# Your Sense of Smell: How Do The Recpetors "Recycle"?

**URL:** <https://boards.straightdope.com/t/your-sense-of-smell-how-do-the-recpetors-recycle/554877>\
**Category:** Factual Questions\
**Created:** [September 24, 2010, 2:40pm UTC](https://boards.straightdope.com/t/your-sense-of-smell-how-do-the-recpetors-recycle/554877 "2010-09-24T14:40:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\
**Post date:** [September 24, 2010, 2:40pm UTC](https://boards.straightdope.com/t/your-sense-of-smell-how-do-the-recpetors-recycle/554877/1 "2010-09-24T14:40:11Z")

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In my very limited understanding, you are able to perceive smells because the molecules causing the smell fit into positions on the surface of receptor cells, much as a key fits into a lock. This in turn, generated a nerve impulse, which is sent to the brain.  
My question: how long do the receptor cells keep the smell molecules locked in? How exactly are they discarded? Take the example of smelling something nastly (like decaying flesh)-you instinctively run away from such a smell. yet, the smell seems to stay with you for a long time-while the smell of a nice flower might last only seconds-why?