Final answer:
The process where stimulus energy is transformed into a change in membrane potential is known as transduction. The specific type of energy a sensory receptor can detect is termed its adequate stimulus, and the least amount of stimulus required to elicit a perceptible response from the receptor is referred to as the threshold.
Step-by-step explanation:
The conversion of stimulus energy into a change in membrane potential is called transduction. The form of energy to which a receptor responds is called its adequate stimulus. The minimum stimulus required to activate a receptor and produce a significant response is known as the threshold. Sensory receptors undergo transduction when they convert various forms of environmental stimuli, such as mechanical pressure, chemicals, or temperature, into electrical signals that are understood by the nervous system. The process begins when the sensory receptor is activated by an adequate stimulus; these receptors are configured to detect specific types of energy. For example, thermoreceptors respond to changes in temperature.
Receptor cells can generate different responses depending on the strength of the stimulus, known as graded potentials. If a graded potential reaches a certain level, known as the threshold, an action potential will be triggered, allowing the signal to travel along the neuron to the central nervous system for processing. The adequate stimulus for receptors can vary, with some receptors capable of detecting light, sound, temperature, or chemical changes.