Sense of smell

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SENSE OF SMELL EXPERT VISION ACADEMY

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Transcript of Sense of smell

Page 1: Sense of smell

SENSE OF SMELL

EXPERT VISION ACADEMY

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Smell

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Chemical Senses: Taste and Smell

Both senses use chemoreceptors Stimulated by chemicals Taste has four types of receptors Smell can differentiate a large range of

chemicals Both senses complement each other and

respond to many of the same stimuli Olfaction (smell) and gustation (taste) Both project to cerebral cortex & limbic

system Evokes strong emotional reactions

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Olfactory organs•Contain olfactory receptors and supporting epithelial cells•Cover parts of nasal cavity and a portion of the nasal septum

Olfactory receptors•Chemoreceptors•Respond to chemicals dissolved in liquids

Olfactory Epithelium•Located on roof of nasal cavity•Contain olfactory receptor cells with columnar supporting cells•Covered by mucous to trap airborne molecules

Sense of Smell

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Olfactory Epithelium

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Cells of the Olfactory Membrane

Olfactory receptors bipolar neurons with

cilia or olfactory hairs Supporting cells

columnar epithelium Basal cells = stem cells

replace receptors monthly

Olfactory glands produce mucus

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Sense of Smell

Air entering the nasal cavity must make a hairpin turn to stimulate the olfactory receptors before entering the respiratory passageway below

Sniffing also brings the air superiorly across the olfactory

epithelium intensifies the smell

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Olfactory tract

Olfactory bulb

(a)

Nasalconchae

Route ofinhaled air

Olfactoryepithelium

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Mitral cell (output cell)

Olfactorygland

Olfactorytract

Olfactoryepithelium

Filaments of olfactory nerve

Cribriform plate of ethmoid bone

Lamina propria connective tissue

Basal cell

Supporting cell

Dendrite

Olfactory cilia

Olfactory bulbGlomeruli

Axon

Olfactory receptor cell

Mucus

Route of inhaled aircontaining odor molecules(b)

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Olfactory Cells

Dendrites of each olfactory cell called olfactory cilia

extend into the nasal cavity

Olfactory axons project upward through the foramina in the

cribriform plate of the ethmoid bone of the skull synapse on neurons within the olfactory nerve

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Physiology of Smell

Series of events the chemical must be volatile

it must be in the gaseous state as it enters the nasal cavity

the chemical must be water soluble so that it can dissolve in the fluid containing the olfactory

epithelium the dissolved chemicals stimulate the olfactory

receptors by binding to protein receptors in olfactory cilium membranes

the generation of APs in the olfactory cells an impulse travels through the olfactory cell axons to

the olfactory nerve where the smell sensation is transmitted to the brain

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OLFACTORY PATHWAY

As air enters the nasal passageway the level of odor-producing chemicals dissolve in the mucus membrane

With in the mucus membrane the olfactory cilia capture the chemicals

After reaching a threshold level it is passed to the olfactory nerves located in the olfactory bulb

The impulse passes through the olfactory tract and into the thalamic and olfactory centers of the brain for interpretation, integration, and memory storage.

The sense of smell can create powerful and long-lasting memories. That often persist from early childhood to death

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Olfactory Nerve Pathways

Olfactory receptor fibers synapse with neurons in the olfactory bulbs (cranial nerve I).

Impulses travel along the olfactory tracts Impulses are interpreted in olfactory cortex. Olfactory receptor neurons are in direct contact with

the environment and can be replaced if damaged. Olfactory receptors undergo sensory adaptation

rapidly Sense of smell drops by 50% within a second after

stimulation

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Transmission of smell signals to CNS

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Abnormalities

Anosmia – absence of sense of smell

Hyposmia – diminished olfactory sensitivity

Dysosmia – distorted sense of smell

More than 75% of humans over the age of 80 have an impaired ability to identify smells

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Anosmia

Absence of the sense of smell

Trauma Colds or allergies producing excessive

mucus Polyps causing blockage 1/3 are from zinc deficiency


Sense of Smell...Bears are thought to have the best sense of smell of any animal on earth. For example, the average dog’s sense of smell is 100 times better than a human’s. A blood

Sense of Smell...Bears are thought to have the best sense of smell of any animal on earth. For example, the average dog’s sense of smell is 100 times better than a human’s. A blood

Does the strength of your sense of smell have a correlation with the strength of your … · 2020-03-24 · sense of smell. In the below average LTM category, 53% had a good sense

Does the strength of your sense of smell have a correlation with the strength of your … · 2020-03-24 · sense of smell. In the below average LTM category, 53% had a good sense

12 pairs Olfactory Nerves Sense of smell.

12 pairs Olfactory Nerves Sense of smell.

The Medieval Sense of Smell, Stench and Sanitation€¦ · The Medieval Sense of Smell, Stench and Sanitation Dolly Jørgensen Smell is uncontainable. Odour wafts over boundaries

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Smell and Taste.. Smell. Olfaction-The sense of smell. Ansomics/ hyposmia-Lack of the functioning olfaction. Pheromones-Chemical signals released.

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The Sense of Smell - National Institute of Environmental ...€¦ · nose to the brain, and is thus necessary for a proper sense of smell. With this in mind, its potential functions

The Sense of Smell - National Institute of Environmental ...€¦ · nose to the brain, and is thus necessary for a proper sense of smell. With this in mind, its potential functions

Sense of smell and taste

Sense of smell and taste

Sense of Smell - Badger Anatomy & Physiologybadgeranatomyphysiology.weebly.com/uploads/1/7/6/1/... · 2018-08-29 · The sense of smell gets bored easily. When entering a bakery or

Sense of Smell - Badger Anatomy & Physiologybadgeranatomyphysiology.weebly.com/uploads/1/7/6/1/... · 2018-08-29 · The sense of smell gets bored easily. When entering a bakery or

THE SENSE OF SMELL (Science 1º Primaria)

THE SENSE OF SMELL (Science 1º Primaria)

Unravelling the malaria mosquito's sense of smell · 2015-09-22 · Unravelling the malaria mosquito's sense of smell: Neural and behavioural responses to human-derived compounds

Unravelling the malaria mosquito's sense of smell · 2015-09-22 · Unravelling the malaria mosquito's sense of smell: Neural and behavioural responses to human-derived compounds

Smell Smell and Taste - University of Sussex · 2003-11-13 · 1 Smell and Taste Perception and Attention Course George Mather Smell • Smell is usually considered a minor sense

Smell Smell and Taste - University of Sussex · 2003-11-13 · 1 Smell and Taste Perception and Attention Course George Mather Smell • Smell is usually considered a minor sense

The sense of smell

The sense of smell

University of Groningen Biophysics of the sense of smell Stuiver, … · 2016. 7. 4. · of the sense of smell proefschrift ter verkrijging van de graad v an doctor in de wis- en

University of Groningen Biophysics of the sense of smell Stuiver, … · 2016. 7. 4. · of the sense of smell proefschrift ter verkrijging van de graad v an doctor in de wis- en

Sense of Smell & Famous Deaths

Sense of Smell & Famous Deaths

sense of smell

sense of smell

Sense of Smell - National Institute of Environmental ... · Bears are thought to have the best sense of smell of any animal on earth. For example, the average dog’s sense of smell

Sense of Smell - National Institute of Environmental ... · Bears are thought to have the best sense of smell of any animal on earth. For example, the average dog’s sense of smell

Yonkers Public Schools · Web viewOur sense of smell works the same way. Things like old milk or rotten fruit give off a bad smell, so our sense of smell warns us to stay away from

Yonkers Public Schools · Web viewOur sense of smell works the same way. Things like old milk or rotten fruit give off a bad smell, so our sense of smell warns us to stay away from

Human memory. Sense memory Sense memory is the knowledge of what your senses are telling you, for instance if you were to smell the smell of dog it would.

Human memory. Sense memory Sense memory is the knowledge of what your senses are telling you, for instance if you were to smell the smell of dog it would.

Orientation in space using the sense of smell · Orientation in space using the sense of smell Anna Maria Kleemann Munchen 2010¨

Orientation in space using the sense of smell · Orientation in space using the sense of smell Anna Maria Kleemann Munchen 2010¨

Olfaction (the sense of smell) - Department of Molecular ...mcb.berkeley.edu/courses/mcb160/Fall2006/lslides/10_06_06.pdf · Olfaction (the sense of smell) •Mammals can detect upwards

Olfaction (the sense of smell) - Department of Molecular ...mcb.berkeley.edu/courses/mcb160/Fall2006/lslides/10_06_06.pdf · Olfaction (the sense of smell) •Mammals can detect upwards