Zusammenfassung der Ressource
Taste and Smell
- Taste
- 5 basic tastes
- Umami
- Sweet
- Bitter
- Sour
- Salt
- Taste buds
- Create neural signals
- Sent via cranial nerves
- Embedded in papillae
- Contain taste receptor cells
- Coding of taste quality
- Labelled lines
- Each taste fibre carries a particular taste quality?
- Patterns of activity across different taste neurons?
- Examples of both in other senses
- Genetic variation
- Arthur Fox (1931)
- Dennis Drayna (2003)
- Supertasters
- Different genes for PROP receptors
- More taste buds
- Hardwired taste preferences
- Evidence from babies
- People can be desensitised to chilli peppers
- Only humans eat it!
- Smell
- Smelly molecules
- Small
- Volatile
- Hydrophobic
- Physiology
- Air flow through nose disrupted by turbinates
- Contacts with olfactory epithelium which odourants stick to
- Nose has a cycle time of three hours during which different
nostrils have different flow rates and smell different things
- Anosmia
- Cribiform plate moved backwards (usually because something has hit you in the front of your face)
- Odours bind to olfactory cilia
- Part of the OSN
- Each OSN has a single type of odour receptor
- 5 million of these!
- Fire once 8 binding sites are filled
- Sends to olfactory bulb (not thalamus)
- Lock and key model
- But it is difficult to predict smell from shape...
- Vibrational sensitivity?
- 300 receptor types
- Generate patterns of activity in entorhinal and piriform cortices
- Associate code pattern with object
- Human pheromones?
- VNO
- Doesn't function in adult humans (but it does in foetuses)
- HLA
- MHC is present in humans as a result of this gene complex
- Androstadienone
- Metabolite of testosterone
- Blindsmell
- Brain response to concentrations below perceptual threshold?
- Smell of tears
- Chemosignal