PSYC2274 Chapter Notes - Chapter 15: Taste Receptor, Taste, Cranial Nerves
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Gustation
- This is the sensory system connected to the receptors on the tongue.
- We happen to call these sensations “taste,” but there is a big difference between this and
flavor!
- Taste serves the function of discerning which chemicals we need to ingest
because they are nutritious, and which ones we should avoid because they may be
poisonous.
- Tastes are sensations evoked by solutions in the mouth that contact receptors on
the tongue and the roof of the mouth that then connect to axons in cranial nerves.
- Retronasal olfactory sensations are sensations of an odor perceived when
chewing and swallowing force an odorant in the mouth up into the nose.
- This input also enhances the taste of sweet.
- The brain combines retronasal olfactory sensations with taste sensations into flavor
which is the combination of true taste (sweet/salty/sour/bitter) and ret. olfaction!
- Gustation happens to be closely related to olfaction in structure, function and perception.
Anatomy and physiology of the gustatory system
- A major part of gustation are the taste buds.
- The taste buds are housed in the tongue papillae, and there are 3 different types.
- Fungiform papillae → these are mushroom-shaped structures that are
distributed most densely on the edges of the tongue, especially the tip. Taste buds
are buried in the surface at an average of 6 per papilla.
- Circumvallate papillae → these are large, circular structures that form an
inverted V on the rear of the tongue. The mound-like structures are each
surrounded by a trench (like a moat), and taste buds are buried in the sides of the
moats. These are much larger than fungiform.
- Foliate papillae → these are located on the sides of the tongue where it
attaches to the mouth and look like a series of folds. Taste buds are buried in
the folds.
- Filiform papillae → these are without taste function and located on the
anterior portion of the tongue.
- As mentioned, the papillae host the taste buds.
- Taste buds contain multiple taste receptor cells which can interact with taste stimuli and
respond to a limited number of molecule types.
- A tastant will dissolve in the saliva, bind to receptors on the microvilli, and cause
activation through 2 different routes:
- For salty and sour, tastants are cations (Na+, H+). entry into cell down
concentration gradient causes depolarization.
- For other tastants, activation of G-protein coupled receptors.
- Gustation contains only 5 tastes. These are:
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Document Summary
This is the sensory system connected to the receptors on the tongue. We happen to call these sensations taste, but there is a big difference between this and flavor! Taste serves the function of discerning which chemicals we need to ingest because they are nutritious, and which ones we should avoid because they may be poisonous. Tastes are sensations evoked by solutions in the mouth that contact receptors on the tongue and the roof of the mouth that then connect to axons in cranial nerves. Retronasal olfactory sensations are sensations of an odor perceived when chewing and swallowing force an odorant in the mouth up into the nose. This input also enhances the taste of sweet. The brain combines retronasal olfactory sensations with taste sensations into flavor which is the combination of true taste (sweet/salty/sour/bitter) and ret. olfaction! Gustation happens to be closely related to olfaction in structure, function and perception. A major part of gustation are the taste buds.
