Tag: smell

Best of 2014

Credit - Ltikorea CC-BY-SA

Credit – Ltikorea CC-BY-SA

Leaving out the home, contact, downloads and welcome pages, these posts are the best of 2014 by visit.

14. Near Death Experience – Part Three
What happened to parts One and Two? How does the third one outrank the others?

13. Flesch Reading Ease
This surprises me. Why is there so much interest in a method for rating how easy it is to read text?

12. Yawning
Of things our bodies do, including Synesthesia, Smell (1, 2 & 3), Earworms and Handedness, yawning is the most popular.

11. Ball Lightning – Part Three
Again part three is first.

10. Ball Lightning
And it appears readers jumped right over Part Two to read these.

9. BitTorrent Bundles
Good. I’m glad people are interested in my BitTorrent Bundle. No idea how this fits in with the rest, though.

8. Gecko Feet
I’m glad to see this. I have a soft spot for these little guys.

7. Altocumulus Castellanus
This is the only entry from the Cloud of the Day series. Maybe because it sounds so grand?

6. Collective Nouns
I like this series. It’s a lot of fun. Even Part Two.

5. Aquatic Ape – The Theory Evolves
The Bipedal series did well, taking three of the top five spots.

4. Whispering Galleries
This is no surprise. There’s something intrinsically interesting about whispering galleries.

3. Spanking for Love
This is no surprise either. Humans, eh?

2. Bipedal – The Aquatic Ape Theory
The Aquatic Ape is popular, but the Savanna Ape is even more so.

1. Bipedal – The Savanna Theory
This post got more than twice the number of views of the two Aquatic Ape posts combined.

That’s what you were looking at in 2014. Thank you for your interest, and thank you for keeping it interesting for me. Without you, it could be a pretty bleak job maintaining Green Comet’s home on the Internet. You encourage me to carry on, both with this site and with the sequel to the novel, which should be ready in the middle of 2015.

That was the best of 2014. See you in the new year.

rjb

Taste

Photo credit - Kimli

Photo credit – Kimli

The sense of taste is much simpler than the sense of smell. Whereas we can distinguish thousands of different smells, there are only four (or six, as will be seen later) basic tastes. The four are sweet, sour, salty and bitter, each identified by a class of taste buds on the tongue and the roof of the mouth.

Sweetness is detected primarily near the tip of the tongue. Those taste buds can detect the shape of the hydroxyl groups found in sugar molecules. Sour receptors along the sides of the tongue respond to the acids in sour substances. Salt receptors, also along the edges, detect the metal ions, such as sodium, in salts. Complex nitrogen-containing compounds called alkaloids are detected as bitterness at the back of the tongue.

Sweetness tells us if the fruit or vegetable is ripe. Sourness might put us off unripe fruit or food that is going bad. Saltiness alerts us to the presence of chemicals that are essential to the proper functioning of our cells. Alkaloids are often poisonous. Their bitter taste is our warning. Basic survival depends on the four basic tastes.

There’s more to taste than that, though. There is the vast array of flavors we can identify when we combine tastes with smells. And there is actually a fifth category of taste called “umami.” Umami is the sensation stimulated by the presence of glutamate. Glutamate is the most common amino acid, accounting for almost half of the protein in plants and almost one fifth of animal protein. Proteins are made from amino acids. Although we can’t taste proteins themselves, we can taste their constituent amino acids as they start to break down in our mouths. Being able to detect the presence of such essential food elements is a pretty obvious benefit.

With the five basic tastes, alone or together, combined with thousands of smells into a huge catalog of flavors, we humans can have a very rich relationship with food. Throw in texture, or “mouth feel,” like smooth or creamy and so on, along with the recent discovery that we can taste fat, and a person could spend their whole life just trying new food sensations.

At this time of year it’s good to have good taste. We have turkey, shortbread, oranges, chocolate and so on in an endless stream of intoxicating seductions. Chewing a shortbread cookie sets off a burst of activity. The sugar activates the front of the tongue, where sweetness receptors abound. Salt stimulates the sides. Protein arouses umami. Vapors rise up the back of the nose where they engage the sense of smell. Along with the evolving chemical combinations in the mouth and nose, there exists the mechanical world of mouth feel. The crumbling and dissolving. The smoothness of fat. It all combines to make you want to swallow so you can take another bite.

The sense of taste is simply profound.

rjb

Smell – Part Three

Nose of a Dog
See also parts one and two.

It’s well accepted now that we, humans and many other species, communicate by the sense of smell. There’s no language involved, except in the broadest sense. We can talk about the language of smell in an abstract way, but a linguist wouldn’t call it that. They wouldn’t find the identifiable structures, like word ordering and syntax, that a real language needs. For the rest of us, who aren’t sure what “syntax” means, really, the metaphor of language can be fitted quite comfortably to smell-based communication.

Smell – Part Two

Nose of a Bear
See also parts one and three.

There’s more to smell than detecting odors. If it was just a case of identifying odors, it wouldn’t be very interesting for very long.

Our ability to smell has been broken down to seven primary odors. Those are: camphoric – like mothballs, etheral – like cleaning fluid, floral – flowers, musky – some perfumes, pungent – like vinegar, peppermint – mints and putrid – like rotting eggs. Of course, we actually recognize thousands of different smells. And even with the primary odors there are wide variations. Most of us can think of other putrid smells besides rotten eggs, for instance.

Smell

Human nose
See also parts two and three.

Not everyone smells the same. It seems to be true that every human has their own bouquet, other than identical twins. Even dogs can’t tell identical twins apart by smell, and dogs smell far better than humans. Maybe in both senses of the word. How would we know? We don’t smell especially well.

We smell well enough to survive and thrive in our environmental niche, and no more. Our bodies by nature don’t waste their finite resources where they’re not needed. The proteins deployed in the sensory system, and the neurons used to process the subsequent sensory information can be used elsewhere. Still, on average, we are estimated to be able to discriminate about 10,000 different odors.

Smells are chemicals. They are distinct arrangements of molecules; particles with particular shapes and distinct modes of vibration. The particles have to be small enough to float in the air, so we can breathe them into our noses. Then we dissolve them in the mucus lining our olfactory tissue in the region called the nasal mucosa. Humans have about ten million receptor cells, which have a stem tipped by a knob that has hairs. The actual smell receptors are on the tiny hairs.

Each receptor is attended by a neuron, whose job is to send a signal to the brain when a smell particle is identified. Although we have hundreds of different kinds of odor receptors, for identifying hundreds of molecules, only a few kinds are on each hair. The types, numbers and distribution of receptors vary through the population. We don’t all smell the same.

Smell has the shortest path to the brain of all the senses. The information goes directly into the limbic system, a most ancient part of the brain. The limbic system is strongly involved in basic motivation, emotions and memory. This region has a rich network of connections with other parts of the brain, going both ways.

Not all smells are passed on to the brain. Some we simply can’t detect, not having the required receptor. Sometimes the neuron doesn’t fire, if the system is saturated by that smell, for instance. Not all smells are passed to our awareness if the limbic system decides it’s not necessary. So a lot of the smells that we react to, we don’t even notice.

We all have a different smell. Likewise, we all have a different sense of smell. Not everyone smells the same.

rjb

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