 thumb|illustration of free nerve endings a free nerve ending (fne) is an unspecialized, afferent nerve ending, meaning it brings information from the body's periphery toward the brain. they function as cutaneous receptors and are essentially used by vertebrates to detect pain. ==structure== free nerve endings are unencapsulated and have no complex sensory structures. they are the most common type of nerve ending, and are most frequently found in the skin. they mostly resemble the fine roots of a plant. they penetrate the epidermis and end in the stratum granulosum. fne infiltrate the middle layers of the epidermis and surround hair follicles. ==types== free nerve ending have different rate of adaptation, stimulus modalities and fiber types. ===rate of adaption=== different types of fne can be rapidly adapting, intermediate adapting, or slowly adapting. a delta type ii fibers are fast-adapting while a delta type i and c fibers are slowly adapting. ===modality=== free nerve endings can detect temperature, mechanical stimuli (touch, pressure, stretch) or pain (nociception). thus, different free nerve endings work as thermoreceptors, cutaneous mechanoreceptors and nociceptors. in other words, they express polymodality. ===fiber types===  the majority of aÎ´ (a delta) fibers (group iii) and c (group iv) fibers end as free nerve endings. == references == == external links == *  *  *nociception: transduction. from the university of utah. * {{cite journal | author = hada r | title = [difference in responses of free nerve endings and ruffini-type endings innervating the cat mandibular periosteum to square wave pressure stimuli, ramp mechanical stimuli and triangular vibrations] |
Somatic_sensory_system