Chapter 53 Flashcards
What are the five sensations of taste?
- Sour
- Salty
- Sweet
- Bitter
- Unami
What causes sour and salty tastes?
- Sour is caused by acids
- salty is caused by ionized salts like Na+
What causes sweet tastes?
-plethora of chemicals like:
–> sugars, glycols, alcohols, aldehydes, ketons, amides, esters, AA, sufonic acids, halogenated acids, salts of lead and beryllium
—> basically organics
What causes bitter tastes? What is the significance?
- caused by nitrogen containing long-chain organics and ALKALOIDS
- tells you if something is poisonous
What causes unami (delicious) tases?
- L-glutamate (aged cheese)
- really good pot-roast and the lube’s ranch wings
What is the “sampling” part of the tast cell?
-the taste pore which contains microvilli
Neural pathways for taste?
-Ant. 2/3 of tongue–> lingual N.–> chorda tympani–> facial N–> solitary tract–> VPM thalamus–> primary sensory cortex
Post. 1/3–> glossopharyngeal N.–> solitary tract–> VPM thalamus–> primary sensory cortex
What is the location of taste preference?
CNS
What changes taste preference?
- diabetes/insuline depletion–> sweet craving
- Salt-depletion–> cravings for drinks with high NaCl concentration
Bad smell–> rejection of food
Taste aversion–> negative taste preferences are stored in memory
What is the process of olefactory stimulation?
- odorant substance binds to heptahelical receptor on cilium
- increases cAMP via adenylyl cyclase
- cAMP causes influx on Na+
- transmits AP through olfactory N.
How quickly do olfactory receptors adapt?
- Fast
- 50% within the first second or so
- the rest slowly after
How else does the olfactory system adapt to smells?
-feedback inhibits the olfactory N.
What does the new olfactory pathway do?
- Lateral olefactory pathway
- composed of the prepyriform and pyriform cortex
- feed the older part and learns to like or dislike
What is the pathway and purpose of the old olfactory pathway?
- medial olfactory area
- contains septal nuclei
basic behavior
