The Chemical Senses Taste & Smell. Taste Sensation Taste Sensation.
Chapter 8 Special Senses – Chemoreceptors: Taste & Smell.
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Transcript of Chapter 8 Special Senses – Chemoreceptors: Taste & Smell.
![Page 1: Chapter 8 Special Senses – Chemoreceptors: Taste & Smell.](https://reader036.fdocuments.in/reader036/viewer/2022081506/56649cf55503460f949c43c6/html5/thumbnails/1.jpg)
Chapter 8Special Senses –
Chemoreceptors: Taste & Smell
![Page 2: Chapter 8 Special Senses – Chemoreceptors: Taste & Smell.](https://reader036.fdocuments.in/reader036/viewer/2022081506/56649cf55503460f949c43c6/html5/thumbnails/2.jpg)
Chemical Senses – Taste & SmellChemical Senses – Taste & Smell
Both senses use chemoreceptors
- Stimulated by chemicals in solution
- Taste - 5 types of receptors
- Smell - large range of chemicals
Both senses complement each other and respond to many of the same stimuli
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SmellSmell
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Olfaction – The Sense of SmellOlfaction – The Sense of Smell
Olfactory receptors are in roof of the nasal cavity
- Neurons with long cilia
- Chemicals must be dissolved in mucus for detection
Impulses are transmitted via the olfactory nerve
Interpretation of smells is made in the cortex
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Olfactory EpitheliumOlfactory Epithelium
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The Tongue and TasteThe Tongue and Taste
The tongue is covered with projections called papillae
- Filiform – pointy with no taste buds
- Fungifiorm – rounded with taste buds
- Circumvallate – large with taste buds
Taste buds are found on the sides of papillae
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The Sense of TasteThe Sense of Taste
Taste buds house the receptor organs
Location of taste buds
- Most are on tongue
- Soft palate
- Cheeks
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Structure of Taste BudsStructure of Taste Buds Gustatory cells are the receptors
- Hairs stimulated by chemicals dissolved in saliva
1 taste bud = cluster of 100 specialized cells few exposed at a time.
Taste bud lifespan is about 10 days
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Cranial Taste NervesCranial Taste NervesImpulses carried to
the gustatory complex by several cranial nerves because taste buds are found in different areas
Facial nerve
Glossopharyngeal nerve
Vagus nerve
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Taste SensationsTaste Sensations1. Sweet receptors (-OH groups)
Sugars Saccharine Some amino acids
2. Sour receptors Acids
3. Bitter receptors Alkaloids
4. Salty receptors Metal ions
5. Umami receptors (meaty/savory) Glutamate
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Developmental AspectsDevelopmental Aspects Formed early in
embryonic development
All special senses are functional at birth, but vision isn’t fully developed.
- Eyes are outgrowths of brain, born ½ size; grow mostly 1st yr & until puberty
- Baby’s focal length is ~9”.
- Reaches 20’ by age 3.