physiological resting potential

Physiology Cell Electrical Activity Resting Potential, some details, you can read it if necessary

Edited at 2020-09-23 07:52:08

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physiological resting potential

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Outline

central theme

resting potential

A. Measurement and concept of resting potential

A.1. Potential difference between negative inside and positive outside

There is zero potential outside the cell. The greater the negative value inside the cell, the greater the resting potential.

A.2. Polarization: At rest, both sides of the cell membrane are in a stable state of positive on the outside and negative on the inside.

A.3. Hyperpolarization: The process or state in which the resting potential increases and the polarization state of the membrane is enhanced is called hyperpolarization (such as -70~-90)

A.4. Depolarization: the process or state of reducing the resting potential (-70~-50)

A.5. Reverse polarization: The potential within the membrane becomes positive and the polarity on both sides of the membrane is reversed.

A.6. Repolarization: The process by which the cell membrane returns to its resting potential after depolarization.

B. The generation mechanism of resting potential

The basic cause is the transport of charged ions across membranes

B.1. The concentration difference and equilibrium potential of ions on both sides of the cell membrane

B.1.1. Direct power, the concentration difference is mainly formed and maintained by the ion pump (sodium pump)

B.1.2. Electrochemical driving force of ions: transmembrane electric field and ion concentration difference, the algebraic sum of these two driving forces

B.1.3. The transmembrane potential when the electrochemical driving force is zero and the static diffusion of ions is zero is called the equilibrium potential.

B.2. The relative permeability of the cell membrane to ions at rest

B.2.1. The cell membrane is only permeable to one kind of ion in the resting state, and the resting potential is equal to the equilibrium potential.

B.2.2. It is permeable to a variety of ions at the same time. The size of the resting potential depends on the relative permeability of the cell membrane to these ions and the concentration difference of these ions on both sides of the membrane.

B.2.3. The higher the permeability of the membrane to a certain ion, the greater the impact of the diffusion of the ion on the resting potential, and the closer it is to the equilibrium potential.

B.2.4. The measured resting potential is slightly smaller than the equilibrium potential of potassium ions.

B.2.4.1. At rest, the membrane also has a certain permeability to sodium ions, which can offset

C. electrogenesis of sodium pump

C.1. Every time an ATP is broken down, three sodium ions go out and two sodium ions come in.

C.1.1. It is equivalent to a net positive charge moving out of the membrane, and the potential inside the membrane becomes negative.

D. Main factors affecting resting potential

D.1. Extracellular potassium ion concentration

D.1.1. As the concentration increases, the equilibrium potential decreases and the resting potential decreases.

D.1.2. Hyperkalemia strongly inhibits cardiac excitation

D.2. The relative permeability of the membrane to potassium and sodium ions

D.2.1. Increased potassium ion permeability and resting potential

D.2.2. Increased sodium ion permeability and decreased resting potential

D.3. sodium pump activity level

D.3.1. Sodium pump enhancement, electrogeneration enhancement, hyperpolarization

D.3.2. Sodium pump inhibition, resting potential decreases