Hair Raising

Here’s a flashback article in honor of the season!

Forgotten Physiology

images electric razors just don’t give you that clean shave

That’s right brothers and sisters Halloween is one of my favorite Hallmark holidays. The candy, ghost stories, bad zombie makeup, and shapely women in revealing witch costumes all put me in the holiday spirit. I have to admit though, something has been bugging me. There I was, watching cheesy, poorly scripted thriller movies at 1am alone in my creepy old apartment. I’m watching one of those scenes where the woman in a low cut top is searching the basement with a flashlight for strange sounds when I feel the hairs raise on the back of my neck. “Why is that?” I think to myself. No, I know why MY hairs stood up. I’m a total wuss when it comes to ghost thrillers, but why does that physiological response happen to all of us when we get spooked?

scared cat cat demonstrating pilomotor response…

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Loud and Clear – the science of sound

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I’ll bet her hand tells the best jokes

 

You may not know this but…

we are in possession of ancient technology. I’m talking about Men in Black, Star trek phaser-level technology. Forget about your smartphone or the connectivity of your Wi-Fi to your oh so shiny tablet (yeah..your tablet is boring). We have ears! Do you understand how remarkable the phenomenon of hearing is?! Mammalian ears are a curiously sophisticated adaptation. They’ve crossed species borders and traveled the millennia just to stay virtually the same. As far as mammals are concerned, version 1.0 is still the best thing out there and those cute little ears of our furry ancestors have been around since the dinosaurs. Archaeologists in China discovered the fossil of a 195 million year old mouse-like mammal (Hadrocodium) with a fully developed inner ear, not unlike what we have today. That’s the physiological equivalent of finding King Tut’s blue-ray collection.

philos

Do we hear with our ears or with our brains?

Sound Waves and Philosophy

Sound is a physical property. Sound happens because people and animals and objects interact with the physical environment and the resulting energy of those interactions is transferred into sound waves that travel through air, water, asphalt or whatever. What we “hear,” on the other hand, is what our brains say we hear. Our brain translates that physical phenomenon into an experience and our brain instantly labels that experience as familiar or unfamiliar, safe or dangerous, pleasing or Nickelback.

Ear Anatomy

The pinna, that floppy, fleshy, flap of skin and cartilage on the outside of our heads is a total cover girl. It’s the most recognizable part of the ear and it helps to funnel a small portion of the infinite variety of sound waves whizzing pass our heads every second of the day. However, to learn the secret to the riddle of sound we need to look beyond the pinna, down the icky, wax filled canal (external auditory meatus) into the middle and inner ear where the tiny bones and membranes play percussion for our central nervous system.

ear-anatomy

The path of sound…

Tempanic > malleus > incus > stapes > oval window > vestibules > cochlea > Brain!

Once sound waves slinky down our ear canal they reach the tempanic membrane (ear drum) and that’s where the magic really happens. Waiting just behind the tympanic membrane is a highly specialized set of tiny bones (ossicles) that move in sync with each vibration.

At this point we have this nifty domino effect happening where vibrations move from one tiny bone to the next. That’s right, I said “vibrations.” Sound is energy and it behaves the way all energy does, never destroyed just moving from one form to another.

Anyway, vibrations move from the tympanic and then pass the baton to the malleus, along to the incus, and then to the tiniest bone of all, the stapes.

Here’s where it changes up a little. Those 3 bones I mentioned occupy this air filled space (tympanic cavity), kind of like a hallway in your head and at the end of that hallway is a door (or rather a window), the oval window. This window is a part of the next compartment of the ear. When that vibration reaches the stapes it basically knocks on that window, handing off the remaining sound energy to the inner ear.

Keep in mind that this is all happening at the speed of sound. Sound waves gallop along at a healthy pace of 1,126ft/sec through the air. Just imagine jumping 13 train cars in a fraction of a sec. Of course, your ear canal is only about an inch long so this all happens MIGHTY quick.

The inner ear is like another dimension. There are fluid filled vessels and a chamber at the end shaped like a snail shell with hairy receptor cells transmitting signals to the brain. I mean What?! It sounds like the hallucination of a band groupie at a Pink Floyd concert, but it’s real.

So what happens?

The stapes knocks on the oval window, transferring the sound vibration to fluid contained behind the window that will move along tubular ventricles.

So in case you got lost, sound moved down the pinna, through the canal, to the tympanic, shaking hands with the malleus, incus, and stapes hanging out in the hallway of the tympanic cavity where the stapes bangs on the oval window to stir up some nasty fluid on the other side.

This fluid (endolymph) now surging with sound energy, will transmit vibrations within the coiled vestibules where they connect with a spiraled chamber called the cochlea.

OK…here it is..

Tucked inside the cochlea is a layer of epithelial receptor cells that make up the Organ of Corti. As the energy charged fluid passes over the tiny hairs of these cells an electrochemical signal (neural transmitter) is released. Neural transmitters are basically like biochemical text messages, but instead of going through Verizon or Sprint this message travels down a bundle of nerves called the spiral ganglion where the temporal lobe of your brain is waiting to…well..”hear” it.

Stay curious, stay classy, and never stop learning my friends 🙂

Down for the Count – Calories

4281216-0866640711-muham“Really, calories again?” Yes, I can just feel your eyes rolling from across the internet, but don’t worry, I’m not here to point out every
bad decision you’re making with your diet. Trust me, I’m eating a blueberry doughnut right now and it’s not for the vitamin C. Today
I want to go “behind the music” of one of the most notoriously misunderstood bad boys in nutrition today, the calorie.

True story…

Manufacturers will use terms like “50% less calories” and “50% less fat” interchangeably on the labels of everything from candy bars to ground pork to persuade consumers, because they know a simple, ugly truth; many of us don’t know the difference.

The Lie… 

calories = fat (NO!)

The Simple Truth…

Fats contain calories (YES!) and so do proteins, carbs, and alcohol

– so if Katie and Sara both order tall chai lattes but Katie orders the reduced fat latte (because you know how Katie is) then Katie’s drink will have fewer calories than Sara’s, because there are fewer fat based calories present (and because Sara lives on the edge).

Simply put, a calorie is a unit of measurement for energy, heat energy. In chemistry it’s the amount of energy needed to raise the temperature of 1 gram of water by 1 degree. We call this a “small” or gram calorie. It is, as French scientist Nicolas Clement
described it, a unit of heat.

The calorie we commonly associate with nutrition is a large or kilo calorie. One kcal provides the energy required to raise 1kg or 1000
grams of water by 1 degree.

WHOAH!…………Chord change……..SLOW IT DOOOWWwwnn..

frap - Copy

I’m just saying…

frap3 - Copy

What does that have to do with food?

When we talk about the calories in foods we are describing how much potential energy per volume (grams/fluid ounces) is locked
inside that grilled chicken Caesar wrap or the salted-caramel frappuccino you’ve convinced yourself is not a milkshake. That energy is
released once we ingest the wrap and our digestive hardware gets busy metabolizing the fats, proteins, and carbs.

Fats, despite what you think about them or their political views, have more than 2 times the energy of carbohydrates or protein. The
chemical bonds holding fat molecules together just have more juice in the battery.

See what I mean:

Fat: 1 gram = 9 calories
Protein: 1 gram = 4 calories
Carbohydrates: 1 gram = 4 calories

and so what’s the problem with fat?

First let me say everybody needs to ease off on the recent, anti-fat campaign. We need fats to operate. The lipids and triglycerydes in fats line our cell membranes, make up the bulk of our hormones, and even insulate our neurons.
The problem with fat is storage. Fat just tends to hold on to more calories than we can use at one time, and what we don’t use gets stored right out in the open for everyone to see (I’m looking at you love handles).

We do burn fat for energy at some point. Carbohydrates are just more readily available since they are essentially just long chains of sugar molecules. Metabolically speaking, sugar is as easy as paying with a debit card as far as your cells are concerned (fat is like an old, wrinkled check folded up in your wallet). When the carbs get used up we begin to breakdown fat in a process called ketosis whereby enzymes acting
on fat cells persuade them like cellular loan sharks to give up their precious triglycerides (composed of a glycerol and three fatty acid chains) which then venture out into the bloodstream to make themselves available for cellular respiration and ultimately ATP synthesis.

Believe it or not, even fat burns calories, just not as efficiently as muscle cells. Your resting metabolism (A.K.A basal metabolism) is burning calories just to operate. The body is a machine whether you like that analogy or not and it burns fuel just to keep the engine running. We even burn calories when we digest food. Fats not only have more calories, it takes fewer calories to digest them. They’re
like a roommate that only has to pay a fraction of the rent but has 3 times more stuff than you just cluttering up the living room.

Muscle on the other hand is a calorie burning mad man. It is metabolically expensive for the body to maintain muscle tissue because muscle fibers work hard and demand compensation (talking about calories…see what I did there?). So if you truly want to burn calories you need to improve the ratio of fat to muscle in your body.

90s

that’s so 90’s

The way I see it (A.K.A the right way, most awesome way, best way, etc.) we need to change our philosophy about exercise. Sure, we want to burn calories, but that would involve burning more calories than you consume and that’s about as effective as hiking up a ski slope with roller blades on…which is pointless and just way too 90’s.

Perhaps we should exercise with a mind-set to condition and build muscle. That way your metabolism can start working for you and not against you. Of course, it also helps to limit the amount of fat based calories your body would need to burn in the first place. Sorry, nothing is ever easy. I don’t care if you call it a diet or not. There’s just no such thing as a reduced fat “Baconator.” If you cut out fast food then you’ve done half the work already. Hey look at me,…I care.

Stay curious, stay classy, and never stop learning my friends 🙂

Secret Life of Yawns

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9 out of 10 Beagles prefer French roast

I have to be honest with you my friends, after many hours of extensive research (2 whole hours) I just can’t wrap my head around this topic. I’ve flipped through page after page of neurophysiology, human anatomy & physiology, and re-runs of Bill Nye the Science Guy. All the while this topic mocks me from across the room, laughing and pointing at me while I stand vulnerable with my intellectual fly open. Yes my friends, the question of why we yawn is quite the physiological puzzler. So allow me to share what I’ve learned so far.

PANDICULATION! (get your minds out of the gutter…I was here first)

Pandiculation refers to the act of yawning and stretching at the same time. It’s that moment we’ve all witnessed when a dog first wakes from his nap. They’ll stretch out onto their paws in that awkward straddle that always reminds me of yoga on stilts. They then open their jaws impossibly wide and yawn. We may not be as cute as our fury friends when we do this but all the tell tale signs are there. Also, have you ever noticed how unsatisfying a yawn without stretching is? In fact, it is suggested that this is one of the main advantages of this activity. What other involuntary responses to stress, fatigue, and boredom do you know of that simultaneously stretch your jaw, tongue, throat, and eardrums aside from dry heaving?

So what does yawning do for us?

Here’s where the theories rear their ugly, wishy-washy heads. As you know, it has always been my mission to give you the facts – raw, unfiltered, with no artificial fillers or sweeteners, but surprisingly, there are more theories on this subject than Rihanna has hairstyles. So here are my top 3 favorite explanations:

Theory #1 – Increased CO2

This charming little theory has been circulating like an urban legend for eons. It suggests that yawning is triggered by a shift in the concentration of CO2 in the blood. Remember that breathing is a kind of constant exchange of oxygen for CO2 and it is just as vital to rid the body of the CO2 generated during the daily metabolism of our cells as it is to take in oxygen. So the idea that the sudden and deep inhalation of air taken in during a yawn is the body’s way of self-regulating for these shifts makes perfect sense to me.

Upon experimental investigation with test subjects however, increasing oxygen and reducing CO2 seemed to have no measurable effect on the incidences of yawning. Sorry CO2, you can take away our polar caps but not our right to yawn.

Theory #2 – Brain Temperature

This theory suggests that yawning is a means of cooling off the brain. As a fan of Sci-fi I dig this explanation because I like to imagine the brain overheating like a high-tech super computer developed in a secret government lab. So in order to keep our test tube, android bodies from nuclear meltdown we have to yawn occasionally.

So it’s not more oxygen that our yawns are bringing in but cooler air to lower our body temperature. When you think about it, the hypothalamus of the brain regulates body temperature anyway. Yawning could just be a sign that our internal thermostat is kicking in. Since body temperature fluctuates with our sleep cycles, it is believed that cooling off the brain heightens alertness and mental efficiency. In fact Alertness ties in beautifully with our third and final explanation….

Theory #3 – Alertness

This is my favorite (my blog defies science and thus picks favorites). This theory argues that yawning is an activity evolved to promote not only alertness but a kind of group vigilance.

fun fact – I yawned approximately 17 times in the process of editing this article.

From the moment we wake our inner clock is ticking, counting down the hours until sleep. As the light changes throughout the day, adenosine (neuron inhibiting, smooth talker that gets your central nervous system into bed) accumulates in our cells like sand at the bottom of an hour glass. Your awareness to stimuli, reaction time, and perception of subtle changes in the environment becomes muffled and muddy. Staying vigilant is crucial in a prehistoric wilderness of dire wolves and sabertoothes that think of homo sapiens as walking, P.F. Chang appetizers (I like the spring rolls).

earlymanSo there you are, standing guard by the cave with your hairy arms and caveman abs. Having just chowed down on grilled mastodon your eyes start to droop. Your respiration shallows and your body temperature fluctuates, but just then, you hear bushes rattle in the distance. The sudden sound makes your shoulders jump (known as a hypnic jerk), jolting you back into consciousness. You smell the distinct musk of a predator dangerously close by. Reaching for your flint tipped spear you start to…yawn? The other members of your tribe also reach for their weapons. Women gather up the little ones and they too begin to yawn (a phenomenon of contagious yawning observed primarily among relatives and close friends rather than strangers). The yawning stretches the jaw, tongue, eardrums, and throat. Arterial blood flow is increased, allowing the brain to cool, prompting arousal just in time to perceive the threat of wolves approaching…or so the theory goes.

Stay curious, stay classy, and never stop learning my friends 🙂

 

 

 

That Carpal Tunnel Thing…

Body parts are like politicians. You don’t really think about what they do until something goes wrong. Consider the median nerve. “What’s that?” Well it’s only the peripheral nerve responsible for sensation and motor control of the fingers within the palms of each hand (except for the little finger, but pinkies have problems with authority).

"You say it your way and I shall say it mine."

“You say it your way and I shall say it mine.”

Don’t feel bad if you’re not facebook friends with the median nerve. It never really hits the news until it gets squeezed. Yes, squeezed. Everyone has heard of Carpal Tunnel syndrome, Carpal Tunnel, or “Copper tunnah” if you were raised in the land of sweet tea and magnolias.

The carpal tunnel is a narrow channel of ligaments and bone in the wrist that the median nerve passes through like the DC metro train. In carpal tunnel syndrome this space begins to narrow, compressing the median nerve which leads to numbness and chronic pain in the hand, fingers, and wrist.

What causes the squeeze?

_CARPTUN

I really wanted to give this diagram a high five just now. Weird, I know.

Did I mention that the carpal tunnel is narrow? No space is wasted in the body and the median nerve isn’t just floating happily in first class with all the leg room in the world. It is literally surrounded on all sides by 9 flexor tendons, vessels, small muscles, and of course, the carpal bones of the hand. In such a tight space if any one of those tendons decides to swell (and you know how tendons can get) the median nerve will get squeezed tighter than a dachshund wrestling a Saint Bernard for a bean bag chair.

I’ll just give you a moment to absorb that imagery…

Risk Factors

“Risk” is just a sly statistical term to describe how much wiggle room an individual has in avoiding a disease or condition. In this case, risk factors include any condition that could significantly alter the space within the carpal tunnel.

Injury – wrist fractures, and dislocation of the carpal bones of the wrist

Chronic Illness – Diabetics or anyone with an increased risk of nerve damage, Impaired kidney function, obesity, prolonged fluid retention during pregnancy, or persistent inflammatory conditions

and then there are the Statistically cursed…

fibro-wrist-pain-400x400

“Why did I play World of Warcraft for 7 hours Yesterday?”

Statistically women are 3 times more likely than men to develop CTS, possibly due to their smaller carpal tunnels. Of course, those women who do develop CTS could have any combination of the risk factors that I mentioned above. So I wouldn’t go out making predictions at the bar with your tape measure just yet. A perfectly healthy woman or man with no signs of CTS could have smaller wrists than a woman with CTS.

Work Related? – There are a lot of people (including myself) who associate CTS with mind-numbingly repetitive tasks, such as typing or assembly line work. We can’t start pointing the finger at any one profession (and I know you want to). We can’t just say, for example, that packaging chicken parts for Tyson causes carpal tunnel syndrome. However, it has been established that CTS is three times more common among assembly line workers than individuals who perform data entry.

Any prolonged activity that puts stress on the wrist could easily exacerbate an underlying condition that could lead to CTS. Even if you have wrists the size of tree trunks I wouldn’t compete in any 3 day, speed origami marathons until all the facts are in.

Stay classy, stay curious, and never stop learning my friends 🙂

 

 

Mosquito Profiling?

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Observe, the enemy!

So I feel a little awkward asking you this but…do you often have this feeling you just can’t shake that someone, somewhere is out to get you? Does it seem like trouble follows you wherever you go? I know your friends and family think you’re paranoid (I’ve heard them talking) but listen, I believe you. There is an ancient evil lurking in the shadows that is out to get all of us and it is a fraction of a centimeter in size. That’s right, I am talking about mosquitoes, the phantom buzz in your ear that wakes you on summer nights, those bite-sized bio-terrorists that have spread disease over the millennia. I know what you’re saying, “what does this have to do with physiology? Have you been drinking?” No, but thank you for asking. The truth is some of us DO get singled out by these tiny demons more than others. What is it about us that draws them to us like…little old ladies to a yard sale…no wait, like a wrestling team to half-priced burger night? Let’s talk some physiology!

Know the Enemy

Once upon a time called 170 million years ago a family of tiny flies (Culicidae) made a bold, annoying, adaptive leap in their evolution. It discovered an inexhaustible, readily accessible food source, human blood, and they’ve been tailgating our cookouts for as long as we’ve been drawing doodles on cave walls. That’s right, they are flies, meaning that they have an additional set of modified wings along their metathorax (oh, you care). Of course, there are more species of mosquito than YouTube Harlem shake videos but one characteristic they all seem to share is that the females are the blood drinkers. They have hungry mouths to feed after all, hundreds of tiny eggs that they can lay on the surface of still, stagnant water. Their versatility is our problem. Mosquito larva are aquatic and don’t require large ponds to spawn. In fact, their breeding sites can range from ponds to plastic kiddie pools, to a neglected paint bucket left out in the rain. The point is mosquitos are opportunists who will go after the easiest meal they can get and let’s face it..we’re pretty easy.

But why me?!

Oh if you want theories I’ve got theories, but how about we stick to statistics for now. They seem to prefer pregnant women, obese individuals, and adults over children. Mosquitoes are tiny beings flying around in an enormous space. They use their sense of smell, sensitivity to movement, and Jedi mind powers (aka unknown factors) to detect our body heat, movement, and CO2 production. Adults produce more CO2 and conserve more heat than children. Of course, some people naturally have higher body temperatures and children are constantly in motion so it really depends on who is hiking with you. Pregnant women also produce more CO2, their body heat spikes, and they have an increase in the amount of circulating blood. Mosquitoes also love us after a good workout. They have a demonic sense of smell and many compounds such as lactic acid are excreted in our sweat that draw them in like a terriyaki
marinade. Our body heat also spikes when we workout but I didn’t have to tell you that.

Picky Eaters?

They also seem to have a preference for blood type. People like myself with type O blood are far more likely to get bitten (mama told me I was special). If you’ll recall, type O blood cells lack the surface antigens A or B. The absence of those antigens or “O” is how it get’s it’s name. Why don’t you meditate on that for a while.
Studies have also shown that blood cholesterol levels are a factor which is just another reason to skip that drive-thru on the way home and stick to your New Year’s resolutions…that’s right, we all heard you.

Stay curious, stay classy, and never stop learning my friends 🙂

 

Me Talk Pretty – Cross extensor reflex

That’s right party people we’re not done. You get two zesty physiology terms relating to the body’s response to pain for the price of one. Now that’s a value! Ok maybe I was just too lazy to include this one in our last brief chat about pain. I’m only human. Don’t make it awkward (I can feel you judging me and it’s so cold).

Well in addition to our lighting quick withdrawal from pain (NFR) orchestrated by sensory neurons, interneuron connections, and the spinal column, our body takes counter measures to maintain balance and stability. That’s right while one foot dodges sharp objects the other foot plants firmly on the ground to keep balance. Like the withdrawal reflex, this occurs within a fraction of a second as well. It is an opposing process. While flexor muscles on one side contract (for example hamstring muscles on the side of injury) the extensor muscles on the opposite side relax (quadriceps of the supporting leg relaxes to fully extend and support the weight). Once the pain receptors on the effected side are triggered by a pain stimulus (broken glass, sharp nail, etc) that signal flows down the sensory neuron like telephone wire to the spinal chord. From there the signal crosses over to the opposite side of the spinal chord to an excitatory interneuron. An alpha neuron takes it from there to its final destination, the neuromuscular junction controlling the extensor muscles in the opposite leg. This allows the weight to be evenly distributed to the support leg thereby taking pressure off of the injured side, minimizing further injury. I love a happy ending.

Stay curious, stay classy, and never stop learning my friends :-)