MEDICAL PHYSIOLOGY

PHYSIOLOGY

CENTRAL NERVOUS SYSTEM

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the normal resting potential of a neuron cell membrane?
A
+40mV
B
-30mV
C
+55mV
D
-70mV
Explanation: 

Detailed explanation-1: -The value of the resting membrane potential varies from cell to cell, and ranges from about-20 mV to-100 mV. For example, in a typical neuron, its value is-70 mV.

Detailed explanation-2: -The resting membrane potential of a neuron is about-70 mV (mV=millivolt)-this means that the inside of the neuron is 70 mV less than the outside. At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.

Detailed explanation-3: -A neuron at rest is negatively charged: the inside of a cell is approximately 70 millivolts more negative than the outside (−70 mV, note that this number varies by neuron type and by species).

Detailed explanation-4: -The relative excess of positive charges outside and negative charges inside the membrane of a nerve cell at rest is maintained because the lipid bilayer acts as a barrier to the diffusion of ions, and give rise to an electrical potential difference, which ranges from about 60 to 70 mV.

Detailed explanation-5: -In humans this is said to be around-70 mV. This means that the inside of the cell is negatively charged in comparison to the outside. Resting membrane potentials are maintained by two different types of ion channels: the sodium-potassium pump and the sodium and potassium leak channels.

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