Page 21 - #57 English

All scents we have sensed since birth have con-
tributed to the construction and consummation of
the memory bank of our olfactory sensation. During
summer in childhood, blended odors of salty water
left in hair after swimming, orange soda together
with streets shaded by luxuriant trees constitute our
memory of summer. After growing up, if we smell the
When smelling the scent of apple, scent of salty water, leaves and orange soda again, the
memory of childhood summer will revive. Otherwise,
we expect to see an apple.. if grandma once cooked a super delicious braised pork,
we would probably expect the same taste again every
However, it is also likely to come out from anoth- time we sensed that smell (though tastes could be dif-
er object with apple fragrance. Cosmetics companies ferent in spite of the similar scent). Olfaction is the
always make huge efforts to add pleasant scents into deception, guidance and supplementary to sensation.
their products. For example, coconut flavored sham- Pleasant scents can make our sensation quite joyful.
poo can function as relaxant by reminding people of Similarly, disgusting odors can also bring us unpleas-
things such as beach, tropical region, holiday, etc. ant experiences .

Physical conditions that
completes
olfaction:

● Volatile odor molecules
● Propagation medium
(mainly refers to air)
● Nose
● Olfactory nerves
● Olfactory memories

None of the above conditions is dispensable. Firstly, of volatile aromatic components. When pressing oranges,
odor molecules of a compound (volatile) evaporate into people are able to sense citrus aromatic scent distantly.
the air, after which our nose captures these molecules. However, it is harder to discern some other compounds
The molecules then travel across the mucus of nasal cavity from their smell. For example, people can hardly rely only
and interact with the olfactory cells at the top of our nose. on olfaction to sense the existence of pure water without
Olfactory nerves now start to transmit sensations to those their eyes open. That is because there are almost no vola-
odor molecules to the brain. Finally, the brain will pair up tile aromatic compounds present in pure water. Secondly,
the captured odors with the existing olfactory memories propagation medium’s mobility also has an impact. When
so as to determine the smell we have just sensed. As seen, wind blows, it accelerates molecules’ propagation and thus
though olfaction and audition are both remote sensation, makes it easier to smell distant odors. Nose also plays a
they differ in nature: auditory sensation does not originate role: if somebody unfortunately catches a cold, mucus
from a specific compound whereas olfactory sensation is the inside his nose will get thicker, making it difficult for
transmitted from odor molecules of a real existing matter. odor molecules to pass through and hence harder for us
The acuity and preciseness of olfaction depend on the fol- to smell any odor. Also,after olfactory nerves transmit our
lowing variables. For example, the first variable is volatile odor sensation to the brain, it fails to match up with our
odor molecules. Some compounds contain a large amount olfactory memories, we still cannot discern those odors.

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