9. SMELL Flashcards
1
Q
- What is anosmia?
A
- it is the partial or complete loss of sense of smell
- this also affects most of the ability to taste
2
Q
- What can cause anosmia?
A
- head trauma
- respiratory infections
- aging
3
Q
- What is the function of sensory cells?
A
- they translate electromagnetic, chemical and mechanical stimuli into action potentials
- our nervous system then makes sense of these translations
4
Q
- What is transduction?
A
- it is the action or process of converting something (especially energy) or a message into another form
5
Q
- What is another term for taste?
A
- gustation
6
Q
- What is another term for smell?
A
- olfaction
7
Q
- Which receptors are smell and taste dependent on?
What do they detect?
A
- they are dependent on chemoreceptors
- these are found in the taste buds and the nasal passages
- they detect molecules of food
- they detect the air around us
8
Q
- When are our chemical senses sharpest?
A
- they are sharpest right at birth
- they are what allows newborns to orient themselves chiefly by smell
9
Q
- What are taste and smell powerful at doing?
A
- they can activate memories
- they can trigger emotions
- they can alert us of danger
- this is seen with PTSD and Depression cases
10
Q
- What is necessary in order to smell something?
A
- the odourant must be volatile
(easily evaporated) - or it must be in a gaseous form
- this is so that it can be absorbed by the nostrils
11
Q
- What happens when a person sniffs harder and deeper?
A
- they absorb more molecules from their surroundings
- the smell is felt more
12
Q
- What filters out the molecules that enter the nasal cavity?
A
- the protective nose hairs that catch them
13
Q
- What do these nose hairs prevent?
A
- they prevent many molecules from making it all the way to the back of the nose
- and hitting the olfactory epithelium
14
Q
- What is the Olfactory Epithelium?
A
- it is the Olfactory system’s main organ
- it is a small, yellowish patch of tissue
15
Q
- Where is the Olfactory Epithelium located?
A
- it is located on the roof of the nasal cavity
16
Q
- What does the Olfactory Epithelium contain?
A
- it contains millions of olfactory sensory neurons
- these are bowling pin shaped
- they are surrounded by insulating columnar supporting cells
17
Q
- Where do the airborne molecules of any food end up?
A
- they end up on the olfactory epithelium
18
Q
- What happens to the airborne molecules after they end up on the Olfactory Epithelium?
A
- they dissolve in the mucus that coats the olfactory epithelium
19
Q
- What happens once the airborne molecules are in the mucus coating of the olfactory epithelium?
A
- they are able to bind to the receptors
- these receptors are located on the olfactory sensory neurons
20
Q
- What happens when the receptors on the olfactory sensory neurons hit their necessary threshold?
A
- they fire action potentials up their long axons
- these action potentials go through the ethmoid bone
- the ethmoid bone is located in the olfactory bulb
- this is in the brain
21
Q
- Are olfactory neurons specialised?
How so?
A
- olfactory neurons are specialised
- they have receptors for just one kind of smell
22
Q
- What happens after each smell-specific neuron is triggered?
A
- the signal travels down its axon
- this is where it converges with other cells
23
Q
- In which structure does the signal and the other cells converge?
A
- in the glomerulus
- LATIN= this means ball of yarn
24
Q
- What is the glomerulus?
A
- it is a tangle of fibres
- it serves as a transfer station
- this is where the nasal information turns into brain
information
25
Q
- What happens inside the glomerulus?
A
- the olfactory axons meet up with dendrites of a mitral cell
- a mitral cell is another kind of nerve cell
26
Q
- What is present for each mitral cell?
A
- there are any number of olfactory axons synapsing with it
- they each represent and identify a single volatile chemical
27
Q
- What is the combination of the mitral cell and the olfactory neuron responsible for?
A
- it detects a specific smell
28
Q
- What happens after the mitral cell picks up its signal from an olfactory neuron?
A
- it sends this signal along the olfactory tract
- this signal is sent to the olfactory cortex of the brain
- the smell then hits the brain through two avenues
29
Q
- What are the two avenues through which smells hits the brain?
A
- the one brings data to the frontal lobe
- this is where it can be consciously identified
- the other pathway heads straight for the hypothalamus,
the amygdala and other parts of the limbic system - this is known as the emotional pathway
30
Q
- What are the attributes of the emotional pathway?
A
- it is fast, intense and quick to trigger memories
- if the odour is associated with something dangerous
- it quickly activates your sympathetic system’s flight or
fight response
31
Q
- Why can anosmia pose many problems?
A
- without smell:
- you can not access emotional memories associated
with particular smells
- you can not sniff out dangers in your environment
