You are sitting on a sunny Florida beach experiencing the sensation of warmth.

Question

Describe the anatomical structures and physiological events that allow you to perceive the warmth of the sun.

Answer 1

An ideal answer should be the thermoreceptors, which are distributed throughout the skin, must be present to sense the thermal stimuli. The warmth from the sun stimulates the warm thermoreceptors to become activated by warming the receptive field of thermoreceptors and stimulating the production of graded potentials. When the graded potentials reach the threshold, they trigger nerve impulses in the themoreceptor, which serves as a first-order neuron that transmits the information to the CNS where a second-order neuron conducts impulses via neurons of the spinothalamic tract to the thalamus. From the thalamus, third-order neurons conduct impulses to the primary somatosensory area of the cerebral cortex where the impulses are perceived as a feeling of warmth.