Chemoreception - Taste Flashcards
Where do you find chemoreceptors for taste?
In taste buds
What is a taste pore?
It is a small opening in a taste bud where the fluids in the mouth come into contact with receptor cells
Name the 3 types of lingual papillae
- filiform papillae
- fungiform papillae
- circumvallate papillae
Which of the 3 lingual papillae do not contain taste buds?
Filiform papillae
How many taste buds to fungiform papillae contain?
5 taste buds each
How many taste buds to circumvallate papillae contain?
100 taste buds each
What evokes the sensation of taste?
Receptor cells coming into contact with chemicals in what you are eating
The binding of a tastant with a receptor cell will produce?
A depolarising receptor potential due to the ionic Change
How are taste bud components constantly renewed?
From epithelial cells around it which differentiate into supporting cells and then into receptor cells
Where are sensory inputs sent to?
- conveyed to the brain stem
- sent to the thalamus at the cortical gustatory area
- sent to the hypothalamus and limbic systems
Which cranial nerves synapse with taste buds?
- VII
- IX
- X
Name the five primary tastes
- salty
- sour
- sweet
- bitter
- umami
Name 2 types of taste cells based on their response to stimuli
- type III or presynaptic cells
- type II or receptor cells
Which taste cells detect salty and sour tastes?
Type III or presynaptic cells
Which taste cells detect sweet,bitter and umami tastes?
Type II or Receptor cells
State pathway for Type III cells for a salty taste
- salty taste stimulated by chemical salts
- NaCl causes an ionic change and depolarises the cells
- this releases serotonin
- serotonin excites the primary gustatory neuron
State pathway for Type III cells involved wit sour tastes
- sour taste is caused by acids that contain a free hydrogen ion
- the hydrogen ion will block potassium in the cell membrane
- this results in passive efflux of potassium
- this creates a depolarising receptor potential
- this results in serotonin release and excites the primary gustatory neuron
What G protein is involved tasting bitter,sweet and umami
Gustducin
State chemical pathway for Type II taste cells
- g protein receptors are used
- gustducin will activate multiple signal transduction pathways
- pathways release calcium
- calcium initiates ATP release from the cells
What is umami taste triggered by?
Amino acids - glutamate
Other than chemicals - what is taste perception also influenced by?
- odour
- temperature
- texture
- psychological factors
What is specific hunger?
If you lack a certain nutrient in the body your body will crave the substance
What are receptors for taste and smell called?
Chemoreceptors
