What does excitability refer to in physiological terms?

In physiological terms, excitability refers to the ability of a cell, such as a muscle or nerve cell, to respond to stimuli. This characteristic enables these cells to generate electrical impulses or action potentials when they receive an appropriate signal. For instance, in muscle cells, this responsiveness allows for contractions in reaction to signals from the nervous system, while in neurons, it allows for the transmission of signals along the nerve pathways.

The concept of excitability is essential for understanding how the body reacts to external stimuli and for the coordination of bodily movements. If a cell is highly excitable, it will respond quickly and effectively to stimuli, while lower excitability may lead to slower or less effective responses. Thus, the definition directly aligns with option B, making it the correct choice in this context. Additionally, this responsiveness is a fundamental aspect of muscle and nerve function, underlining its importance in physiology.