Human trigeminal nerve

Odors are perceived via the olfactory system, which is composed of two organs in the nose the olfactory epithelium, a very small area in the nasal system, and the trigeminal nerve endings, which are much more widely distributed in the nasal cavity (11). The olfactory epithelium is extremely sensitive, and humans often sniff to bring more odorant in contact with this area. The trigeminal nerves initiate protective reflexes, such as sneezing or interruption of irrhalation, with exposure to noxious odorants. 

Several investigations of volatile organic compounds (VOC) have been reported. Controlled human chamber exposures to a VOC mixture (25 mg nr3) in healthy volunteers revealed that symptom and irritation intensity was unrelated to detection of aversive odour and more likely related to stimulation of trigeminal nerve receptors (Hudnell et al., 1992). Moreover, similar VOC exposures evoked... 

Typical ocular symptoms associated with exposure to OC aerosol exposure include lacrimation, conjunctival inflammation, redness, severe burning pain, swelling, and blepharospasm. The application of capsaicin to the eye causes neurogenic inflammation and unresponsiveness to chemical and mechanical stimuli. Topical application of capsaicin eliminates the blink reflex for up to 5 days following dosing. Systemic administration of capsaicin is associated with trigeminal nerve fiber degeneration in the cornea. In humans, exposure to OC can cause loss of the blink reflex. 

For example, the trigeminal nerve response lagged markedly behind that of the olfactory nerve. Such peripheral neural data raised the question of whether reaction time to pungency would fall markedly behind reaction time to odor in human subjects. As Figure 4 reveals, it did. Because olfactory and trigeminal... 

Trigeminal chemoreception mediates the perception of chemical pain, as well as thermal, tactile, and proprioceptive cues (Green et al. 1990). This review is limited to the discussion of chemical pain, the kind of stimulation that humans describe as burning, itching, or tingling (Rozin et al. 1982). Trigeminal nociceptors are free nerve endings that can be found in the mouth and nose, as well as... 

---