Olfaction

Weekly Wrap Volume 147

This is a weekly wrap of our popular Daily Knowledge Newsletter. You can get that newsletter for free here.

great-white-shark

While sharks aren’t exactly the ruthless predators most Hollywood features make them out to be (see: Do Sharks Really Not Like How Humans Taste?), they do possess a number of frighteningly efficient mechanisms to assist with aquatic hunting, including ultra-streamlined bodies, high intelligence, the ability to detect electrical fields and minute changes in water pressure, great hearing, incredibly sharp vision, amazing sense of smell (Lemon sharks can even detect tuna oil at a concentration of just one part per 25 million), and the topic of today- many rows of razor sharp teeth, including the ability to rapidly replace them. But are sharks actually able to grow an unlimited number of teeth…(more)

cleaning-wound-hydrogen-peroxide

As a child, did you ever skin your knee and fear telling your parents, afraid of your mom breaking out the brown bottle of pain containing hydrogen peroxide to “help heal” your wound? Given the agony it caused, you might have wondered whether the fizzing liquid was actually helping, and why hydrogen peroxide bubbles when it comes in contact with your skin. If you’re still wondering today, well, wonder no more. To begin with, hydrogen peroxide does indeed kill bacteria, viruses, fungi and a whole host of pathogens thanks to the fact that it is…(more)

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Bonus Quick Facts

  • Ever wonder why we call junk messages “spam”? Well, wonder no more. While some have suggested that this was because SPAM (as in the Hormel meat product) is sometimes satirized as “fake meat”, thus spam messages are “fake messages”, this potential origin, while plausible enough on the surface, is not correct based on surviving documented evidence of when the term started being used to mean junk or unsolicited messages. The real origin of the phrase comes from a 1970 Monty Python’s Flying Circus skit. In this skit, all the restaurant’s menu items devolve into SPAM. When the waitress repeats the word SPAM, a group of Vikings in the corner sing “SPAM, SPAM, SPAM, SPAM, SPAM, SPAM, SPAM, SPAM, lovely SPAM! Wonderful SPAM!”, drowning out other conversation, until they are finally told to shut it.
  • Two of history’s most influential figures, Abraham Lincoln and Charles Darwin, were born just hours apart from one another on February 12, 1809, though separated by the Atlantic, with Lincoln born in a one room cabin in Hardin County, Kentucky, and Darwin born in his family’s home in Shrewsbury, England. They also both lost their mothers at a very young age within about a year and a half of one another, Nancy Lincoln dying in 1818 and Susannah Darwin in 1817. While these two titans of history never met, they did share a common view on the institution of slavery, with Darwin noting in a letter in 1861, “Some few, & I am one, even wish to God, though at the loss of millions of lives, that the North would proclaim a crusade against Slavery. In the long run, a million horrid deaths would be amply repaid in the cause of humanity. What wonderful times we live in…. Great God how I should like to see that greatest curse on Earth Slavery abolished.”
  • In The Phantom Menace, Qui-Gon Jinn’s communicator is just…

Why Marijuana Gives You the “Munchies”

marijuana

If you’ve ever smoked marijuana, then you’ve probably had some experience watching all three Lord of the Rings movies while eating the most delicious steak you’ve ever had owing to the fact that you decided to cover it in peanut butter and jelly. It is at this point that you might find yourself wondering why marijuana gives you the munchies.

The answer appears to be a combination of a few different things, primarily an increase in your ability to smell, which in turn makes your food taste better; an upsurge in the release of a neurotransmitter, Dopamine; and through the complex mechanism of how the human body deals with hunger, the production of an appetite stimulating hormone ghrelin. So how does marijuana accomplish all this?

Marijuana, and its active ingredients, known as cannabinoids, affect the brain in a number of ways. For instance, the cannabinoid that gives us that memory-killing-high is Tetrahydrocannabinol (THC). There are at least 85 separate cannabinoids in marijuana, all exhibiting varied effects within the body. To better understand the role of these in feeling famished, let’s look at what normally stimulates our appetite.

The body uses several complex mechanisms to regulate hunger and subsequent feeding. Those mechanisms aren’t yet fully understood. However, what we do know is that hunger has been shown to be a two part mechanism that flip-flops when the body senses a decrease or excess in energy stores.

shutterstock_316922606

When it senses a deficit, it triggers the release of ghrelin. This hormone is released by the GI tract and stimulates your hypothalamus in the brain to increase hunger. Interestingly, it also affects an area of the brain known as the Ventral Tegmental Area (VTA), which helps in the release of the feel-good neurotransmitter dopamine.

Conversely, when there’s an excess in energy stores, fat cells release the hormone leptin. This stimulates the hypothalamus to inhibit hunger. Leptin has also been shown to affect the VTA, thus, also affecting dopamine release. Additionally, leptin counteracts the effects of another neurotransmitter, anandamide. Anandamide is another potent hunger stimulator that binds to the same receptor sites…

Why Marijuana Gives You the “Munchies”

marijuana

If you’ve ever smoked marijuana, then you’ve probably had some experience watching all three Lord of the Rings movies while eating the most delicious steak you’ve ever had owing to the fact that you decided to cover it in peanut butter and jelly. It is at this point that you might find yourself wondering why marijuana gives you the munchies.

The answer appears to be a combination of a few different things, primarily an increase in your ability to smell, which in turn makes your food taste better; an upsurge in the release of a neurotransmitter, Dopamine; and through the complex mechanism of how the human body deals with hunger, the production of an appetite stimulating hormone ghrelin. So how does marijuana accomplish all this?

Marijuana, and its active ingredients, known as cannabinoids, affect the brain in a number of ways. For instance, the cannabinoid that gives us that memory-killing-high is Tetrahydrocannabinol (THC). There are at least 85 separate cannabinoids in marijuana, all exhibiting varied effects within the body. To better understand the role of these in feeling famished, let’s look at what normally stimulates our appetite.

The body uses several complex mechanisms to regulate hunger and subsequent feeding. Those mechanisms aren’t yet fully understood. However, what we do know is that hunger has been shown to be a two part mechanism that flip-flops when the body senses a decrease or excess in energy stores.

shutterstock_316922606

When it senses a deficit, it triggers the release of ghrelin. This hormone is released by the GI tract and stimulates your hypothalamus in the brain to increase hunger. Interestingly, it also affects an area of the brain known as the Ventral Tegmental Area (VTA), which helps in the release of the feel-good neurotransmitter dopamine.

Conversely, when there’s an excess in energy stores, fat cells release the hormone leptin. This stimulates the hypothalamus to inhibit hunger. Leptin has also been shown to affect the VTA, thus, also affecting dopamine release. Additionally, leptin counteracts the effects of another neurotransmitter, anandamide. Anandamide is another potent hunger stimulator that binds to the same receptor…

Food smells better to sleepyheads

hamburger/bun

SAN FRANCISCO, Calif. — Foods may smell more appetizing when you’re tired.

Getting too little sleep seems to increase the brain’s sensitivity to food smells, a new study finds. This suggests sleep-deprived people might finds snacks more enticing. If true, this could help explain why people who burn the candle at both ends tend to eat more — and often weigh more.

Surabhi Bhutani is a nutrition scientist at Northwestern University’s Feinberg School of Medicine in Chicago. She shared her team’s new findings here on March 27 at the Cognitive Neuroscience Society’s annual meeting.

The group brought adults into their lab who had had slept only four hours the night before. Each inhaled a sequence of food odors. They might, for instance, include the scent of potato chips or cinnamon rolls….

Readers bugged by wine-spoiling stinkbugs

Stinkbugs accidentally harvested with grapes and fermented during the winemaking process release a pungent stress compound. It takes only three stinkbugs per grape cluster to ruin red wine’s taste, Elizabeth S. Eaton reported in “Red wine has stinkbug threshold” (SN: 3/18/17, p. 5).

“Does contamination of wine by the bugs’ stress compound pose any health risk to consumers?” asked Hal Heaton. “And does someone really count the number of stinkbugs on each of the huge number of grape bunches picked?”

The hormone emitted by stressed stinkbugs, (E)-2-decenal, is also found in cilantro, says Elizabeth Tomasino, a food scientist at Oregon State University in Corvallis who did the research. “It is actually found at much higher concentrations in cilantro than in wine and is not a health risk,” Tomasino says.

As for counting stinkbugs, there are people who count bugs on the vines, but not by bunch as the researchers did. “What typically occurs is that someone will put a sheet under a plant and beat the leaves to see how many fall out,” Tomasino says. Another approach involves walking through the vineyard and counting as many bugs as possible in three-minute increments, she says.

Troubled waters

Science journalist Dan Egan’s book, The Death and Life of the Great Lakes, chronicles the impacts of global trade, urbanization and climate change on the lakes and communities that depend on them. Invasive species, including zebra and quagga mussels, have been particularly damaging, Cassie Martin wrote in her review “Invaders, climate change threaten Great Lakes” (SN: 3/18/17, p. 30).

A translucent crab discovered nearly 20 years ago has finally been identified as a distinct species. Researchers dubbed…