Final answer:
Receptors experience graded potentials, which are changes in membrane potential that vary depending on the stimulus size and can lead to action potentials if the threshold is reached.
Step-by-step explanation:
The type of change in polarity in receptors are graded potentials which can be either depolarizations or hyperpolarizations.
A graded potential is a change in the membrane potential that varies in size, depending on the size of the stimulus that elicits it. This localized change in potential can occur in various types of cells, including sensory neurons and other sensory receptor cells. When a graded potential reaches a sufficient level, it can trigger an action potential, which is an all-or-nothing electrical signal that travels down a neuron's axon. Graded potentials are crucial in determining whether an action potential will occur and are associated with the dendrites of a neuron.
The membrane potential can shift positively (depolarization) or negatively (hyperpolarization) based on specific stimuli, such as temperature changes or chemical interactions, which activate specific ion channels in the cell membrane. If these graded potentials summate to reach a threshold, an action potential is then generated and propagated along the axon.