Olfaction Flashcards
anosmia
total loss of smell
What is the sense of smell called?
Olfaction
Olfaction is a critical sensory system involved in detecting airborne chemicals.
What are the two ways the sense of olfaction can be stimulated?
- O_____- nasal: odours inhaled through the nose
- R_____-nasal: occurs when odorants travel from the mouth to the olfactory receptors
O_____-nasal refers to the direct inhalation of scents, while R_____-nasal relates to the retro-nasal perception during eating.
What is the first step in the olfactory pathway?
Odor molecules enter the nasal cavity and dissolve in the mucus layer of the nasal epithelium
This step is crucial for the detection of smells.
What happens when an odorant binds to an olfactory receptor?
It triggers a biochemical reaction that generates an electrical signal in the receptor cell
This process is essential for transmitting olfactory information to the brain.
What is the role of the olfactory bulb?
Processes electrical signals and relays them to the glomeruli
The olfactory bulb is a key structure for organizing scent information.
Which brain areas receive processed olfactory signals?
- Olfactory cortex
- Amygdala
- Hippocampus
- Thalamus
- Insula
These areas are involved in various aspects of smell processing, emotion, and memory.
What is the olfactory epithelium?
Part of the mucosa that lines the nasal cavity, responsible for detecting odours
The olfactory epithelium contains sensory receptors for smell.
How long is the lifespan of olfactory receptor cells?
1 month
These cells are continuously replaced in the nasal cavity.
What is the primary olfactory cortex called?
Piriform cortex (PC)
The PC plays a key role in processing olfactory information.
What is olfactory acuity?
A person’s ability to discriminate between odours
This ability varies across different types of smells.
What is short term adaptation in olfaction?
Decrease in responsiveness under conditions of constant stimulation
It leads to a rapid loss of odour intensity.
What is anosmia?
Total loss of smell
It is diagnosed when an individual deviates significantly from the population mean.
What is parosmia?
A change in normal perception of smell
It can cause good smells to be perceived as unpleasant.
What does the term ‘olfactory liking’ refer to?
Individual differences in the preference for certain smells
For example, some people find coriander unpleasant due to specific olfactory receptors.
What is the Proustian effect?
Odour memories evoke emotional, autobiographical memories
This phenomenon illustrates the strong link between smell and memory.
What is the olfactory threshold?
Lowest concentration of a chemical in air that people can detect
This varies among individuals and substances.
What does the term ‘population coding’ refer to in olfaction?
Odour detection is represented by the overall activity across a population of neurons
This suggests that multiple neurons work together to identify smells.
What are pheromones thought to involve?
The vomeronasal organ (VNO)
located just above the roof of the mouth
In humans, the VNO is considered vestigial and likely has lost its functional role.
True or False: Humans have a larger olfactory bulb compared to dogs.
False
Humans have a smaller olfactory bulb compared to many mammals.
What is the role of the hippocampus in olfaction?
Helps in forming odour-associated memories
The hippocampus is crucial for memory processing related to smells.
Fill in the blank: The _______ is a structure in the brain that links odour to emotion and memories.
Amygdala
The amygdala plays a significant role in emotional responses to smells.
hyposmia
reduced sense of smell
parosmia
unpleasant sense of smell - change in perception
phantosmia
presence of smell when smell isn’t there
specific anosmia
some people unable to detect families of similar smell compounds