two simple bio questions

[gomawum]

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1. plama cells produce antiobody, but the B-lymphocyte produce antibody
are they the same thing?

2. kaplan book says that "resting potential is created because the neron is SELECTIVELY PERMEABLE that is K+ diffuse dowm gradients while Na+ is impermeable."

but the picture shows that Na+ is also somewhat permeable

can someone elaborate these two concepts?

 

[joonkimdds]

1. plama cells produce antiobody, but the B-lymphocyte produce antibody
are they the same thing?

If B cell is starting to produce antibody, that is called plasma cell.
if b cell isn't making antibody, it's not plasma cell.

 

[War Eagle]

Not sure about the first question, but maybe I can help you with the second. K is mainly responsible for the RMP. If you check out the Nernst values for K and Na, you'll find that K has a value of about -90 and Na about +60 (I haven't looked at those numbers for a while so they may be a little off, this is just off the top of my head). The RMP is about -70 (closer to the nernst value for K). Remember that the Nernst potential is the value that will result if the ions can go to equilibrium (If K channels are open, the K efflux will cause the cell to reach a potential of -90. This is what is responsible for the undershoot of the action potential). You are always going to have different ions flowing, and chances are that there is some Na movement. The thing is that the membrane is 40 times more permeable to K than to Na!!! This is why the RMP is so much closer to the Nernst value for K than to that of Na. That is probably why they say that it is impermeable to Na. NaKAtPase also plays a large role in maintaining the RMP.

 

[tinman831]

1. plama cells produce antiobody, but the B-lymphocyte produce antibody
are they the same thing?

B cells mature into antibody secreting plasma cells.

 

[bigstix808]

Not sure about the first question, but maybe I can help you with the second. K is mainly responsible for the RMP. If you check out the Nernst values for K and Na, you'll find that K has a value of about -90 and Na about +60 (I haven't looked at those numbers for a while so they may be a little off, this is just off the top of my head). The RMP is about -70 (closer to the nernst value for K). Remember that the Nernst potential is the value that will result if the ions can go to equilibrium (If K channels are open, the K efflux will cause the cell to reach a potential of -90. This is what is responsible for the undershoot of the action potential). You are always going to have different ions flowing, and chances are that there is some Na movement. The thing is that the membrane is 40 times more permeable to K than to Na!!! This is why the RMP is so much closer to the Nernst value for K than to that of Na. That is probably why they say that it is impermeable to Na. NaKAtPase also plays a large role in maintaining the RMP.

^^ think that the bold is key. All valves that regulate Na K flow are slightly leaky. That is a key reason on why we have NAK pumps to keep the membrane potential constant.

 

[jntruong2003]

ditto w/ bigstix. nice videos btw. they were awesome! DAT in 2 days...gulp!