Characterization of the resting potential of cardiomyocytes

In the case of ventricular muscle, its resting potential.

It is about -90mV, and the production principle has two points: 1) the concentration of K+ in the resting state is higher than that in the extracellular; 2) Cell membranes in the resting state.

It has high permeability to K+, so K+ forms a negative and positive polarization state from the inside to the outside of the cell.

Action potential. The whole process is divided into 5 periods, namely the 0 stage of the depolarization process and the repolarization stage.

1) Phase 0 (depolarization period): -90-+30mV, constituting the rising branch of the action potential, which lasts only 1-2ms, caused by the rapid and massive influx of Na+, this potential is also called the fast response potential, and the cardiomyocyte has this potential.

These are called fast-reacting cells.

2) Phase 1 (early stage of rapid repolarization): +30 0mV, 10ms, caused by k+ efflux, phase 0 and phase 1 constitute the front potential.

3) Phase 2 (plateau period.

The repolarization is slow, stagnant below 0mV, plateau-shaped, composed of K+ outflow and Ca2+ slow inflow, 100ms-150ms.

4) Stage 3 (late stage of slow repolarization): 0mV 90mV, caused by K+ rapid outflow, 100ms-150ms.

5) Stage 4 (resting phase): -90mV. Active transport, Na+ and Ca2+ pumped out, K+ pumped in, returned to resting state.

1.First of all, there are different types of cardiomyocytes, do you mean ventricular muscle, atrial muscle?

This is because autonomic cells, such as sinus node P cells, do not have a resting potential, but can only be said to have a maximum repolarization potential. ）

2.You ask "what is the resting potential of a cell in general," you ask

Because the resting potential of different cells is different, there is no general, for example, nerve cells are about -70mV, skeletal muscle cells are about -90mV, red blood cells are about -10mV, and so on, the RP of different cells is different, but the RP is negative.

3.You ask, "What is the action potential of cardiomyocytes?" ”

Because the action potential is not like the resting potential which is a constant value, it cannot be said which cell has what the action potential is.

electrochemical equilibrium potential.

The electrochemical level of the balance potential.

Electrochemical equilibrium of electro-hydraulic limb position.

and k+ equilibrium late potential.

and k+.

Correct answer: c

Answer]: The formation of the resting potential of ventricular myocytes is mainly due to the activation of the K+ channel on the cell membrane, resulting in the rapid outflow of a large amount of balanced K+. Ventricular myocyte action potential repolarization stage 1 is characterized by rapid repolarization of intramembranous potential from +30mV to 0mV, mainly formed by K+ transient efflux.

Answer]: The difference in ion concentration between the inside and outside of the myocardial cell membrane causes a potential difference between the inside and outside of the membrane. Physiologically, the extramembrane potential is determined to be zero potential, and when the intramembrane potential is lower than the extramembrane potential, it is called negative and good dismantling, and vice versa.

For cardiomyocytes, the membrane potential at rest is called the resting potential or membrane potential (-90mV).

Answer]: a, b, d

In the resting state, the ventricular myocyte membrane has great permeability to K+ and also has a certain permeability to Na+, so K+ diffuses from the membrane to the outside of the membrane along the concentration gradient to form the K+ equilibrium potential, and a small amount of Na+ influx forms the Na+ equilibrium potential. In addition, the activity of the supramembranous electrogenic Na+-K+ pump can also affect the value of the resting potential of the ventricular myocyte reed wheel. Thus, the resting potential of ventricular myocytes is a combination of K+ equilibrium potential, Na+ equilibrium potential, and electrobiotic destructive Na+-K+ pump activity.

Answer]: The main feature of the action electrodulum of ventricular myocytes is that the repolarization process is complex and lasts for a long time, and the action potential pattern of the repolarization phase 2 is compared with that of the finger chain and the plateau.