Chapter 8 - Chemical Senses Flashcards
What are the 3 steps common to all 5 senses?
- physical stimulus (light, sound, …)
- Set of events by which the stimulus is transduced into a set of nerve impulses
- A response to the message, often in the perception or conscious experience of sensations
What are the three components of flavor?
Taste + olfaction + somatosensory
Where can taste receptors be found?
Palate, pharynx, epiglottis, tongue
What do taste cells do?
They transduce sensory stimuli into signals that are sent to the brain via the gustatory nerves
Are taste cells neurons? Can they generate AP?
They are not neurons but some can have Na+ channels that can generate AP
Explain what each cell type does
Type 1 cell: glial-like support cells
Type 2: “receptor cells”: express metabotropic receptors for sweet, bitter and umami. Cells tend to be narrowly tuned to a single taste quality
Type 3: “presynaptic cells” express receptors for sour and salty. An average type 3 cell responds to ~3 taste qualities
What do type 2 cells use to transduce chemical tastants?
G-protein coupled receptors
How do type 2 cells fire AP? Keywords
- gustducin
- Ca dependent cation channel
- voltage gated Na channels
- use of ATP as a transmitter
How does the transduction mechanism for salty tastants work?
See photo album
How does the transduction mechanism for sour tastants work?
See album
Why can we say that type 3 cells respond to multiple taste qualities?
Type 2 cells release ATP. This can activate neighboring presynaptic cells.
Define the structure of a taste bud
A collective unit involving extensive cell-to-cell interactions
What is population coding?
Different tastes have different spatial and temporal patterns of activation in cortex, and this is presumed to be the neural “fingerprint” of the taste.
How does the odorant depolarize the olfactory cell?
See pic album
Cells expressing a given gene go to how many glomeruli in each bulb?
2
