Smell Flashcards
Smell stimuli
Chemicals / odours
What are olfactory nerve fibres an extension of?
The forebrain - sensory system
Afferent nerve fibres sit where?
roof of nasal cavity to olfactory bulb
Olfactory signal transduction occurs where?
Ends of olfactory receptor cell cilia
How does olfactory signal transduction start?
Diffusion of odourant molecules through and odourant receptor
How many different cell receptor types do we have?
1000
How many different smells can we detect?
10,000 - 50,000
What percent of the smells we perceive are pleasant?
20%
How can we detect 10,000 different smells with only 1000 smell receptors?
Odours bind to a few different receptor types (strongly and weakly) and will mix to create different smells and we can determine how good the smell is
Anosmnia and cause
Partial or complete loss of smell
- caused by swelling or blockage in the nose, but can also be due to brain or nerve damage
Anosmia and COVID
COVID invades the supporting cells around the olfactory receptor cells and they cant support the olfactory cells
How do odourants depolarise neurons
Diffuse into mucus and bind to receptors on the axon terminals
