 Specialized
receptor cellsof the
olfactory epitheliumdetect and recognize smells.
Your nose is a huge cavity built to smell, moisten, and filter the air you breathe. When you breathe in, the tiny hairs, called
cilia, act like a broom and filter everything trying to get into your nose; from
dust particlesto bugs.
The air passes through the
nasal cavityand though a thick layer of
mucous membraneto the
olfactory bulb. The smells are recognized here because each
smell moleculefits into a nerve cell like a puzzle piece. The cells then send signals to the brain via the
olfactory nerve. The brain then interprets those molecules as the sweet flowers, or the curdling milk that you've held up to your nose.
Humans can detect over 10,000 different smells. The olfactory nerve picks up the scents from the air you breathe and translate them into nerve impulses or messages that are then sent to the olfactory bulb located in the front of the brain.
Actually, how and why we smell is still inadequately known. There are many theories about the exact process of our sense of smell. Most believe that it is highly specialized processes in which
molecular ringsand receptors invite odorant-bringing proteins. It is a very complicate, intricately detailed, and mysteriously misunderstood system, our sense of smell.
Did you know?
Dogs have 1 million smell cells per nostril, and their cells are up to 100 times larger than those of humans.
Anosmiais the condition that makes people unable to smell.
Your sense of smell directly affects your sense of taste.
Smell can evoke emotions such as happiness, fear, even sexuality.
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note:
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receptor cells: 感受細胞
olfactory epithelium: 嗅覺上皮細胞
cilia: 纖毛
dust particle: 塵粒、微塵
nasal cavity: 鼻腔
mucous membrane: 粘膜
olfactory bulb: 嗅球（嗅葉的球莖狀末
梢，嗅覺神經的起步）
smell molecule: 嗅覺分子
olfactory nerve: 嗅神經
Anosmia: 嗅覺缺失癥
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