What term describes the action of one agent on another that evokes activity in the receiving structure?

What term describes the action of one agent on another that evokes activity in the receiving structure?

• A. Stimulus
• B. Threshold
• C. Sub-threshold
• D. Response

Answer: (A)

A stimulus is the input that initiates activity in a receiving structure. In biology and physiology, it’s anything that can be detected by receptors and triggers a response. The stimulus can come in many forms—mechanical, chemical, thermal, electrical, and so on—and it’s the trigger that starts the chain of events inside the receptor or neuron. If the stimulus is strong enough to push the system past its required level, it can lead to a response, such as generating an action potential. The concept of threshold is about the minimum stimulus needed to produce that response: a stimulus below this level is sub-threshold and won’t elicit a reaction. The actual reaction or output is the response, which occurs after the stimulus is detected and processed. So the term for the triggering input that evokes activity in the receiving structure is the stimulus.

A stimulus is the input that initiates activity in a receiving structure. In biology and physiology, it’s anything that can be detected by receptors and triggers a response. The stimulus can come in many forms—mechanical, chemical, thermal, electrical, and so on—and it’s the trigger that starts the chain of events inside the receptor or neuron. If the stimulus is strong enough to push the system past its required level, it can lead to a response, such as generating an action potential. The concept of threshold is about the minimum stimulus needed to produce that response: a stimulus below this level is sub-threshold and won’t elicit a reaction. The actual reaction or output is the response, which occurs after the stimulus is detected and processed. So the term for the triggering input that evokes activity in the receiving structure is the stimulus.