Lec 18/19 Flashcards
Olfactory transduction mechanism in receptor cilia:
What happens following the binding of a G-olf protein with a odorant molecule?
the alpha subunit of G-olf in turn activates adenylyl cyclase, which produces cAMP.
What type of of receptor is associated with the olfactory transduction mechanism?
G-olf receptor
Olfactory transduction mechanism in receptor cilia:
what happens after the activation of the effector adenylyl cyclase and the production of its 2nd messenger?
cAMP binds to a cAMP-gated cation channel and by doing this, the channel increases permeability to Na, k, and Ca. this allows a net inward current and leads to the depolarization of the cell as well as Ca2+ increase
Olfactory transduction mechanism in receptor cilia:
What happens following membrane depolarization after the opening of the nonselective cation channel?
the increase in Ca2+ opens Ca activated Cl- channels which produce more depolarization because because of relatively high Cl concentrations of olfactory receptor neurons.
Olfactory transduction mechanism in receptor cilia:
What happens after the depolarization due to Ca2+ activated Cl- channels?
If the receptor exceeds the threshold, it triggers action potentials in the soma that travel down the axon and into the brain.
What are the 3 ways to terminate an Olfactory response?
- oderant diffuses away
- mucous layer enzymes break it down
- cAMP in receptor cell activates other signalling pathways.
What process depends on receptor potentials mediated through the effect of an environmental stimulus acting on a receptor molecule.
Sensory transduction
What are the 5 steps to the Sensory transduction pathway?
ERTRS
- Environment stimulus
- Receptor molecule
- Transduction channel
- Receptor potential
- spike train or Neurotransmitter release
what are the 4 types of sensory transduction?
(TMCV) Thermoreception Mechanoreception Chemoreception Visual transduction
Which type of Sensory transduction is involved with hearing and touch?
Mechanoreception
Which type of sensory transduction is involved with taste and smell.?
Chemoreception
What senses are involved with mechanoreception?
hearing and touch
What senses are involved with chemotransduction?
taste and smell
What types of sensory transduction channel produces a “transient” response ?
TRP channel
What does TRP stand for?
Transient receptor potential
Are TRP receptor channels selective or non selective? and if so what are they selective to?
not selective and sometimes can be permeable to Ca
What are the “feelings” or sensations that are involved with TRP channels?
PIHTT "PIT" Pain itch heal taste touch
TRP channels can be activated or modulated by what range of environmental stimuli?
List:
TIP2M temperature ph mechanical stress interaction with chemicals 2nd messengers
What is the abbreviation for the “vanilloid” subfamily?
TRPV
What is the abbreviation for the “classical” subfamily?
TRPC
What is the abbreviation for the “melastatin” subfamily?
TRPM
What is the abbreviation for the “ankyrin” subfamily?
TRPA
How will A warmth thermoreceptor that experiences slow increasing change in temperature adjust its firing rate?
increase in fire rate
How will A cold thermoreceptor that experiences slow increasing change in temperature adjust it’s firing rate?
increase in fire rate
Which type of thermoreceptor has a broader temperature response?
cold receptors
At what temperature does a cold receptor reach its max firing rate?
~25ºC
At what temperature does a hot receptor reach its max firing rate?
~46ºC
Are all neurons sensitive to temperature?
yes
What is the diameter of the small areas on your skin that are sensitive to changes in temperature?
1mm
T or F : A single thermoreceptor will be sensitive to both heat and cold.
False; they either cold or heat receptors.
What type of receptor is most likely free nerve endings?
thermalreceptors (cold and warm)
thermosensation is likely to be mediated by ______ channels. This was discovered due to tissue cultures.
ion channels
What are the mammalian thermal sensitive channels?
TRPV1-4 (1 is most important)
TRPM8
TRPA1
What activates the thermosensitive channel TRPV1?
capsaicin