Friday, 26 June 2015

Sketchy Fact #95: Cruisin' for a Bruisin'

The changing colours of bruises is a result of your body breaking down and reusing the hemoglobin in spilled blood cells. Hemoglobin is broken down into a green pigment called biliverdin. Biliverdin is broken down into bilirubin, which is a golden brown colour.

Wednesday, 24 June 2015

Sloppy Science: Why does alcohol get you drunk?

Few substances have as long and strange a history with the human race as the collection of liquids we call alcohol. For about as long as humans have been living together in large groups we have been consuming, fighting over, and occasionally procreating as a result of what is basically a low-grade poison.

The alcohol that we know and love (found in beer, wine, hard liquor, etc.) is called ethanol and it may disturb you to know that it is actually the waste produced by unicellular fungi called yeast. Yeast loves to eat/react with sugar, and when that happens ethanol and carbon dioxide are expelled. Humans make use of both of these products. When you bake a loaf of bread it is the carbon dioxide bubbles that make it rise as the alcohol is evaporated away. In beer, the same carbon dioxide produces fizzing as the alcohol primes you for karaoke.

The amazingly simple chemistry and minimal ingredients involved are the reason why many researchers believe humans were drinking wine 3,000 years before we invented pottery or the wheel. Yeast thrives on the skin of fruit and when that fruit starts to decay the yeast gains access to the sweet sugars within. Half-rotten fruit (especially grapes) is basically booze waiting to happen. It wouldn’t have taken much for Neolithic people to put two and two together and start serving fermented grape juice (AKA wine) with their mammoth steaks at dinner parties.

But why do we love alcohol so much? To answer that question you need to understand what happens when ethanol gets into your body: When you drink alcohol it makes its way through your stomach into your small intestine, where nutrients are absorbed by the blood. Ethanol isn’t much of a nutrient but it can still hitch a ride on your blood cells to any tissue in your body that contains water (they all contain water). Your brain in particular is a veritable paradise for the stuff. Alcohol is processed by the liver and kidneys and broken down/removed from the body at a rate of about an ounce per hour, it is also a diuretic, meaning it makes you pee a lot, but when you drink more than your body can process ethanol starts to build up in your tissues. That’s where the fun begins.

In your brain, ethanol slows things down. That is why we call it a depressant. Your brain contains different neurotransmitters, some activate parts of your brain (excitatory neurotransmitters) and others de-activate parts of your brain (inhibitory neurotransmitters). Alcohol stimulates the release of GABA (gamma aminobutyric acid) which is inhibitory and it prevents the release of glutamate which is excitatory. The influx of GABA turns down the parts of your brain that control inhibition, making you say and do things you would otherwise consider a bad idea. At the same time the parts of your brain that control reaction times, balance and coordination also get dialed down, making you clumsy and a bad driver. Too much alcohol can even turn off the parts of your brain that remind you to breath or gag, an effect that has robbed the world of many a great musician. We call this “alcohol poisoning.”

But beyond all of this flipping of dimmer switches, alcohol results in a flood of the neurotransmitter dopamine in your brain’s reward centres. The same thing happens when you win a hand of blackjack or steal a kiss from someone you like. It is addictive. That is what makes alcohol dangerous.

In the short-term, processing alcohol is a drain on your body’s water resources. As your body tries to flush your system through constant peeing and your liver uses even more water to break down ethanol, other parts of your body get dried up, including your brain. That is why you often feel so rough the next day. You brain has literally shriveled up and the tissues throughout your body cannot work how they are supposed to. Other important chemical balances like the level of potassium in your blood also get out of whack. Over the long-term, your liver is damaged by repeated exposure to the waste products released as ethanol is broken down. Your liver is a pretty important organ if you like being alive.

There is some evidence that a single beer or glass of wine per day may have long-term health benefits for some people, but that just speaks to what the role of alcohol should be in anyone’s life. As with most things that you end up craving, the name of the game is moderation. 

Friday, 5 June 2015

Sketchy Fact #94: Kurt Vonnegut vs. The World of Science

Scientists recognize 16 different types of ice that form under different atmospheric pressures and temperatures. The stuff in your freezer is Ice IV.

Wednesday, 3 June 2015

Allergies: Why Your Body Hates You

Billions of years of evolution have crafted your body into a high octane, fuel burning, disease fighting machine. There are so many processes going on in each of the quadrillion-odd cells that you are made of that scientists are only beginning to scratch the surface of basic things like nutrition and diet. However, just because your body is impressive doesn't mean that it is perfect. Occasionally, for some of us, the actions our bodies take to keep us alive can lead to intense discomfort or even death. The best example of this type of mishap is allergies.

In the world of medicine allergies are referred to as an autoimmune disease, meaning that the immune system that is meant to fight of invading parasites and viruses mistakenly attacks a person’s own body. They occur in roughly 10% of people (slightly more in developed countries, but we’ll get to that) and lead to a cascade of bad times for sufferers.

Becoming Allergic

The way allergies work involves a couple of crucial steps that are better explained in fun, cartooning sketches than paragraphs of text:

First, some new material enters the body where immune cells (the police force of the body) suspect it is up to something fishy. This is known as the "sensitizing exposure" and means that the first time an allergic person comes into contact with the thing they are allergic to, nothing happens.

The immune cells report back to the lymph nodes (their police HQ) and tell the body to produce antibodies (AKA immunoglobulins) to fight off the invading material, also known as the antigen, in the future. (Thank you to the readers who caught our mistake, switching antibodies and antigens)

The antibodies (specifically one called immunoglobulin E – IgE for short) attach to “mast cells” throughout the body where they begin a stake-out for the suspicious material.

The next time the new material shows up in the body, it is attacked mercilessly by antibody-clad mast cells. This is the equivalent of activating the army, navy, special ops and coast guard against girl guides trying to cell cookies.

When mast cells attack their targets, the effects on the body can be pretty terrible. Chief among them are the dilation (expansion) of blood vessels and the flooding of the area between cells with fluid. Dilated blood vessels lowers blood pressure and can starve organs of the oxygen they need to function. Fluid between cells causes swelling which can make you look like a puffy, lumpy version of yourself in addition to closing your throat so you can’t breath. The areas of the body with the most mast cells (skin, nose, throat, intestines, etc.) tend to be hit the hardest.

The Hygiene Hypothesis

So if allergies are so clearly bad for us, why hasn’t evolution naturally selected against them? The question is actually a surprisingly hard one to answer. The truth is, no one knows; but there are two main schools of thought.

First is the idea that allergies are a reaction that benefited our bodies in the recent past. Specifically, a lot of researchers think that allergies are meant to protect us against parasitic invasions. However, since parasites are a less common component of our diets than they used to be our bodies end up overreacting and freaking out when we breath in pollen instead.

Alternatively, there is the idea that putting ourselves in a protective, germ-free bubble for the early part of our lives has compromised some children’s abilities to develop fully-functioning immune systems – the so-called Hygiene Hypothesis. Basically the body isn’t exposed to as wide a range of microbes as in was in generations past, but it still expects to be. The long wait between attacks makes your immune system paranoid it starts labeling harmless things like peanuts, pollen and shellfish as terrorists. This could explain why allergies are more common in developed countries and are on the rise in rapidly developing nations.

If you suffer from allergies, the best treatment is avoidance. If your allergies are severe and sneaky you might need to carry an epi-pen, which is a shot of epinephrine that constricts your blood vessels and opens your airways. Epinephrine is produced naturally in the adrenal glands and is usually not called into action unless you need to run away from a lion or something. Alternatively, if you love the thing you are allergic to (ex. your dog), you can try immunotherapy which attempts to build up a tolerance through increasingly potent injections of the protein you are allergic to. If you have a food allergy, sometimes cooking the food can destroy the protein that causes the reaction (as is the case for our illustrator with carrots), but this is not something worth experimenting with if you are hyper-sensitive.

The important thing to remember is that we are still learning about allergies. New research is leading to new discoveries, but we still don’t know everything. With that in mind, take things like the hygiene hypothesis with a grain of salt. In short, we don’t know enough for you to leave your baby in a tepid pool of pond scum… yet.