NEURO #ANATOMY OF THE OLFACTORY SYSTEM : How some smells induce tears and sniffing in you❓

😤 Olfactory receptors1️⃣ are the most important cells of the olfactory epithelium and they are the first order neurons of the cranial nerve I

😤There are approximately 100 million such receptors in the olfactory epithelium found along the roof of the nasal cavity including the superior and upper middle conchae

😤Olfactory receptors project through the cribiform plate in the ethmoid bone

😤They have multiple cilia immersed in a surrounding matrix of mucus and a long dendrite

😤Odiferous chemicals get dissolved in this mucus and then trigger the olfactory receptors

😤The impulses pass through the neuron to the olfactory bulb (lies in base  of frontal  cortex in anterior  fossa), which has projections to cortical areas

😤The primary olfactory area in the temporal lobe process such informations through it's connections with the hypothalamus, thalamus and frontal cortex

😤The other major cell type is basal cells2️⃣ found deep to the olfactory neurons (olfactory neurons have a half-life of one month) and replace them, as they mature

😤3️⃣Sustentacular or supporting cells constitute the columnar mucus epithelium found between the receptors

😤There are 4️⃣Olfactory (Bowman’s) glands found in the connective tissue beneath the olfactory epithelium which produce the mucus in which the odiferous chemicals dissolve

❓➡️ 🅰️ Finally answer to the question

😤The innervation of the olfactory epithelial cells from cranial nerve VII (facial nerve) explains the tears and sniffing evoked by some smells.

Reference: Tortora GJ, Grabowski SR. Principles of Anatomy and Physiology, 8th edn. New York, NY: HarperCollins, 1996; pp. 454–5

#smell , #Olfaction , #PhysiologyForExams , #NeuroAnatomy , #anesthesiology