Chemical Senses (3) Flashcards
what are the chemical senses
taste (gustation) and smell (olfaction)
what are the five different taste qualities in humans
saltiness, sweetness, sourness, bitterness, umami(protein)
where are taste receptors located
on the tongue; substances must be dissolved in saliva to stimulate taste receptors on the tongue
how many taste receptors are on a taste bud and how are they organized
50-150 taste receptors on one taste bud
organized in orange like segments
true or false: most taste receptors will respond to more than one chemical
true
how is taste transduction obtained in taste receptor cells
the specifically sensitive taste cells will cause Na+ to come into the cell, depolarizing the cell
describe the gustatory pathway to the brain!!
- mouth
- afferents
- LGN
- VPM (ventral posterior medial of thalamus)
- primary gustatory cortex
where are the olfactory receptors located
olfactory epithelium (dorsal part of nose)
how many different types of olfactory receptors are there in a human
ONE
how are olfactory receptors organized
olfactory receptor cell body is in the nose, the cilia is in the mucus layer, and the axons from the olfactory neurons form the olfactory nerve (cranial nerve 1)
describe olfactory transduction
- odorant molecules bind to g-protein coupled receptors
- the amount of second messenger (cAMP) that is produced changes
- increase of cAMP opens ion channels (Cl- channels open)
- cell is depolarized
- if enough depolarization occurs, the signaling will go to the olfactory bulb
describe the olfactory pathway!!
- olfactory cells
- olfactory nerve
- olfactory bulb
- cortical structures
* bypasses the thalamus
how are glomeruli organized in the olfactory bulb
glomerulus received axons from ~25000 olfactory cells and synapses with mitral cells (carry info from receptors to brain)
where does the perception of flavor take place
orbitofrontal cortex (secondary gustatory cortex)
