Final answer:
Free nerve endings consist of sensory receptors in the skin that are sensitive to painful stimuli, hot and cold temperatures, and light touch.
Step-by-step explanation:
Free nerve endings are the types of sensory receptors that consist of free nerve endings. These nerve endings are the most common nerve endings in the skin and are sensitive to painful stimuli, hot and cold temperatures, and light touch. They are unencapsulated dendrites of sensory neurons and are slow to adjust to stimuli, making them less sensitive to abrupt changes in stimulation. Examples of other types of sensory receptors include encapsulated receptors such as Meissner's corpuscles, Pacinian corpuscles, and Ruffini endings, each with their own specific functions and sensitivities.
The types of sensory receptors that consist of free nerve endings are Nociceptors, Cold receptors, and Warm receptors. These receptors are sensitive to various stimuli, including painful (nociception), cold, and warm temperature changes. On the other hand, Lamellar (Pacinian) corpuscles are encapsulated and rapidly adapting receptors that respond to transient pressure and high-frequency vibration, thus they are not free nerve endings.