contestada

What is the correct sequence of events along an axon that follows a membrane reaching threshold potential? 1. The membrane depolarizes. 2. Sodium channels open and sodium ions diffuse inward. 3. The membrane repolarizes. 4. Potassium channels open and potassium ions diffuse outward. Group of answer choices

Respuesta :

shakan
2 1 4 3 i hope it helps
marianaegarciaperedo

When a stimulus exceeds a threshold level, sodium channels open depolarizing the axon. Gradually, Potassium channels open too, leading to the axon repolarization. The correct order of events is 2, 1, 4, 3.

-----------------------------------------------

  • Neurons transmit nerve impulses. The transmission depends on the unequal distribution of ions in the interior and the exterior of the cell.

  • The cell interior has many negative ions –anions- and k+ ions that cannot get out of the cell, while the extracellular space has many Na+ and Cl- ions.  

  • The charge difference between the interior and the cell exterior is the resting potential difference, representing a non-exited state.  

  • The neuron stimulation provokes many changes in channel proteins, letting the ions move through the membrane. This interchange produces an alteration of the resting-potential difference.

  • When the axon is stimulated the membrane depolarizes.

  • When the stimulus exceeds a threshold level, several sodium channels open simultaneously letting the ion in, and the action potential occurs, responsible for the nerve impulse transmission.

  • Gradually, the Na+ channels get closed, K+ channels open.

  • Ions traffic consists of the pass of sodium to the interior of the cell and potassium to the exterior.

  • K+ follows a concentration gradient, while Na+ follows an electrochemical gradient.  

  • When the electrical stimulus is applied to the membrane of the axon it produces depolarization by activating the sodium voltage-dependent channels all along the axon.

  • Depolarization propagates to inactivated regions adjacent to the membrane opening more sodium channels.  

According to this information, the correct order of events is,

2. Sodium channels open and sodium ions diffuse inward.

1. The membrane depolarizes.

4. Potassium channels open and potassium ions diffuse outward.

3. The membrane repolarizes.

----------------------------------

Related link: https://brainly.com/question/15133336?referrer=searchResults

                     https://brainly.com/question/13669973?referrer=searchResults

Otras preguntas