⊛ learn · lesson 10

how smell works

from the air to the brain

two ways in.

breathe in, and scent molecules go up through your nostrils. eat, and they rise from your mouth through the back of your throat. both reach the same patch of tissue, high in the nose.

the path to the brain.

tap each stop.

a nobel for the nose.

in 1991, linda buck and richard axel described a huge family of genes, first found in rats, that looked like the code for smell receptors. in 2004 they shared the nobel prize in physiology or medicine.

a pattern, not a lock.

humans have several hundred working smell receptor genes. in mice, one molecule woke several receptors, and one receptor answered to several molecules. different smells made different patterns.

why you stop smelling your own perfume.

stay with a smell and it seems to get weaker, even if nothing has changed. scientists study this as adaptation, and they are still working out where in the system it happens.

true or not?

tap each one.

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