The gradient of activity produced along the olfactory mucosa by odorant stimulation was measured by the ratio (the LB/MB ratio) of the summated neural discharges recorded from two branches of the olfactory nerve, a lateral branch (LB) supplying a mucosal region near the internal naris and a medial branch (MB) supplying a region near the external naris. Twenty-four frogs "sniffed" sixteen differ...

While the physiology, histology and stem cell biology of smell are active fields of contemporary research, smell is probably the sense that physicians knew the least about prior to the 20th century. Joseph-Hippolyte Cloquet (1787–1840) was an anatomist who, in 1815, defended a singular doctoral thesis—On odours, the sense of olfaction and the olfactory organs—then went on to publish, in 1821, t...

While the physiology, histology and stem cell biology of smell are active fields of contemporary research, smell is probably the sense that physicians knew the least about prior to the 20th century. Joseph-Hippolyte Cloquet (1787–1840) was an anatomist who, in 1815, defended a singular doctoral thesis—On odours, the sense of olfaction and the olfactory organs—then went on to publish, in 1821, t...

Until recently, olfactory dysfunction was an unknown feature of narcolepsy. Orexin A, also called hypocretin-1, is abnormally decreased or undetectable in the cerebrospinal fluid of narcoleptic patients with cataplexies. As hypothalamic orexin-containing neurons project throughout the entire olfactory pathway, from the olfactory mucosa to the olfactory cortex, disturbed orexinergic transmission...

The olfactory and respiratory mucosae of the Corriedale sheep were examined using lectin histochemistry in order to clarify the histochemical and glycohistochemical differences between these two tissues. The olfactory epithelium was stained with 13 lectins out of 21 lectins examined, while the respiratory epithelium was positive to 16 lectins. The free border of both of the olfactory and respir...

Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent ...

Anatomic and Physiologic Considerations Nerve fibers subserving the sense of smell have their cells of origin in the mucous membrane of the upper and posterior parts of the nasal cavity (superior turbinates and nasal septum). The entire olfactory mucosa covers an area of about 2.5 cm2 and contains three cell types—the olfactory or receptor cells (which number between 6 and 10 mil l ion in each ...

The morphology of the nasal cavity in mammals with a good sense of smell includes features that are thought to improve olfactory airflow, such as a dorsal conduit that delivers odours quickly to the olfactory mucosa, an enlarged olfactory recess at the back of the airway, and a clear separation of the olfactory and respiratory regions of the nose. The link between these features and having a go...