Nerve Axons ( BIOELECTRICITY, ELECTROCHEMISTRY) Question Assume a nerve cell is

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Nerve Axons (BIOELECTRICITY, ELECTROCHEMISTRY) Question
Assume a nerve cell is a cylinder L = 1 cm long and R = 0.01 mm in radius. Thinking of it as a parallel plate capacitor, we know there will be a positive charge Q on the outer surface and a negative charge Q on the inner surface. In addition there will be electrically neutral solutions inside and outside including all types of ions. Use the data in the table in Section 16.2 for the estimates below.
(a) Estimate the number of Na+ ions in the solution inside the nerve cell.
(b) Assuming the positive charge Q on the outer surface is all Na+ ions, estimate how many Na+ there are on the surface.
(c) If the capacitor were to discharge electrically, these positive ions would come inside the cell. How much would the interior concentration of Na+ be affected? That is, how does the number in (b) compare with the number in (a)?
(d) Suppose twice as many Na+ ions came in, so that the capacitor was now charged in the opposite sense, as happens briefly in the axon potential. Would this be enough ions to change the interior sodium concentration appreciably? | [ion, (mM) | [ion], (mW) | V (mV) | V,Nernst (mW) F (meV) -142.4 ion 12 80 -76 -76 -76 66.4 80.1 -76.0 144 Cl- 120

Explanation / Answer

a)The number of Na+ ions in the solution inside the nerve cell is 12 b)The number of Na+ ions in the solution outside the nerve cell is 144. C) When the cell is discharged electrically the postive ions would come inside the cell the concentration gradient of sodiun ions tend to drive inside the negatively charged cell, the number in inside the cell will slightly increase. d)no   

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