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The Sense of Smell

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PRESENTATION OUTLINE

THE SENSE OF SMELL

BY NATE AND SAMUEL

WHAT IS THE SENSE OF SMELL?

  • One of the five senses of the body.
  • Undergone thousands of times a day.
  • Used to perceive and interpret odors.

PARTS OF THE OLFACTORY SYSTEM

  • Nose
  • Nostrils
  • Nasal Cavity
  • Lungs
  • Mucous Membranes
Photo by lovestruck.

PARTS OF THE OLFACTORY SYSTEM (2)

  • Olfactoroy Receptor Neurons
  • Olfactory Epithelium
  • Olfactory Nerves
  • Olfactory Bulbs
  • Hippocampus
  • Amygdala
  • Thalamus
  • Neocortex
Photo by ro0ter

HOW OLFACTION WORKS

  • Air is inhaled through the nostrils and into the nose.
  • Odor molecules in the air are filtered through nasal hairs and stick to mucous in the olfactory epithelium.
  • Molelcules in the mucous dissolve and bind to olfactory receptor neurons.
  • Neurons use molecule size to interpert odors.
  • Each olfactory neuron can detect only one specific odor, and when that odor is detected, an electrical impulses is trigger.

HOW OLFACTION WORKS (2)

  • The impulses combine in the olfactory nerves and are carried to the olfactory bulbs.
  • The olfactory bulbs process the specific combination of impulses into smells.
  • From the bulbs, the smells travel to the amygdala, hippocampus, thalamus, and neocortex where they are processed, alerted to your consciousness, and stored into your memory.
Photo by Dave77459

Untitled Slide

SMELL AND TASTE

  • Smell and taste are very closely related.
  • Taste is used to determine if the food is sweet, salty, bitter, sour, etc., while smell is used to distinguish 75-90% of the flavor.
  • When you chew food, odors rise up into the nasal cavity where they are processed into flavors and combined with your sense of taste.
  • Without smell, you wouldn't be able to distinguish or savor many foods.
Photo by Gerg1967

SMELL AND MEMORY

  • Smell is very closely related to memory.
  • Smell is processed in the olfactory bulbs which are near an area that contains the amygdala and hippocampus, which process emotion and memory.
  • When the olfactory bulbs are stimuled, the neurons in the hippocampus and amygdala can be too, triggering strong memories and emotions.
Photo by VinothChandar

OLFACTORY DISORDERS

  • About 15% of elderly people have an olfactory disorder.
  • Caused by smoking, genetics, aging, hormonal disturbances, infections, head injuries, chemicals, radiation, and other diseases.
  • Anosmia - Can't smell specific scents or can't smell at all.
  • Hyposmia - Worsened sense of smell.
  • Parosmia - Odors smell differently than normal.

SMELL IN ANIMALS

  • Smell is extremely important in animals.
  • Animals rely on their sense of smell to see, communicate, and find prey.
  • Determined by the size of their olfactory epithelium and concretion of olfactory cells in it.
  • Dogs have an olfactory epithelium 20x bigger than humans along with 100x the cell concentration.
Photo by wsilver

HOW TO IMPROVE YOUR SENSE OF SMELL

  • Move your nose closer to what you're smelling.
  • Use quick, jerky sniffs.
  • After you smell, think about the smell and try to describe it.
Photo by Ennor

WHY DOES SMELL MATTER?

  • Helps animals tell apart objects, communicate, and find pray.
  • Helps attract mates.
  • Helps us express ourselves.
  • Helps us taste.
  • Helps trigger memories and emotion.
  • Alerts us of dangers such as fires and gas leaks.
  • Is pleasing.
Photo by kimberlykv

FUN FACTS

  • The main smells are camphor, musk, floral, peppermint, ether, pungent, and putrid.
  • Humans have forty million olfactory neurons.
  • Although we can detect 1 trillion different smells, most are similar, and we can only tell apart 10,000.
  • Women have a better sense of smell than men.
  • People smell worse in the morning and best in the summer.
  • Smell loss is related to race.

REFERENCES

  • George, Nancie. "10 Incredible Facts About Your Sense of Smell." EverydayHealth.com. Everyday Health, 03 Oct. 2014. Web. 22 Apr. 2017. . "How Do We Smell? - Rose Eveleth." YouTube. N.p., 19 Dec. 2013. Web. 22 Apr. 2017. .

REFERENCES (2)

  • "How Smells Trigger Memories." YouTube. N.p., 20 July 2015. Web. 22 Apr. 2017. . "How to Master Your Sense of Smell - Alexandra Horowitz." YouTube. N.p., 09 Jan. 2017. Web. 22 Apr. 2017. . "The Smell Report." The Smell Report - The Human Sense of Smell. N.p., n.d. Web. 22 Apr. 2017. .

REFERENCES (3)

  • "How Smell Works." HowStuffWorks. N.p., 29 Oct. 2007. Web. 22 Apr. 2017.
  • "Taste & Smell: Crash Course A&P #16." YouTube. N.p., 27 Apr. 2015. Web. 22 Apr. 2017. .
  • "Taste & Smell: Crash Course A&P #16." YouTube. N.p., 27 Apr. 2015. Web. 22 Apr. 2017. .