Smelling Tiffany Wang Anna Laurence Brit Sharon Aliza Heeren Timothy Chong

Introduction to smelling Chemical sense Humans can distinguish between thousands of different odors 7 main categories of smell: o Camphoraceous, musky, floral, Pepperminty, ethereal, pungen, putrid

Introduction to Smell Continued Attraction of smell o Every person has a different smell o Opposites attract o Attraction between mother and child o Pheromone Animals use smell for: o Marking territory o Finding food o Finding a mate

Structure of olfactory system At the top part of the nasal cavity.8 to 1.5 square inch From 10 million to 100 million smell receptors Most smell comes from odoriferous molecules in inhaled air or through nasopharynx

Signals from the olfactory tract are transmitted to the brain to the -olfactory cortex, -structures of the limbic system: hippocampus, amygdala, and hypothalamus. Overview of the Science Behind Smell

The limbic system is involved with emotional behavior and memory. This is why a certain smell often brings back memories associated with the object. The olfactory system is the only system that does not go through the thalamus, rather the signal goes straight to the temporal lobe and the limbic system

The In Depth Neuroscience Chemicals that act as stimuli, called odorants, interact with olfactory receptor neurons in the olfactory epithelium— a membranous sheet that lines the interior of the nose

The receptor neurons send signals to neurons in the Olfactory Bulb. Those neurons then send the message to the pyriform cortex in the temporal lobe The receptor neurons also project to a the hypothalamus and amygdala.

How does this Happen? The Olfactory Epithalium has many terminals on it, Each one containing millions of sensory neurons On every terminal there are receptor sites which, when bound to an oderant, trigger an action potential The axon terminals of the olfactory sensory neurons are in the olfactory bulb, so the synapse that sends the message to the next neuron occurs there, in a structure called the Glomeruli

There are different types of olfactory sensory neurons. Certain stimuli have a stronger bond with each type. Each type ends its action potential in a different glomeruli From there, signals are relayed to various other parts of the brain.

A Visual Representation

Olfactory disorders Anosmia Dysosmia Hyposmia Euosmia Cacosmia Hyperosmia Phantosmia =

Causes of olfactory disorders Severe upper respiratory infection Psychosis! Inflamed mucous membrane Tumor Medication Diseases Head injury/brain damage Hormonal disturbances Before migraines

Activity "Smell the Rainbow" 1. We will give everyone a cup full of skittles. 2. Partner up with the person sitting next to you. 3. Choose who will go first for the activity. 4. The partner #1 must close their eyes and pinch their nose shut. 5. The partner #2 will then choose a color skittle and give it partner #1 to eat. 6. Partner #1 will be asked to identify what flavor skittle they just ate. 7. After 30 seconds partner #1 may unplug their nose and will again be asked to identify what flavor skittle they just ate. 8. Partner #2 will then reveal the true flavor of the candy. 9. Switch roles. Could you identify the true flavor of the candy? If so, when? Did your taste sensations change when you opened your nose?

Activity Explanation With nose closed you are relying on the taste receptors on your tongue. Tongue can only perceive sweet or sour. Not enough to identify flavors. After sucking on candy for awhile olfactory receptors may come into play allowing you to identify the flavor. Scent molecules from the candy travel into the nasal passages through a "back door" (passage at back of the throat). Molecules arrive at the olfactory bulb and are recognized by olfactory receptors, which identify the specific flavor of the molecule. When you unplug your nose, the olfactory bulb can perform normally and it is easier to identify the flavor of the candy.

Bibliography Boyce, J. M., and G. R. Shone. Effects of Ageing on Smell and Taste. Rep. no. PMC Vol. 82. Cardiff: Postgrad Med J, PubMed. Web. 23 Oct "Deviated Septum." Mayo Clinic. 16 July Web. 23 Oct "Exploratorium Human Body Explorations: The Nose Knows." Exploratorium. N.p., n.d. Web. 23 Oct Fortin, Jacques. Major Systems of the Body. Ed. Francois Fortin. Milwaukee, WI: World Almanac Library, Print. Landis, B. N., J. Frasnelli, and T. Hummel. Euosmia: A Rare Form of Parosmia. Rep. no Vol. 1. Dresden: Acta Otolaryngol, PubMed. Web. 23 Oct Leopold, Donald. Distortion of Olfactory Perception: Diagnosis and Treatment. Rep. Vol. 27. Omaha: Oxford UP, Oxford Journals. Web. 23 Oct Magill. Vol. 2. Pasadena: Salem, Print. Mapes, Diane. "Phantom Smells May Be a Sign of Trouble." Msnbc.com, 10 Nov Web. 19 Oct < may-be-a-sign-of-trouble>. "Olfactory Dysfunction and Disorders." Utmb Health. University of Texas. Web. 23 Oct < htm>.

Bibliography (Continued) Purves, D., and GJ Augustine, eds. Neuroscience. Ed. D. Fitzpatrick. 2nd ed. Bethesda: National Center for Biotechnology Information, The Organization of the Olfactory System. NCBI. Web. 22 Oct Rayner, Claire, P. B. C. Fenwick, and John Reckless. The Rand McNally Atlas of the Body and Mind. New York: Rand McNally, Print. "Sense-sational Nutrition." MotherNature.com. Web. 23 Oct < smell-problems_1017.html>. "Smell Disorders." National Institute on Deafness and Other Communication Disorders [NIDCD]. July Web. 19 Oct "Smell and Taste." Psychology Basics. Ed. Frank N. Major, Jason. "Losing Sense of Smell May Predict Psychosis." The University of Melbourne | News. The University of Melbourne, 1 Dec Web. 23 Oct “Smell and Taste." Psychology Basics. Ed. Frank N. Magill. Vol. 2. Pasadena: Salem, Print. Turkington, Carol. "Smell, Sense of." Encyclopedia of Brain and Brain Disorders. 2 nd ed Print. "What Causes Olfactory Hallucinations (phantosmia)?" Mayo Clinic. 27 Mar Web. 23 Oct