Teddies Talks Biology Issue 3

The Science of Smelling Huda Khalaf – L6th

The first sense activated when you are born; smell is a very powerful tool which influences people’s emotions and has the ability to transport you to a memory or give you a feel- ing. Smell is the most sensitive of the senses. People can remember smells with 65% accu- racy after a year, while visual recall is only about 50% after three months. But how is the body able to translate

Here, the cells have cilia which are covered by the mucus of the nasal cavity, facilitating the de- tection of and response to odour molecules by olfactory receptors. No one knows what actually causes olfactory receptors to react – there are many theories surrounding this, ranging from the chemical molecule’s shape to molecular vibra- tion. The electrical activity produced in these hair

cells is then transmitted to the olfactory bulb followed by the olfactory tract. The olfactory tract trans- mits the signals to the brain to areas such as the olfac- tory cortex, hippocampus, amygdala, and hypothala- mus. Many of these areas of the brain are a part of the limbic system. This is the system of the body which is involved with emo- tional behaviour and memory. That is why when

the detection of a chemical molecule into a specific scent? In order to be percep- tible by our noses, chemicals need to be small and volatile. Fragrant molecules escape from their fluid or even solid state in- to the air and are de- tected by our sensory tissue, called the ol- factory epithelium.

This is a mucous membrane which lies on the roof of the nasal cavity, in humans, it is ap- proximately 9cm2 in size and 7cm above and behind the nostrils. Odorants reach this area in the air we breathe; if something smells very faint, we sniff two or three more times, forcing more air and fragrance towards the olfactory epithelium.

you smell something, it often brings back memo- ries associated with that specific object. This al- so helps us recognise substances which are hid- den (such as when entering a house and know- ing that a cake is in the oven) or helps us classify a scent as unknown (such as when you go to an exotic restaurant for the first time).

Issue 3 | Teddies Talks Biology

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