Membrane Potentials - Part 1 | Circulatory system physiology | NCLEX-RN | Khan Academy

Find out how a cell that is permeable to one ion can become charged (either positive or negative) if there is permeability and a concentration gradient. Rishi is a pediatric infectious disease physician and works at Khan Academy. Created by Rishi Desai.
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[@khanacademymedicine]

Terrific! The cells are pretty amazing aren't they?

[@Holdivar]

This is the most pleasant, least boring video explaining Membrane Potentials that I could find. Thank you.

[@MonkeyDLuffy-xr4fl]

Sorry, but what exactly about membrane potentials could possibly be boring?

[@mehak8827]

Damn . Exactly. I had to go through a lot of videos

[@alissashape5541]

This is awesome! I have an exam in Physiology on this tomorrow. KHAN, you are a lifesaver.

[@chrisjames9262]

Seriously my text books confuse the hell out of me. In 8 minutes I have a full understanding of this. I love this site.

[@emilyshaw7289]

OH you're voice, so wonderful! Thank you for being so excited about teaching, so easy to listen too

[@JEMPHREY]

This is the first time anyone has explained membrane potential properly to me. The anion/cation relationship explained it perfectly. I'll be watching lots more of your videos! Thanks:)

[@melissajoiner8555]

This is so extremely helpful. Thank you so much for posting!

[@ItsTheJackpot]

I'm learning about the heart right now, and then I mean the advanced stuff. You addressed everything in one chapter of my book, but so much clearer. Thank you!

[@imogencampbell7863]

This was fantastic! I finally get it! Thank you :)

[@clairemetcalf6805]

You made it so clear! Thank you.

[@RuthEarle]

Made it really easy to understand with great pace. Thanks so much.

[@rassclartindeairblud5335]

Thanks a lot! I'm so glad you addressed that problem at the end, it was causing me a bit of a headache O;

[@ggsksandika1863]

Thank you, appreciate it a lot

[@527bonbon3]

What amazing sound!❤️

[@jahnavi719]

That was awesome! Thank you.

[@lailingtsang855]

I'm taking the course too!

[@maryhara2053]

Amazing thank you 😊

[@shahwasi5531]

thanks you just solved my query ...... in last minutes of this video

[@biologywithbasira]

You are just amazing, explanation is brilliant 👌thank you soo much ❤️

[@khashayarmastoori1]

Thanks for the great explanation

[@motazaldbass7268]

Thanks a lot it was really helpful

[@occupytosavetheworld]

man you're awesome i swear thank you

[@reardelt]

brilliant video. Btw I love the way you write "e"s.

[@xolanikhumalo9267]

nice vid!

[@fayfa.2524]

Thank u very much for this lecture I do understanding it know

[@sinoyolohele3197]

Thank you very much❤️. Studying for exams

[@ujjwalnadhani9524]

This video saved my biochemistry grade.

[@malithprasanna9480]

Thank you

[@Orangesoda65]

It enters through both leak (always open) channels and the Na/K ATPase pump. There is a slight outflux of K+ due to the resting membrane potential being -70 mV (not -90 mV, K+'s equilibrium potential). So the pump has to make up for this by bringing some back in through active transport.

[@phangvengan1513]

Amazing video, sir!! Really really helpful..... Anyway, you have a sweet voice too xD

[@ajx8571]

excellent

[@LOVELYrandomnessx3]

Hi, I have a question regarding membrane potentials. if a membrane potential goes to 0 mV would any ions be at equilibrium (that is, have no net forces)?

[@hayleelanford5441]

I love your videos!

[@One1Raptor]

Thank you for your reply. I assume that the cells DNA defines the "default" membrane potential?

[@pathatlon]

Search for "Sodium Potassium Pump (ATPase)" from Engineer Clearly. He explains it soooo well!!

[@congratulation46]

Thank you very much for your amazing video. May I ask what kind of app you have used for teaching?

[@wehatedisneystars]

Thanks dad

[@One1Raptor]

Very nice video. Need one point to the puzzle to understand 100%. The K ion enter the cell again due to the membranpotential. Does it enter through the ion chanels or through the Na/k pump? Hope you have time to clear this out!

[@johnconnor2820]

Very nice explanations. Just wondering what program are you using to draw your tutorial? thanks

[@MrIeatwabbits]

These may be some other important [molecule] to possibly keep out for. Hope this helps Na+ = 10x OUT K+ = 30x IN Ca2+ = 10,000x OUT H+ = 2x IN Cl- = 10x OUT

[@Ra-rg1vk]

I understood it like married men inside the 'cell' leaving their wives (anions) and running out of the cell causing lot of negativity inside the cell. Men on the outside see these abandoned wives and move inside the cell thus helping them to lower the negativity and the men then reach equilibrium

[@Orangesoda65]

K+ leaves because it has an equilibrium potential of -90 mV (if it was the only permeable ion in a cell, it would leave the cell due to its high concentration side and leave enough of the anions it was paired with so that the cell would have a potential of -90 mV). The normal human cell has a potential of -70 mV, notice that's more positive than potassium's equilibrium potential, so there is a small outflux of potassium as it tries to reach its own ion potential by leaving.

[@whodooable]

Is this membrane potential considered particularly strong if it breaks ionic bonds between K's and anions?

[@winstonburbank1946]

i wish i was dead

[@rassclartindeairblud5335]

what do you mean?

[@hamedhosseini4938]

He cannot understand this topic, he wishes he was dead so he didn't suffer through understanding this topic I believe. rip

[@cocochanel3436]

me too

[@shayona1460]

hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh @@hamedhosseini4938

[@MEMO2011O]

Me too

[@aches6652]

it s helps thankss but the concentration of Cl- cytoplasm is very low like 50 mM so the k+ can't be coupled by it ... the green molecules with negative charge can be pr , aa , HCO3- ... i'm i wrong ?

[@prateekchauhan1187]

Does a negative membrane potential imply a negatively charged cell

[@225rip]

Can this be measured with a meter, where is ground or reference point?

[@Holyacrobat1]

Ok so I am a little confused. I understand the concentration gradient, and the membrane potential. what I don't get is how the membrane potential would be negative if "the same amount of potassium is moving out, thats moving back in". If the amount moving in is equal to the amount moving out, wouldn't the voltage be zero, or whatever it was to start out with. I feel like there would me more potassium that left, than came back in, to make it negative. any explanation would be very helpful. thank you in advanced.

[@SanamLimbu]

It becomes negative once the Potassium exits the cell, as a result the anions are left alone hence making the cell negative.

[@melaniek.3602]

Helped a lot. I still want to understand the graphs with the concentration gradient of K+ and the membrane potential a little more. I think as time goes on the rate of K+ going out the membrane increases, but eventually reaches a certain point where the rate is constant, and the negative charge on the inside will also be constant. But I don't understand how would the net movement of K+ be equal from then on if the charge inside would still be negative? I'm not really sure what happens with net movement--if it's constant, negative, positive w.e. I would like some explanation on this. Also do the K+ ions want to have equal concentrations on both sides? Thanks.

[@Abhishehkmuchandi]

The K+ start moving out, into the ECF causing negative charge accumalation in the cell.The electric gradient generated by accumalation of this negative charge is not enough to pull back the K+ ions from ECF into the cell. The negative charge in the cell reaches such a level that it builds a potential gradient strong enough to pull K+ from ECF into the cell. At this point there is already loss of certain amount of k+. Once the k+ start entering the cell(there is simultaneous efflux of k+ from the cell,but the number of k+ entering the cell is greater momentarily) the potential gradient comes down and when it reaches 92 mVolt the number of k+ entering and leaving the cell becomes equal.Equilibrium is attained at this point but there is already a gradient of 92 mVolt that cannot be overcome.

[@Dr_hrx]

What happen to RMP if intracellular potassium concentration reduce to the value of extracellular potassium concentration?

[@mehak8827]

Damn your voice . Thanks for explaining :)

[@marecare21]

You save lifes, you know that right?

[@ananditaralhan5780]

Pottashium can not move out of the cell because cell membrane is impermeable to K and negative proteins so as to cause the movement of K there is voltage gated channels which are activated only when stimulus is given not applicable here because we're discussing resting membrane potential- i.e the potential in absence of stimulus...the negative charge inside the cell is because of net movement of three sodium outside while only 2 K move inside thus relative negative charge develops inside due to the Na-K pump which is the only pump responsible for maintaining the RMP also it is an active pump that uses ATP as the movement of ions is AGAINST concentration gradient

[@MinuteMindsFun]

I put every Bozeman video at 2x speed to learn twice as fast :)

[@m.t1446]

Same 😂

[@cconn4321]

great. how do i get on your developing team? pre-med pursuing a degree in biochemistry and passion for a paleolithic lifestyle

[@gratefuldev23]

I don't know if this has been pointed out, but there is an error at ~7:55 where you say, "“so about ten to the twenty moles, right?” Not right. It is 10^20 ions. Other than that though, great video!

[@conniecarty5214]

Thank you for you amazing videos. I am also a teacher. What format/program are you using for these videos? Connie Does anyone else know?

[@LavKarri]

it looks like MS PAINT. But I dont' know for sure.

[@boazomido2373]

Is this what nurses go through? Nurses are awesome!

[@AnyTechReview]

are you a nurse?

[@boazomido2373]

A medical student

[@manoruss24]

Very nice... Is equilibrium potential is Resting membrane potential? Thanks

[@Dagreton]

Mano jaba singh Russaliah Yes, exactly :)

[@IPIhantom]

+Mano jaba singh Russaliah equilibrim potential is not RMP.... RMP is at about 70mV while equilibrium potential is at 90mV. The difference of charges is due to sodium moving along its concentration gradient and "leaking" into the cell. Potassium would not leak into the cell because that would cause it to move against its chemical gradient

[@manoruss24]

thanks

[@nsaifi80]

yes

[@klaymonkey9073]

i'm confused. what's the difference between membrane potential and action potential?

[@jessicablack2306]

I love you.

[@j12torts]

I love you too lol :)

[@franklincarpenter5431]

I love you too, as well

[@janaenae1338]

What do you call A person who inhaled smoke and suddenly has tons of positive ions emmiting from their body and also has genes that carry hypokalemia

[@zabcdefghijklmnopqrstuvwxy114]

K+ come inside of cell due to electrical gradient but by which channel or by using ATP?

[@pavankumaraakash]

Voltage gated K+ channel

[@CrankyRayy]

I just don't get how they leave behind anions? I thought the element *itself* was negatively charged.. Anyone care to explain the "detachment" of these anions in more detail to me?

[@judojustim]

why does the k even leave in the first place.? or why does k just change its mind and turn around?

[@MynamedidntFitDonkey]

at 4:35 he drew potassium entering the cell through the plasma membrane,isnt that wrong?I thought ions can only pass through their specific channels.

[@WardVH]

you should know that, Mr. Antoine Lavoisier :p

[@nsaifi80]

from where 6.02×10 power 23 comes from? can anyone explain please

[@gratefuldev23]

Avogadro's number, Number of items (molecules, atoms) in a mole.

[@judojustim]

why "doesnt" k change its mind

[@maharaziq8689]

Why Sodium cannot leak throyh K channels in spite of the fact that it is a cation ?

[@biolearn8464]

I thought K+ resting membrane potential was -70mV??

[@hildatinotendachieza2620]

Yes, resting membrane potential of K+ is - 70mV but the equilibrium potential of K+ is - 90mV

[@stephenprice3357]

I thought K moved in?

[@summertime2433]

Shouldn't this video be titled potassium equilibrium? You also have sodium equilibrium of +60mV and the combined effect of both Na+ and K+ creates a resting potential of -70mV.

[@ayxansafarov1859]

Omg

[@sanjeevpenaganti7853]

Please speak clearly

[@fahadksa1993]

Could you please teach us instead of these old expired lecturers at Jordanian university of since and technology... thanx a lot

[@anhquaan]

how many of you here are taking courses at coursera.org like me?

[@snowqueen19900]

ارتقي الله يهديك هو وشوا هو هندي الاصل اساسا ههههه ابحث عنه وتعرف .