Taste 1 Lecture 13 Flashcards
What sort of sense is taste and smell?
Chemical sense, This is what module B is about.
Chemicals are either dissolved in water or air and that is how they are tasted or smelt.
What do taste and smell senses have in common?
The sensory inputs merge at the highest level of processing pathway and provide a common sense of flavour that is characteristic of food and drinks we eat
What do animals and humans depend on smell for?
To detect stimuli of food, noxious stimuli and potential mates.
What are the senses of taste and smell connected with?
Basic internal needs including thirst, hunger, emotion and certain forms of memory
Amagdyla, hippocampus extensions from the processing pathways.
Describe the pathways of the taste and smell
Neural information fro each pathway is processed in parallel and merged at higher levels in the cerebral cortex.
What are the types of papillae, their size, location and innervation?
Papillae:
- Circumvallet, large, back of tongue, cranial nerve IX (glossopharyngeal)
- Foliate Papillae, sides of tongue, Mixed innervation
- Fungiform papillae, small, 2/3 front tongue, innervation from VII CN, (facial)
What do papillae contain?
They all contain different taste receptors that can detect certain tastes. The receptors are randomly spread and the tongue is not divided into taste areas.
(papillae contain taste buds, which are made up of taste cells)
Describe how many taste buds humans, have and their distribution amongst papillae:
~4000 in total
Circumvallet have hundreds of taste buds per papillae.
Foliate have dozens-hundreds
Fungiform have 1-4 per
Describe the position of taste buds on papillae
There are trenches down the sides of the papillae and this is where the taste receptors are located. Saliva and food mixes down here.
Saliva is essential for taste recognition.
Describe the anatomy of a papillae:
Papillae contain taste buds
Taste buds are made up of taste cells, 50-150 per bud.
Taste cells form onion like structures.
Taste cells have taste receptors
What do taste cells synapse with?
The gustatory afferent axons.
Describe taste cells and the onion like structure.
Taste cells are bipolar and have microvilli that come together to form a taste pore on the surface of the bud. This is where food interacts.
Supporting cells provide metabolic and structural support to the taste cells.
Basal cells are stem cells that will proliferate to replace dying taste cels.
All these cells are found in the onion like structure..
What is the time life of a taste cell?
Two weeks therefore basal cells are very active.
What are the types of taste receptors in terms of functional classification
3 g coupled protein receptors
2 ion channels
Where else can taste receptors be found?
Gut, pancreas and lungs
What are the five major tastes?
Sweet Salty Sour Bitter Umami
What are the ligands for the five major tastes?
Sweet = Glucose/sugars/sweetners Salty = Na Sour = H Bitter = Quinine and others Umami = Amino Acids
What do the five major taste ligand inform us of?
Sweet = Energy Salty = Ionic Sour = Changed pH (rotting food warning) Bitter = toxic warning Umami = protein
