Chemical senses

What are the three important things of taste and smell

prepares the body for digestion, contributes to the ‘flavour’ of food, are strongly connected to memory

What is the gatekeeper function for taste

identifies what the body needs for survival and detects substances that are damaging to the body

What are the four basic tastes

salty, sour, sweet, bitter

Give a reason why food can taste salty

because of sodium chloride

Give a reason why food can taste sour

hydrochloric acid

Give a reason why food can taste sweet

sucrose

Give a reason why food can taste bitter

quince

Give a reason of the taste of umami

the meaty taste is associated with monosodium glutamate

What does the tongue contain

papillae

What are the different shapes of papillae

filform, fungiform, foliate, circumvallate

What shape is filiform papillae

cone shape

What shape is fungiform papillae

mushroom shape

What shape is foliate papillae

folds

What shape is circumvallate papillae

flat-mounds shape

All papillae contain taste bunds except for ….

filiform

What part of the tongue has no taste sensation when stimulated

the centre

How many taste cells does each bud contain

50-100

What is the taste system structures

1. fungiform papilla

2. taste bud

3. taste cell

4. receptor

Information processed in the taste buds is relayed to different fibres from three cranial nerves, what are those three cranial nerve

the facial nerve, the glossopharyngeal nerve, the vagus nerve

What parts of the brain are considered to be the primary taste cortical areas

the insula and the frontal operculum

Humans are microsmatic meaning

smell is not crucial to survival

Why are animals microsmatic

it helps them orientate themselves, marks territory, guides to specific locations or food, pheromones

Molecules with a similar structure can …

smell very different

Molecules with very different structures can …

smell very similar

Some odours are made up of …

numerous different molecules

What do detection thresholds depend on

compounds

Each olfactory receptor is ….

specific to a narrow range of chemicals meaning that signals are transmitted to the glomerulus and are then sent to higher cortical areas

Different odorant’s can cause …

different patterns of activation

Different features of molecules are represented by …

different regions on the olfactory bulb (e.g. longer carbon chains activate receptors further left)

What is the chemotopic map

it is the map of odorant’s in the olfactory bulb

What is the brain pathway

Olfactory bulb to piriform cortex then to the orbitofrontal cortex then to the amygdala which is linked to emotion

What is a odour object

it is the ability to categorise an odour even though composition can differ greatly

What is the piriform cortex

it participates in the formation of odour objects by a process of pattern completion

What is flavour

it is taste and smell

What is retronasal olfaction

odorant molecules in the oral cavity and the pharynx reaching olfactory mucosa

Orthonasal olfaction is via

the nose

Where is the first area where smell and taste signals meet

the orbitofrontal cortex

Why is the orbitofrontal cortex suggested as a centre for processing flavour

presence of bimodal neurons and neurons that respond to congruent qualities in different modalities

What are bimodal neurons

neurons responding to more than one sense (e.g. tastes and smell, or taste and vision)

Give an example to what it means when neurons respond to congruent qualities in different modalities

sweet smell and sweet taste