Sensory systems Flashcards
Smell arises from nerve signals originating in ____ ____. Molecular components of this process include ____ proteins that bind ____, which activates a G protein called ____. This binds ____, activates ____ ____, stimulating ____ synthesis.
- nasal epithelia
- 7TM
- odorants
- Golf
- GTP
- adenylate cyclase
- cAMP
Smell:
cAMP binds to a ____-____ ion channel in the cell membrane allowing ____ to ____ the cell, starting the ____ signaling process.
- cAMP-gates
- cations
- enter
- nerve
Humans have only about ____ of their odorant receptors ____, whereas rodents a large percentage of their ____ receptors active. Olfactory receptors (ORs) are similar in structure to the ____-____ ____ involved in epinephrine signaling.
- 30%
- active
- 1000
- beta-adrenergic receptors
Each olfactory neuron synthesizes only a single ____. This differs from individual taste buds, which each synthesize ____ ____ for tastes.
- OR
- several receptors
We are able to perceive a VERY wide range of smells, due to the ____ ____ of signals from the many different ____ at the end of ____ cells.
- combinatorial mixing
- 7TMs
- olfactory
Olfactory receptor signaling proceeds via 7TM receptors that synthesize cAMP when an ____ binds to the 7TM (through the usual mechanisms). cAMP binds to a channel protein that opens when cAMP binds to it, allowing ____ and ____ into the cell, thus starting the signal.
- odorant
- Ca++
- Na+
Smell neurons ____ in very different regions of the ____.
- terminate
- brain
Taste sensing is related to smell. Not all tastes have ____, however. In contrast to smell, we only have _ primary tastes we detect through taste buds located on distinct areas of the tongue. The five primary tastes are ____, ____, ____, ____, and ____.
- odors
- 5
- sweet, sour, bitter, salty, umami
Taste buds contain about ____ cells with ____ projections that are rich in taste receptors. About __-__ 7TM receptors are involved in taste. Not all primary tastes are associated with ____ ____, however.
- 150
- microvilli
- 50-100
- 7TM receptors
Salty tastes are detected by passage of the ions directly through ____ ____ on the tongue. One class of these channels is sensitive to ____, which obscures the taste of salt and lowers ____ ____ relating to sodium.
- ion channels
- tongue
- amiloride
- neuron activity
A G protein associated with the taste receptors that use 7TM receptors is called ____.
-gustducin
Whereas individual olfactory receptors are uniquely expressed on each olfactory neuron, with direct ‘wiring’ to distinct areas of the brain, taste receptors are not uniquely expressed on taste buds and the ____ ____ of taste buds for primary tastes link to a ____ area of the brain.
- entire set
- single
Vision arises from signaling initiating in ____ and ____ ____ of the eye. Rod cells (____ ____, but not distinct for ____) contain the pigment ____, which consists of a 7TM protein called ____ linked to a vitamin A derivative called ____ (linked via a ____ bond).
- rod and cone cells
- sense light
- color
- rhodospsin
- opsin
- retinal
- lysine
Retinal is light sensitive and can flip between the ____ form and the __-____ form when exposed to light. This slight change in structure of retinal also changes the ____ protein, ultimately activating a vision-related G protein called ____.
- 11-cis
- all-trans
- rhodopsin
- transducin
Transducin binds ____ when ____ and this causes transducin to activate a specific ________ to break down ____ to ____. Lowering cGMP concentration causes a ____ ion channel to stop the movement of ions into the cell, ____ the nerve signal.
- GTP
- active
- phosphodiesterase
- cGMP to GMP
- cation
- starting
