Answer :
The action potential created by the sinoatrial (SA) node is not the result of ions leaking in and out. Instead, it is a result of the sequential opening and closing of ion channels. During the action potential of the SA node, the cell membrane undergoes depolarization, followed by repolarization.
The process involves the movement of different ions across the cell membrane. Here is a step-by-step explanation:
1. Resting State: In the resting state, the SA node cell has a more negative charge inside compared to the outside. This is maintained by the Na+/K+ pump, which pumps sodium ions out and potassium ions in, against their concentration gradients.
2. Depolarization: The action potential starts when the membrane potential becomes more positive due to the opening of voltage-gated calcium channels. Calcium ions (Ca2+) flow into the cell, causing depolarization.
3. Repolarization: Once the membrane potential reaches a certain threshold, voltage-gated potassium channels open, allowing potassium ions (K+) to flow out of the cell. This movement of potassium ions leads to repolarization, restoring the negative charge inside the cell.
4. Resting State: After repolarization, the sodium-potassium pump actively transports sodium ions (Na+) out of the cell and potassium ions back into the cell, returning the membrane potential to its resting state.
In summary, the action potential of the SA node is not a result of ions leaking in and out. Instead, it is a carefully orchestrated process involving the sequential opening and closing of specific ion channels. Sodium ions (Na+) do not leak inside, and chloride ions (Cl-) are not involved in this specific process.
To know more about membrane visit-
https://brainly.com/question/28592241
#SPJ11
