Chemical Senses
Terms
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- What are the two chemical senses?
- Gustation and Olfaction
- What are the 4 qualities of taste?
-
Bitterness, sourness, sweetness, saltiness
Acronym: BSSS - Flavor (not taste) is a composite of what?
- Olfaction and Gustation
- About 10,000 tastebuds exist in what four areas of the mouth?
- Tongue, Palate, Pharynx, and Larynx
- What are Papillae?
- Small protuberances of the tongue around which most receptors lie.
- What qualities of taste does the tip of the tongue detect?
- Sweet and Salty
- What quality of taste does the side of the mouth detect?
- Sourness
- What quality of taste does the back of the mouth detect?
- Bitterness
- Gustatory information is transmitted through which cranial nerves?
- 7, 9, 10
- Info. from the __________ part of the tongue travels through the ____________, which is branch of which cranial nerve?
- anterior, chorda tympani, CN 7
- What is the name of CN 7?
- Facial
- Info. from the _________part of the tongue sends info. through which CN?
- posterior, CN 9
- What is the name of CN 9?
- Glossopharyngeal
- Info. from the _________ and _________ is carried by which CN?
- palate, epiglottis, 10
- What is the name of CN 10?
- Vagus
- What is the first relay station in the gustatory pathway?
- Nucleus of the solitary tract (in medulla)
- Following this relay, what is the next station?
- Ventral posteromedial nucleus (in the thalamus)
- Next, the thalamic neurons send axons where?
- Primary gustatory cortex (in the anterior insula-frontal operculum)
- Then, info. is sent to the_____?
- Secondary gustatory cortex (in orbitofrontal cortex)
- Gustatory cells turn over every ____days
- 60
- What anatomical area is activated by odorants?
-
Bipolar olfactory receptor neurons
Acronym: BORN - Where are the BORN located?
- Olfactory mucosa
- Olfactory cells turn over every _____days
- 60
- How do the receptor cells on the olfactory cilia get stimulted?
- Odorous molecules dissolve in mucus
- Where do axons of olfactory receptor cells enter the skull?
- Through small holes in cribriform plate
- What is the purpose of free nerve endings of trigeminal contained in mucosa?
- Mediation of sensations of pain that can be produced by some irritating chemicals like ammonia
- Where are the olfactory bulbs?
- At the base of the brain on ends of stalk-like olfactory tracts
- Each olfactory cell sends how many axons into olfactory bulbs?
- One
- This single axon synapses with dendrites from what kind of cell?
- Mitral
- Axons of the mitral cells travel to the rest of the brain through what?
- Olfactory tract
- Where do the axons of the mitral cells terminate?
- Some in ipsilateral areas; others cross and enter the olfactory nerve and terminate in the contralateral olfactory bulb
- How is the primary olfactory cortex unique among sensory systems?
- It receives direct input from secondary sensory neurons WITHOUT intervening thalamic relay
- Olfactory tract axons project directly to the __________, ___________, and __________
- Piriform cortex, amygdala, entorhinal cortex
- Primary olfactory cortex projects to several seondary olfactory areas including __________, __________, __________, and __________
- Hypothalamus, Hippocampus, Orbitofrontal cortex, Dorsomedial nucleus of thalamus
- Olfactory disturbances can be subdivided into how many groups?
- 4
- Quantitative abnormalities in smell include what subjective experiences?
- Loss or reduction of sense of smell OR increased olfactory acuity
- Loss or reduction of smell is known as?
- Anosmia or hyposmia
- What might cause anosmia or hyposmia?
- Problems at the nasal, neuroepithelial, or central level
- If the anosmia or hyposmia is bilateral, what might the patient complain of?
- Ageusia (loss of taste)
- Increased olfactory acuity is known as?
- Hyperosmia (which is very rare, if it exists)
- Qualitative abnormalities in smell (the 2nd subgroup of disorders of smell), including distortions or illusions of smell, are known as what?
- Dysosmia or parosmia
- With what mood disorder might dysosmia or parosmia be associated?
- Depressive illness
- Olfactory hallucinations/delusions (the 4th subgroup of disorders of smell) originate where
- At the central level
- What is the most common etiology of olfactory hallucinations/delusions?
- Temporal lobe seizures (uncinate fits)
- The fourth subgroup of disorders of smell is knows as Higher-order loss of discrimination or ___________
- Olfactory agnosia
- Olfactory agnosia is characterized by what?
- Perceptual aspects intact, but can't recognize