Ion Manipulation

by Thad Wilson, PhD

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    Now, we have membrane potential down, what do we know that’s most important? Potassium, potassium, potassium, potassium. Potassium is very important for resting membrane potential. Let’s manipulate it a little bit because you won’t always have the same potassium concentrations, right? There are times when you have high potassium, there’s times when you have low potassium. How does that change membrane potential? So if we have our cell here at minus 70, it’s normally leaking out some potassium. That’s very normal, sodium-potassium pump rotates some of it back in. If you are in a hypokalemic state, meaning there’s now low potassium in the extracellular space, so that’s the interstitial fluid and the plasma, have low potassium. How does this change membrane potential? More potassium will want to leave the cell because the concentration gradient is higher, that hyper polarizes the cell and makes it more negative. You can see the more negative here within oscilloscope tracing. So what you’re doing is moving more potassium out of the cell. It’s getting closer to this minus 90 value. If you actually measure it, you can get all the way to minus 90 in a hypokalemic environment. What if you start with a membrane potential that’s normally about minus 70, you have the normal potassium leak out of the cell, and now, instead of hypokalemia, we’re in hyperkalemia. We have a high amount of potassium outside the cell. This could be for many different reasons. It could be because other cells in the body are pushing its potassium out of the cell, which sometimes happens during an acidosis. It could also be that you have dietarily intaked more potassium than you need. So if you’re in a hyperkalemic environment, membrane potential rises. It becomes less negative. There is less of a driving force...

    About the Lecture

    The lecture Ion Manipulation by Thad Wilson, PhD is from the course Membrane Physiology.

    Included Quiz Questions

    1. Depolarizes
    2. Increases membrane potential
    3. Hyperpolarizes
    4. Makes the membrane potential more negative
    5. Causes outflow of potassium to compensate for excess sodium in the ICF
    1. -70mV
    2. -90mV
    3. -60mV
    4. -100mV
    5. -50mV
    1. It hyperpolarizes
    2. It depolarizes
    3. It decreases membrane potential
    4. It makes the membrane potential more positive
    5. Causes inflow of sodium to compensate for the loss of potassium into the ECF
    1. Potassium
    2. Chloride
    3. Sodium
    4. Calcium
    5. HCO3-
    1. Depolarizes
    2. Hyperpolarizes
    3. Becomes more negative
    4. Goes down on the oscilloscope
    5. Remains unchanged
    1. The opening of other ion channels
    2. The loss of membrane proteins
    3. The addition of membrane proteins
    4. The closing of potassium channels
    5. The addition of more potassium channels
    1. …inward…depolarized
    2. …outward…hyperpolarized
    3. …inward…hyperpolarized
    4. …outward…depolarized
    5. …outward…isopolarized

    Author of lecture Ion Manipulation

     Thad Wilson, PhD

    Thad Wilson, PhD

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    very clear and eazy to understand reccomended to whoever needs to study phisiology
    By RACHEL B. on 04. February 2017 for Ion Manipulation

    very clear and eazy to understand reccomended to whoever needs to study phisiology