diffuse back and forth in the postsynaptic terminal? So the sodium-potassium pump would also have to maintain ion gradients there as well as in the axons?

Sorry about all the questions! I'm probably making this more complicated than it should be

I'm sorry, what? I have no idea where you're coming from Maybe this is what you're looking for

The sodium-potassium pump doesn't exactly RESTORE the cell membrane potential - it just plays a role in keeping it there. It's part of the reason why the cell membrane, at rest, has a voltage across it. The electrogenicity of the pump is what maintains the voltage - it pumps 3 Na+ ions out (that leak in) and 2 K+ ions in (that leak out). So there's a net loss of positive charge on the inside of the cell membrane. Other factors that contribute to the RMP include the permeability of the membrane (there are more K+ leak channels than Na+ leak channels. K+ flows down its electrochemical gradient into the ECF, while Na+ flows down its gradient into the cytosol. Since more K+ flows out than Na+ flows in...) as well as the fact that most of the anions are attached to non-diffusable molecules such as ATP and large proteins, so they cannot follow K+ out of the cell very easily.

The cell returns to normal RMP after hyperpolarization by simply closing its potassium channels. That stops the extra outward flow of K+ and returns the membrane potential to normal.

Do you mean dendrites by "postsynaptic terminal"? Eh I'm just gonna assume that since it'll make my life easier. Ligand-gated potassium channels in the dendrites would open in response to a neurotransmitter which binds to the receptor on the/associated with the channel (and thus would produce an inhibitory post-synaptic potential, but that's beside the point). I don't think it has much of a role in maintaining the ion gradient, it really just serves to inhibit the neuron's activity. Voltage-gated channels in the axonal membrane contribute to an action potential, not the RMP, and only open when a certain voltage (threshold) is reached.

Is this all making sense? It sounds like you've got a few misconceptions here or there, need anything else explained?

Oh! I see now
So the resting potential is restored just by closing potassium channels, not the pump? I guess I'm confused about when the pump works. Does it work at the resting potential? Would that imply that leak channels are open at rest?
Haha yeah, I meant dendrites! So the purpose of the postsynaptic potential is just to trigger or inhibit the production of action potential at the axon hillock? Does the pump work there as well?

Thanks so much! Maybe it's just me, but some of the online resources contradict each other, which might explain my confusion

fanjiatian wrote:Oh! I see now
So the resting potential is restored just by closing potassium channels, not the pump? I guess I'm confused about when the pump works. Does it work at the resting potential? Would that imply that leak channels are open at rest?
Haha yeah, I meant dendrites! So the purpose of the postsynaptic potential is just to trigger or inhibit the production of action potential at the axon hillock? Does the pump work there as well?

Thanks so much! Maybe it's just me, but some of the online resources contradict each other, which might explain my confusion

I think you're overthinking this a bit. The sodium-potassium pump kinda works to "replenish" the the Na+ and K+ ions that have flown down their electrochemical gradients. I suppose you could say that they work at all times, but their only significant role is in establishing the neuron's RMP. Once you start getting into action potentials, you're really just looking at the voltage-gated channels in the axon membrane; for graded potentials, primarily ligand-gated channels in the dendrites.

Does anyone know what systems are tentatively scheduled for C division next year?

strawberrygirl wrote:Does anyone know what systems are tentatively scheduled for C division next year?

I don't think anyone knows yet; the earliest event notification I've seen was after state. Integumentary system is definitely one of them though...

Could you guys help explain how a impulse works, with the Na+ and K+ transfer? I don't get it

The tests in Arizona have been completely erratic this year!!! Most of the other tests are pretty much the same over the course of the year, but Anatomy has been all over the map!!! Has anyone else experienced this? Note: I am in Division B.