3.2 taste

papillae

increases surface area on tongue

3 kinds of papillae

1. circumvallate

2. foliate

3. fungiform

circumvallate

back 1/3 of the tongue

foliate

sides of tongue

fungiform

front 2/3 of tongue

taste buds

are embedded within papillae and contain taste receptor cells

tastants

specific chemical molecules found on food that activate taste receptors when they come into contact

5 basic tastes

1. sweet

2. salty

3. sour

4. bitter

5. umami

chemoreceptors

sensory receptor proteins that detect chemical stimuli and covert them into neural signals

sensory pathway for taste

1. substances dissolve in saliva

2. tastants in saliva activate taste receptor cells

3. taste cells covert chemical input into electrical signal

4. signal is transmitted to cranial nerves

5. cranial nerves send info to brain so taste is perceived

CNS pathway for taste

1. cranial nerves recieve signal

2. CN synapses at brainstem

3. info sent to thalamus

4. then the insula

sweet

metabotropic, detected by T1R2 + T1R3

salty

ionotropic, uses Na+ and Cl- channels

sour

ionotropic, believed to have an ion channel where H+ ions released in acidic foods acts on

bitter

metabotropic, T2R receptor

why are humans highly sensitive to bitter foods?

evolvution to detect poisons

umami

metabotropic, detected by T1R1 + T1R3, glutamate receptor (MSG)

orthonasal

smell through nostrils

retronasal

smell through back of nose

what role does olfaction play in flavor perception?

when eating, compounds from food travel up the throat to the nose, stimulating olfactory receptors and adding complexity to flavor