I've seen videos that explain this in half hour time to an hour, thank you you condensed it nicely in 3 minutes and very well explained.
@pegaferno4429
5 күн бұрын
12 years and you've helped yet another student. Thanks mate
@llkeeley
4 күн бұрын
Happy to help. Best Wishes.
@llkeeley
11 жыл бұрын
You are most welcome. I am happy I can help students understand this complex physiological process.
@maxvincentplz
10 жыл бұрын
Clear and calmly explained. Thanks Mr. Keeley!
@llkeeley
11 жыл бұрын
You are welcome. I am happy that you found it instructive.
@johngrubbs
12 жыл бұрын
Thanks for putting this up! It will definitely help me with my animal physiology test tomorrow.
@llkeeley
12 жыл бұрын
You are welcome. Thank you for your interest.
@jessicabednark6710
9 жыл бұрын
Nicely done, thank-you!
@arghamariomallick6183
11 жыл бұрын
Thanx a lot 4 ur labour 4 creating this video.it's a great service 2 studnts.thanx 4 enlighting us.all sucess in ur future plans.God bless...
@llkeeley
12 жыл бұрын
You are welcome. Happy to have helped. Hope you did well?
@llkeeley
12 жыл бұрын
Thank you! Always happy to hear the videos are helpful and instructive. LKeeley
@sarahossam6132
8 жыл бұрын
Thank you, it will definitly help me
@llkeeley
12 жыл бұрын
You are welcome. Hope you do well on the test.
@llkeeley
11 жыл бұрын
No, you can link to it or if you want a copy, flash and wmv (for PPT) versions are available for download on my business site.
@PoojaKumari10
8 жыл бұрын
why did I not see it earlier? That came in my exam earlier. You explained it so well.
@dhruvpandey8880
4 жыл бұрын
Sir,but according to the equilibrium, shouldn't the product of the permeable ions' concentration be equal on both sides. How will that happen if the ions are generating a more negative potential inside?
@what_do_you_want898
10 ай бұрын
this was so helpful. thank you!
@llkeeley
10 жыл бұрын
You are most welcome.
@dofor8161
Ай бұрын
Thanks so much ! But didn't understand: Why is chlorine the first ion to migrate?
@anhhai9289
4 жыл бұрын
Thanks to you video, i got better knowlegde on this phenomenom. But i am wondering, as if at the time it is balanced, is side 1 still stay negative related to side 2? I see on side 1 there are x+y K+, y Cl- and y Pr-, so there is no electrical charge, so do side 2. Does this make the voltage gradient between 2 side is zero? Hope to see your reply, i am going to have a test on this =( Thank you very much!
@hanhtranvan3740
3 жыл бұрын
bruh he forgot to rep
@romanmakarov4543
7 жыл бұрын
Could someone explain me why in the last stage, when one potassium ion come back to 2nd solution, the concentration of potassium in 1st solution is steel equal (x+y)? And why finally, when the diffusion in balanced solutions lasts, two ions (K and Cl) stay in 1nd solution, but don't replaced by two ions from there, as it was before?
@llkeeley
7 жыл бұрын
I am not sure of your question? I found with myself and my students that the Gibbs-Donnan equilibrium was one of the more difficult physiological/chemical concepts to comprehend since it involves two simultaneous, dynamic competing and cooperating processes, and we tend to think in terms of simple gradients acting individually. First, do not worry about the actual movements of the few ions shown here, in my limited example. This happens in real life with billions of ions being involved so the movement of a single or several ions is inconsequential in the "big picture" of the cell membrane. (See my last scene with the intact cell.) The important point is that if you have 3 ions: a permeable cation (K+ or Na+), and permeable anion (Cl-) and an impermeable anion (Pr-) you will cause an imbalance in the numbers of permeable cations between the two sides of a semi-permeable membrane and a net charge across the separating membrane. This is because you are dealing not just with diffusion along concentration gradients by the permeable ions, but also the formation of electrical gradients attracting and repelling caused by the impermeable ion. The x + y or x - y formulas are based on the final equilibria. At equilibrium, individual permeable ions are moving continuously back and forth across the membrane according to the temporary, shifting concentration and electrical gradients, but the net overall result is what is calculated. Bear in mind this is explained for a artificial, semi-permeable membrane. The situation with a cell membrane is more complicated since cell membranes have differential permeabilities and ion-selective pumps and channels. If I have missed the point of your question -- I apologize, and maybe another viewer that has more physical chemistry experience can provide a better reply?
@mattball7074
7 жыл бұрын
Potassium leaves in the last stage because there are now 'too many' potassium in side 1 (because it wants to counteract the increased negativity produced by chloride). The potassium naturally wants to spread out (just as what happened to the chloride). I am not totally sure what you are asking but I think the point highlighted here is that the movement of ions is effectively zero. Ions move in a counterproductive way because the directions are always counteracting one another. This would be analogous to a lightbulb. A lightbulb is just a series of flicker. Yet, it occurs so quickly, our visual system cannot distinguish the ON/OFF intervals so it appears to just be constantly on. In this case, the membrane and its ions tend to be consistently stable. Remember equilibrium potential and concentration gradient.
@noorhan4945
10 ай бұрын
Already 12 years, Long way to go.
@xiaozhu7219
2 жыл бұрын
why finally side one has more negative charge distribution at interface , while side two has more positive charge distribution at surface?
@agglyusr
Жыл бұрын
Really good! Thank you!
@llkeeley
Жыл бұрын
You are welcome
@hitokirib2229
6 жыл бұрын
Why is the side with permeable ions positive and non-permeable ions negative?
@llkeeley
6 жыл бұрын
The Nernst equation can only account for those ions that are permeable to the membrane. It explains an unequal distribution of the permeable ions. Impermeable anions are present on only one side, so the overall potential is negative on side 1 vs side 2. In a real cell, there are many more impermeable anions than cations, for example proteins. Also, cell membranes are essentially impermeable to sodium, so most of the sodium ions are outside the cell and the charge on the membrane is basically based on the equilibrium of the K+ ion distribution. This concept of unequal distribution of charge on a semi-permeable membrane with an impermeable anion on one side, is probably one of the hardest to comprehend in physiology since it appears counter-intuitive, but the impermeable anion concentration cannot be taken into account by the calculation and is the cause for the dis-equilibrium and the resulting charge ACROSS the membrane.
@atliakinci
10 жыл бұрын
It will help me in final exam.
@sohasam6969
8 жыл бұрын
but how can ions pass through semi permiable membrane? as only solvent molecules move in osmosis
@llkeeley
8 жыл бұрын
+Dr Dur Muhammad The point of my video (Gibbs-Donnan Equilibrium) is to explain how a synthetic membrane permeable to Na, K and Cl ions establishes an electrical charge when an impermeable ion is present on one side. At equilibrium, you have an unequaldistribution of solutes and electrical charges across the membrane. And in this artificial situation, because of the differential solute concentrations, there is an osmotic differential as well. Therefore, when an impermeable ion is present on one side of a semi-permeable membrane and a solution of ions on the other side, an unequal distribution of ions and an electrical charge will form naturally across the membrane without any additional causative outside influences. This predicts that the charge on a living cell membrane is in part the natural result of the Gibbs-Donnan equilibrium due to the presence of a high concentration of organic molecules in the cytosol relative to the extracellular fluid. However, the point is that the cell has additional effectors such as ion channels and pumps so that the relative distribution of ions across the membrane has regulations and is more complex than only the Gibbs-Donnan equilibrium. In describing osmosis, it is true as you state, that water flows from a dilute solution across a semi-permeable membrane into a concentrated solution if the solute is impermeable to the membrane. Cells are loaded with membrane-impermeable organic molecules relative to extracellular fluid, so water is drawn into the cell to dilute the cytosol and can burst the cell. But, in real life, the extra and intracellular fluids are isotonic so water is not drawn into the cell. Osmotic pressure is a function of the total concentration of solutes in solution and is independent of the nature of the solutes (a colligative property of solutions). Therefore, what extracellular fluid lacks in organic solutes, it makes up with inorganic electrolytes, esp. Na, K and Cl. Ultimately,the osmolarities (total solute concentrations) of the extracellular fluid and the intracellular fluid are identical due to the relative distributions of mainly the Na, K and Cl ions. The extracellular fluid is rich in electrolytes but dilute in organic molecules relative to the intracellular fluid, but between the two, the total solute concentrations even out to be isomolar.
@berasehebi5464
3 жыл бұрын
Thank you very much
@devi.m.s6144
11 жыл бұрын
Thanx a lot for this very well made video.Do u mind if i use this in my ppt.which will be shown to undergraduates in our medical college.Once again thank u.
@Daniel.-.-.
4 жыл бұрын
Thank you!!
@femidaelettil1002
5 жыл бұрын
Thank you
@RidleyE
12 жыл бұрын
thank you
@user-ffrriieennddllyy
2 жыл бұрын
Этот эффект постоянно присутствует? Он непрерывен?
@samacumen
11 жыл бұрын
It seems very confusing: What is the difference b/w electrical and concentration gradients. I think you could explain more in steps. Thank you.
@pragyanprasannipatra6246
3 жыл бұрын
Nice session
@janetrott5505
2 жыл бұрын
I love physics it's so interesting.
@ebervazquez9098
8 жыл бұрын
Thank you for your explanation
@llkeeley
8 жыл бұрын
+Eber Vazquez You are welcome. Happy to help.
@aboudy0532
6 жыл бұрын
thanks
@llkeeley
6 жыл бұрын
You are welcome
@cptenovsky1289
5 жыл бұрын
Thanks
@llkeeley
5 жыл бұрын
You are welcome
@prankulkhataur2931
6 жыл бұрын
Thnq sir
@thomasanderson1416
4 жыл бұрын
What's diffusion gradient
@llkeeley
4 жыл бұрын
High concentration of a chemical on one side of a permeable membrane and lower on the other so the chemical has a concentration gradient to diffuse from high to low.
@thomasanderson1416
4 жыл бұрын
@@llkeeley so diffusion gradient = chemical gradient only or chemical gradient + electrical gradient in a particular direction?
@thomasanderson1416
4 жыл бұрын
@@llkeeley Another Another question about the equilibrium potential, is it one potential for the whole solution or multiple potentials for each molecular type?
@llkeeley
4 жыл бұрын
@@thomasanderson1416 A bit of both. The concentration differential forms a chemical gradient and the unequal distribution causes an electrical gradient between the two sides either + or - depending on the charge of the ion. You can have a concentration gradient for uncharged chemicals so there is no electrical gradient. The magnitude of the electrical gradient for a given ion is calculated by the Nernst equation and based on the differential in concentrations.
@llkeeley
4 жыл бұрын
In response to the second question there is a potential for each ion and an overall potential for the entire solution that is comprised of combining the concentrations into an overall Nernst equation. This is shown in textbooks for the overall charge on a cell membrane. I was demonstrating a simple case for only the single K+ ion. But the overall charge requires both the Nernst eqn. for (K+) and (Cl-) ions, and accounting for their different charges in the final eqn. As i said, this is one of the more difficult physiological concepts to try and imagine since it is a dynamic process involving multiple factors such as membrane permeability and in cases of living cells - differential membrane permeabilities, ion-specific channels and transport proteins. My illustration focuses on simple (nonliving) permeable and semi-permeable membranes.
@user-sg8li4th9t
2 ай бұрын
전남대학교 21학번 다녀감
@hewaahmedmustafa8027
3 ай бұрын
these preprint papers claimed reversing entropy by mixing Raoult's law with osmosis principle and extended Gibbs Donnan Equilibrium . What do you think about this novel approach? Title of the papers: Experimental Demonstration of Energy Harvesting by Maxwell's Demon Device DOI: 10.20944/preprints202403.1698.v1 .... An Autonomous Mechanical Maxwell's Demon DOI: 10.14293/S2199-1006.1.SOR-.PP5S6NK.v1
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