uoft psl300 smell and taste (cns and senses lecture 8 smell
and taste) Questions With Complete Solutions
receptor cells and odourant
- each receptor cells has many copies of one kind of odourant
receptor molecule on its membrane
- have about 400 kinds of receptor cells (primary odours)
GPCRs in olfactory receptor cells
- odourant molecule binds its receptor
- activates Golf
- increases local concentration of cAMP
- cAMP gated cation channels open
- depolarize receptor neurons
- trigger AP along cells axon to olfactory bulb in brain
sensitivity of receptor cells
- can detect a single molecule of preferred chemical
- about 40 cells must react before we consciously experience a
smell though
pinocytosis
- continually endocytose fluid
- olfactory receptor cells are pinocytotic and send this fluid
along the nerves into the brain
life span of olfactory receptor cells
, - short lived
- degenerate after a month or two
- replaced by new ones (unusual for neurons to be replaced)
cribriform plate
- olfactory receptor cells send their axons into the brain through
tiny holes in the cribriform place
- bone at the base of the cranial cavity
olfactory bulb
- extension of the cerebrum
- lies on the underside of the frontal lobes
- receptor cells project to here
- projects to olfactory cortex and limbic system
olfactory nerve
- cranial nerve 1
- projection from the receptors to the bulb
convergence of olfactory neurons
- many receptor cells converge on each olfactory nerve bulb
- enhances sensitivity but discards spatial information
olfactory cortex
- bulb projects to olfactory cortex
- bypasses the thalamus
- in the frontal and temporal lobes
limbic system and smell
and taste) Questions With Complete Solutions
receptor cells and odourant
- each receptor cells has many copies of one kind of odourant
receptor molecule on its membrane
- have about 400 kinds of receptor cells (primary odours)
GPCRs in olfactory receptor cells
- odourant molecule binds its receptor
- activates Golf
- increases local concentration of cAMP
- cAMP gated cation channels open
- depolarize receptor neurons
- trigger AP along cells axon to olfactory bulb in brain
sensitivity of receptor cells
- can detect a single molecule of preferred chemical
- about 40 cells must react before we consciously experience a
smell though
pinocytosis
- continually endocytose fluid
- olfactory receptor cells are pinocytotic and send this fluid
along the nerves into the brain
life span of olfactory receptor cells
, - short lived
- degenerate after a month or two
- replaced by new ones (unusual for neurons to be replaced)
cribriform plate
- olfactory receptor cells send their axons into the brain through
tiny holes in the cribriform place
- bone at the base of the cranial cavity
olfactory bulb
- extension of the cerebrum
- lies on the underside of the frontal lobes
- receptor cells project to here
- projects to olfactory cortex and limbic system
olfactory nerve
- cranial nerve 1
- projection from the receptors to the bulb
convergence of olfactory neurons
- many receptor cells converge on each olfactory nerve bulb
- enhances sensitivity but discards spatial information
olfactory cortex
- bulb projects to olfactory cortex
- bypasses the thalamus
- in the frontal and temporal lobes
limbic system and smell
