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Old 07-31-2011
surez18's Avatar
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Question Cell transport..

As part of medical reserch medical student has cardiac AP +60 mv first time, +30 mv second time.why its dec on 2nd time?
1. add more Na+ outside cell
2. remove more Na+ outside cell
3.add more k+ inside cell
4.add more k+ outside cell

neeed expl too..

thanks
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Old 07-31-2011
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I am just start reading eletrophysiology.

Action potential is largely due to the influx of Na. When extra celluar Na is reduced, less Na is available for influx and therefore reducing the amplitude of action potential.

This is why we feel weak when we do not have enough salt.
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Old 07-31-2011
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Default 4) its potassium efflux outside from the cell

Quote:
Originally Posted by surez18 View Post
As part of medical reserch medical student has cardiac AP +60 mv first time, +30 mv second time.why its dec on 2nd time?
1. add more Na+ outside cell
2. remove more Na+ outside cell
3.add more k+ inside cell
4.add more k+ outside cell

neeed expl too..

thanks

increase in efflux of potassium,so does it increases potassium outside the cell..i.e phase 3 of the cardiac myocyte action potential..

by the way add,remove u mean to say from intracellular to extracellular or from outside source!!!,since its an experiment question..
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Old 07-31-2011
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Quote:
Originally Posted by drgsarunprasath View Post
increase in efflux of potassium,so does it increases potassium outside the cell..i.e phase 3 of the cardiac myocyte action potential..

by the way add,remove u mean to say from intracellular to extracellular or from outside source!!!,since its an experiment question..
yup u are right thats why patients with hyperkalemia have more incidence of getting arrythmias ...one general rule as said by dr.conrad in his lectures that cardiac membrane potential and RMP's are maintained by K+ ions and potassium abnormalities associated with heart problems while sodium abnormalities are associated with cns problems like cerebral edema etc
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