After application of a stimulus a potential change has occurred in the neuronal membrane but there is no opening of gated ion channels. That change in membrane potential is called as
**Question:** After application of a stimulus, a potential change has occurred in the neuronal membrane but there is no opening of gated ion channels. That change in membrane potential is called as:
A. Depolarization
B. Hyperpolarization
C. Depolarization with no change in membrane potential
D. No change in membrane potential
**Correct Answer:** **B. Hyperpolarization**
**Core Concept:** In neurons, membrane potential is determined by the balance of ionic currents passing through the ion channels, such as voltage-gated and ligand-gated channels. When a stimulus is applied, it leads to a change in the membrane potential due to alterations in the ion flow across the membrane.
**Why the Correct Answer is Right:** Hyperpolarization occurs when there is an increase in the leak current (mainly carried by K+ ions) or a decrease in the inward current (e.g., Na+ and/or Ca2+), leading to a decrease in the membrane potential. In this case, there is no opening of gated ion channels, so the membrane potential remains relatively stable or decreases slightly.
**Why Each Wrong Option is Incorrect:**
A. Depolarization: This term refers to a decrease in membrane potential, which would contradict the given information about no change in membrane potential.
C. Depolarization with no change in membrane potential: This option is incorrect because it contradicts the statement that there is no change in membrane potential.
D. No change in membrane potential: Similar to option C, this choice contradicts the information provided about the potential change in the neuronal membrane.
**Why the Correct Answer is Right:** In the given scenario, there is no opening of gated ion channels, which results in a minimal change or decrease in the membrane potential, leading to hyperpolarization. This process is crucial for neuronal function as it contributes to the resting membrane potential and helps in maintaining the membrane potential during neuronal activity.
**Clinical Pearls:** Understanding membrane potential changes is essential in understanding neuronal excitability and signal transmission. These changes help in regulating various physiological processes, such as neuronal resting membrane potential, action potential initiation, and propagation.
In summary, hyperpolarization occurs when there is no opening of gated ion channels in response to a stimulus. This process helps maintain the membrane potential during neuronal activity, contributing to the resting membrane potential and signal transmission.