chemical receptors - olfaction Flashcards
where are olfactory receptors cells (chemoreceptors) found?
roof of the nasal cavity in the olfactory epithelium
smell…major/minor
minor sense
where are odorant receptors (olfactory receptors)?
on hair projection from receptor cells
receptor cell axons project to…..
mitral cells in the olfactory bulb
olfactory transduction
- odorants bind to chemoreceptors
- receptor cells are activated and axons
- axons send electrical signals to MITRAL CELLS (signals relayed in glomeruli)
- mitral cells connect directly to primary olfactory cortex and the amygdala
no thalamic relay
what is responsible for tingling, burning, coolness sensation
free nerve endings
selectivity in olfaction?
receptors are ‘tuned’ to particular odorant chemicals
adaptation in olfaction
responses fall rapidly after prolonged odorant exposure
mitral cells connect direction to….
primary olfactory cortex and amygdala
there is no thalamic relay
explain he strong emotional impact of smell
direct connection to amygdala
population coding
we can smell ~10000 odours. not a receptor for each odour, depends on PATTERN OF FIRING across receptors/mitral cells
olfaction; analysis or synthesis?
synthetic nature of olfaction: receptor outputs grouped, ability to recognise odours
where are free nerve endings
in the Mucosa
more or less smells per mitral cells
number of smells humans can recognise outnumbers the number of types of mitral cells
olfaction and memory
only sense with direct projections between the primary sensory cortex and the amygdala
