Washington State University

Ask Dr. Universe

Whistle while you sleep!

January 3rd, 2013

When I’m tired, where exactly am I tired?

Rafael
Madrid, Spain

Two ironing women, by Edgar Degas. Musée d'Orsay

Two ironing women, by Edgar Degas. Musée d'Orsay

Well, it depends. What kind of “tired” are you talking about? If you’ve been exercising, the answer’s pretty clear, says James Krueger, a sleep researcher here at WSU. The tiredness is in your muscles. What’s not so clear, though, is how that tiredness relates to sleep.

This is an excellent example of the trouble that being scientific gets you into. If you don’t worry about the details, no big deal. You work hard. You get tired. You go to sleep. You wake up ready to go again.

But of course, the body isn’t quite that simple. Like everything else, the body is full of causes and effects. Connecting those causes and effects is the hard part. If you exercise heavily, says Professor Krueger, the number of white blood cells in your blood goes way up. White blood cells are the front line of your immune system. Also, your body produces all sorts of cytokines. These proteins regulate your immune system.

What’s interesting is that some of these cytokines are also involved in regulating sleep. And they’re also what give you that achy feeling when you’ve exercised a lot. Interestingly, even if you don’t exercise, but don’t get any sleep, your muscles will ache.

Now, if our science were perfect, at this point we’d put the pieces together and say AHA, this is what “tired” is all about. But all we can actually say is that some chemical signal is generated in your muscles, that signal is sent to your brain, and your brain interprets it as “tired.”

Speaking of your brain, that’s another story. Even though you feel tired when you don’t get enough sleep, your brain itself doesn’t really feel “tired.” In fact, according to some recent experiments, it seems that when you’re asleep, your brain is actually going over things from when you were awake. Some birds, for example, seem to rehearse their songs while they’re asleep!

So if your brain isn’t tired, why does it have to sleep? And how much of the brain goes to sleep when you’re asleep?

It doesn’t seem like single cells go to sleep, says Professor Krueger. On the other hand, we know that the whole brain doesn’t need to go to sleep for you to be “asleep.” Some animals, for example, go to sleep half a brain at a time. Some researchers recently found that when a flock of ducks goes to sleep, the ducks on the outer edge will sleep with one eye open and half their brain awake while the other eye and brain-half are asleep! Whales and dolphins also sleep a half-brain at a time. That’s how they keep from drowning while they sleep.

But back to “tired.” What IS that tired, groggy feeling you feel when you haven’t had enough sleep? “We really don’t know,” says Professor Krueger. You lose the ability to focus and concentrate. You don’t think clearly. You get uncoordinated. But what exactly does it mean? That’s part of what sleep researchers are trying to figure out. That – and why exactly we need to sleep.

Most of that tired feeling you get in your muscles can be cured by just resting. So why do we need to be unconscious for eight hours every night?

Professor Krueger believes that sleep helps the brain save its “synaptic superstructure.” What this means is that your genes gave your brain a certain pattern of synapses, or connections between neurons. During the day, your brain is constantly rearranging itself and reforming patterns and talking to itself in different ways. What sleep does, thinks Professor Kmeger, is shift these synaptic patterns back to their original design!

Talk, talk, talk

January 3rd, 2013

Who invented language?

Matthew
Hubbell, Michigan

 Young chimpanzees from Jane Goodall sanctuary of Tchimpounga (Congo Brazzaville). by Delphine Bruyere, Wikimedia

Young chimpanzees from Jane Goodall sanctuary of Tchimpounga (Congo Brazzaville). by Delphine Bruyere, Wikimedia

Well, I might as well admit right up front – we don’t know. But that doesn’t mean there aren’t some great arguments about who invented language. I got an earful about all this from Nancy McKee, who is a linguist and anthropologist here at WSU. That means she studies language and people.

It’s hard to say who invented language, says Professor McKee, because words don’t leave fossils. The only absolute evidence of language is writing. But think about this: As recently as the last century, the majority of the world’s population did not write. Of course that doesn’t mean they didn’t have language.

The oldest example of writing that we’ve found is a kind of writing called cuneiform, which was used by the Sumerians, people who lived in western Asia. The oldest examples of cuneiform are about 5,000 years old. Of course, language is much older than that.

But how do you figure out who invented language if there isn’t any written record?

First, says Professor McKee, you can look at the STRUCTURE of the brain. In other words, you can look at the brains of human ancestors to figure out whether they talked or not. The only problem with this is that brains don’t leave fossils either. All that lasts are the skulls, which are often broken, so you have to piece them together. Even so, scientists can tell quite a lot not only about how big the brain of the ancestor was, but how it was organized.

Another way to study when language came about is to study humans’ closest relatives, chimpanzees and the other great apes. First of all, they can’t talk, says Professor McKee. They COMMUNICATE. Slime molds communicate, she says. But slime molds don’t TALK.

When chimpanzees see food, they go UH! HUH! EEEE! HUH! HUH! Or something like that. Of course that lets the other chimps know about the food. But the chimp doesn’t necessarily WANT the others to know. In other words, they don’t MEAN to say UH! HUH! and so on. What controls these sounds is a really old area of the brain called the “limbic area.” You know when you step on a tack and yell? That sound comes from the limbic area. It isn’t something that you SAY or mean to say.

In other words, says Professor McKee, much of what chimps say is involuntary. As Noam Chomsky, another linguist, has said, saying a chimpanzee can talk is like saying a man who jumps off the Empire State Building can fly!

Now, Professor McKee’s opinion isn’t quite so extreme. She thinks that chimps really are pretty smart. It’s just that they’re really dumb compared to humans. For example, they do not talk about the nature of evil. However, when they learn sign language and tell the human studying them that they want some food, they mean they want some food. It’s not just a “conditioned response.”

So what does this have to do with the invention of language? Chimpanzee brains are about one-third the size of modem human brains. If chimps can “say” through sign language simple things like “I want dinner,” then human ancestors with much larger brains probably could do just as well and probably better.

So what ancestors are we talking about here? Professor McKee thinks it was these folks called “Homo erectus,” who had brains twice as large as chimps and who seem to have evolved about 2 million years ago from an earlier earlier ancestor called Australopithecus. (Just sound it out and say it loudly.)

The scientists who think about language are basically divided into two camps. Some think that language just happened all at once. SOMETHING very remarkable happened somewhere along the line. Maybe it was some kind of evolutionary adaptation. For whatever reason, these scientists believe there’s a BIG BREAK between humans and other animals that communicate.

Professor McKee belongs to the second camp. She believes that language is just the endpoint of a gradual evolutionary process-beginning with slime mold-that simply became more and more elaborate.

But still, when did it become “language”?

Somewhere between 2 million and 200,000 years ago, she says. Well, that certainly narrows it down!

Still, she doesn’t think that Homo erectus perfected language. It might have taken until about 40,000 years ago before there was anything like modern language.

GARGALESIS!

January 3rd, 2013

Dear Dr. Universe,

Please, we need your help!!! We want to know what makes people ticklish? Why do we laugh when we are tickled? And why are we sometimes ticklish and sometimes not?

Michelle, Sarah, Jacob, Micah, Jeremy, Austin and Taylor
Phoenix, Arizona

Laughter from tickling. David Shankbone, Wikimedia

Laughter from tickling. David Shankbone, Wikimedia

“Tickle” might just be a side effect of some other effect way back in our evolutionary history, says Patrick Carter, who studies the evolution of physiology here at WSU. That means he studies how and why we came to look and operate the way we do.

Professor Carter admits that thinking about tickle can be a lot of fun, and a lot of scientists and philosophers have even thought pretty seriously about it. Socrates, Plato, Francis Bacon; Galileo, and Charles Darwin all thought and wrote about tickle. Because none of them figured it out, though, we’re still working on it.

First, let’s think about types of tickles. I’m sure you’ve thought about how a little tickle, say with a feather under the chin, is different from a serious tickle, like when your buddies tickle torture you.

Scientists call the light tickle KNISMESIS and the heavy tickle GARGALESIS.

Great words, huh? Hey, how about a little gargalesis?

So anyway, where did tickle come from? Depending on who you talk to, the knismesis variety is pretty clear. It probably has to do with the feeling when a tick or other insect is crawling on your body. It tickles, and you brush it away or squash it.

That’s probably too neat an explanation, but what can I say?

Gargalesis is definitely more complicated. WHY would we start laughing hysterically when somebody digs her fingertips into our sides? It seems pretty ridiculous.

Charles Darwin thought that the tickler’s and the ticklee’s relationship had something to do with whether gargalesis was pleasurable or not. Even though a child might enjoy being tickled by a parent, being tickled by a stranger would be frightening.

To test this, psychologist Christine Harris at the University of California, San Diego, built a tickle machine. She figured that if Darwin was right, people would at LEAST need to think they were being tickled by a person, not a machine.

What she found out, however, was that it didn’t make any difference what the subjects thought they were being tickled by.

Another thing that Professor Harris has found is that tickling and humor are not related. She had a bunch of students watch a funny video and then tickled them. Others watched a not-so-funny video and then got tickled. This relied on the “warm-up effect” – if you think something’s funny, the next funny thing that happens is even funnier, and so on.

The result of the experiment? No effect. Tickling does not create a pleasurable feeling, says Professor Harris, just the outward appearance.

So where does that leave us? What IS gargalesis?

Maybe it’s just a reflex, like your leg jerking up when you tap yourself on the knee. But if so, why can’t you tickle yourself? Well, why can’t you say BOO! in the mirror and scare youself?

Actually, some scientists at the Institute ofNeurology in London decided to figure this one out. They used an MRI machine to look at a person’s brain when the person was subjected to knismesis. MRI stands for magnetic resonance imaging. It uses a very powerful magnet to look inside the body. Problem is, you have to lie very still for it to work, so studying gargalesis was out.

However, what they found was when someone else was doing the tickling, there was a lot of activity in the somatosensory cortex, the part of the brain that handles touch.

When the person tickled herself, the cerebellum lit up. So what? Well, the cerebellum handles planning. What the scientists reasoned from this is that the cerebellum knew that its person was going to tickle herself, so it WARNED the somatosensory cortex!

Okay, that’s pretty cool – but still, WHY?

Well, maybe tickling helps establish a good feeling between parent and baby – mom tickles baby, baby laughs, mother smiles and tickles some more …

Or MAYBE, says Professor Harris, gargalesis has to do with developing fighting skills. HUH? Well, your buddy tries to tickle you, and you fight her off and tickle her back and you wrestle, like kittens fighting.

You know that tickling ISN’T all that pleasant, even though you laugh. Maybe the laugh is a signal that you’re not mad. Jaak Panksepp, a scientist at Bowling Green State University, has found that rats give off a real high-pitched chirp when they’re tickled. He thinks this is like rat laughter and helps distinguish play from threat.

ON THE OTHER HAND, says Professor Carter, maybe none of this is correct.

Not everything is an obvious result of something that happened in evolution. Maybe tickle is just a side effect of something we haven’t a clue about.

In other words, we may never know for sure why we tickle. Sorry.

How many neurons does it take…?

January 6th, 2012

Dear Dr. Universe,
How does my mind work?
“SoccerGirl”
Pearland, Texas

Brain model

Brain model

Remember Gina Poe? She’s a scientist here at WSU who studies why we sleep. And why ask someone who studies sleep how your brain works? Well, the brain is what sleep is all about. But we’ll come back to that.

First, Professor Poe lists all the things your brain does:

It directs your body to move, smile, eat, run, jump, blink your eyes, laugh, and play the piano. It is where you feel joy, excitement, anger, sorrow. It tells your heart to pump and makes you breathe faster or slower according to the signals it gets from your body and itself.

The brain is where your personality lives. It is where all your memories are stored. It thinks, imagines, creates, tells jokes, understands jokes. It makes sense of your senses—your hearing, smelling, tasting, touching, seeing—which reach the brain by signals sent along your nerves.

All this, and more, it does with about 100 billion neurons, or nerve cells, which are connected to each other and talk to each other with electrical and chemical signals. Each of these neurons can connect with surrounding neurons in about 10,000 different ways! One kind of neuron, the Purkinje cell, makes as many as 100,000 connections!

Besides the neurons, there are glial (which comes from the Greek word for glue) cells, about twice as many as there are neurons. Glial cells regulate different substances (such as glucose and potassium ions) that the neurons need. They also provide a structure, or framework, for the neurons and insulate the neurons so their electrical signals work better.

Different kinds of neurons work in different ways. And different areas of the brain do different things. Even different kinds of memory are stored in different parts of your brain. Your brain, says Professor Poe, is like a small city. A brain and a city (and an ant colony—but that’s another story) have lots of different parts doing different things, but altogether they are one.

What all these different functions have in common is that the neurons make it all possible. Even though there are different kinds of neurons, they work pretty much the same way, by signaling other neurons through electrical and chemical signals and forming connections, called synapses, and forming patterns and networks with other neurons.

In fact your brain is constantly talking to itself, synapses forming, neurons forming new patterns as they react to new signals from your body and your friends and the rest of the world!

In fact, experience actually alters the “microcircuitry” of the brain. Memories, for example, can have an actual shape!

Just last fall, Swiss scientists confirmed what a lot of scientists had suspected, that neurons lock in memory not just by turning on a connection, but by actually forming new synapses.

So think about this for a little bit. What if these billions of neurons just keep doing all this, on, off, information in, information out, each neuron talking to a thousand neighbors, changing relationships from one pattern to another, then another, then another, THOUSANDS OF TIMES A DAY!

Professor Poe and James Krueger, another sleep researcher here at WSU, believe that the brain needs sleep in order to tidy itself and to strengthen some of the connections and relationships that need to last, such as important things you need to remember. The brain needs sleep to put itself in order.

And almost no one gets enough sleep. Kids, especially, need lots of sleep for a healthy brain, at least nine or ten hours. So turn off your computer, turn off your TV, and go to sleep! Your brain will work a lot better.

I want a new brain

January 6th, 2012

Dear Dr. Universe,
In our class we have studied different cells in the body. We would like to know why can’t a person grow new brain cells?
Kurk Kirby
Devin Honeycutt
La Center Middle School
La Center, Washington

Single neuron from a rat. Photomicrograph courtesy Gary Wayman.

A single neuron from a rat’s hippocampus, an area of the brain essential for learning and memory. The bulbous part is the cell body. fluorescent color markers have been attached to specific proteins to allow researchers to assess the length and complexity of dendrites (green) and the number and size of dendritic spines (red). Each spine is part of a synapse, where this neuron receives incoming signals from other neurons. Photomicrograph courtesy Gary Wayman.

I went to talk to Professor Dipak Sarkar here at Washington State University. He studies the nervous system, and he gave me a surprise. He told me that humans CAN grow some new brain cells.

But there are actually two kinds of brain cells, the neurons and the glial cells. Neurons are cells that carry information. The glial cells help support the neurons. Scientists think they also have something to do with storing your memory. So even as you read this, glial cells are continually multiplying.

As for neurons, scientists are finding that some neurons DO have the potential for division, which is how new cells come to be. For example, the olfactory neurons, which carry smell signals from your nose to the brain, are replaced throughout your whole life.

However, you are right that most neurons do not divide.

Why?

Well, it becomes kind of a philosophical question, like “Why am I?” But I know you want a better answer than that.

As you probably already know, the eventual you started out as a “zygote.” A zygote is the fertilized egg from your mom. From there, the cells start dividing and differentiating. That means they start becoming what they’re meant to be, like muscle cells and eye cells and nerve cells. Almost all of your neurons—your entire nervous system, in fact—was formed when you were inside your mom.

And here’s the really amazing part: In order to produce the eventual one trillion cells that your brain eventually has, you had to develop an average of 2.5 million neurons every minute you were a fetus inside your mom! (Just to give you an idea of how many neurons you have, let’s say you started counting right now, without any breaks or sleep or anything. Counting to one trillion would take you over 32,000 years!)

But once a neuron becomes a neuron, that’s what it is until you die. Actually, that’s not that unusual. For instance, most muscle cells do not divide. But they do grow in size. If you do a lot of exercise and get bigger muscles, you don’t get any more muscle cells. You just get bigger ones.

Same with the brain. That doesn’t mean that your brain is done growing, though! Think about it. When you were born, your brain weighed about 12 ounces. Or about 350 grams. (We’ll switch to metric, because that’s how scientists measure things.) When you were one year old, it weighed about 1,000 grams. Right now, it weighs probably about 1,300 grams. When you’re an adult, it will weigh about 1,500 grams (a little more than three pounds).

So, if you’re born with all your neurons, how come the brain gets heavier?

Well, the neurons themselves grow in size, like muscle cells. Also, you grow more glial cells, as you need more memory. (Just think how many more glial cells you’ll have once you’re done reading this.)

But once you’re about 20 years old, you start to lose neurons. In fact, you start losing about 50,000 neurons every day! By the time you’re 75, you will have lost about 10 percent of your neurons.

But this doesn’t mean that you’re only 90 percent as smart as when you were born. That’s because even though you’ve lost some neurons, the ones that are left can form new branches of fibers and new connections, or synapses, between them. These make up for the ones you’ve lost.

Finally, here’s something to think about. There are lots of things that help fine-tune those synapses and the actual development of the neurons. These things include what you eat, what you experience–and (get this) learning.

So what this means is you either use it or lose it.

Sweet dreams!

January 6th, 2012

Dear Dr. Universe,
Is there any way to enhance one’s memory?
Anders Okkelmo
Sarpsborg, Norway

Sleeping student. Marc Wathieu/Flickr

Sleeping student. Marc Wathieu/Flickr

Think about this: Think about how much you think about all day long, about how much you see, hear, smell, taste, feel. About how much you have to REMEMBER. All day long your brain is going like crazy. Your neurons (nerve cells) are constantly trading information with other neurons, joining up with them to form memories, on/off, hello/goodbye, information in/information out, and on and on, ALL DAY LONG!

Well, where does that leave your brain at the end of the day? A real mess, that’s what! And probably full of adenosine! Wait, what?

The “currency” of energy in your cells, including your neurons, is molecules called ATP, or adenosine triphosphate. As the brain cells use that energy, the ATP breaks down, leaving all this adenosine floating around in your brain. Some scientists think that adenosine triggers sleepiness.

Well, let’s suppose it does. What could this tell us about improving our memories?

I went to talk to Gina Poe, who also helped us understand stereotypes and memory. Professor Poe is an electrophysiologist, which means she measures the activity of neurons. Neurons make up most of your brain. Neurons work by communicating with each other through electrical and chemical signals that move from one neuron to the next along their synapses (SIN-ap-sees).

Professor Poe is very interested in the effect of REM sleep on memory.

REM stands for “rapid eye movement,” which describes what you do about an hour and a half after you go to sleep. During this phase of sleep, your eyes are darting around like crazy, reflecting what’s going on in your brain. Even though you are deep in sleep—and your body is actually paralyzed—your brain is just as active during REM sleep as it is while you’re awake.

Specifically, Professor Poe wonders “Is REM sleep for remembering or forgetting?” Forgetting? Well, think about it. What if you didn’t forget? Have you ever thought, “Whoa, my brain is full”? According to Professor Poe, your neurons CAN fill up. But no, you can’t use this as an excuse in class. (Your teacher is probably reading this, too, and SHE’LL know that all you need to do is get a good night’s sleep!)

So WHAT in the world is going on in there?

You’re dreaming.

But why? Why do we dream?

Professor Poe thinks that REM sleep is when your brain cleans house, when it puts things in order. Not only does it strengthen important memories, it cuts out unnecessary ones.

So how does she know this?

She studies rats and what happens to them during REM sleep. She has them run around this raised rectangular track, which has six food cups around it. Only three of them have food in them, though, so it takes the rats a while to remember which ones do.

After they have it all down, Professor Poe tests how well they remember when they don’t get enough sleep. Of course, it’s not very well. But she wants to know why. What’s the connection between memory and REM sleep?

She studies this by using probes and computers to measure how the rats’ neurons act during REM sleep.

What she’s learned so far is that neurons FIRE at different times, depending on whether they want to strengthen a memory or forget it! So again, REM sleep cleans up your memory.

So how do you enhance your memory? Tidy up your brain and GET ENOUGH SLEEP. Sweet dreams!

Yes, you are what you eat. Kind of.

January 6th, 2012

Dear Dr. Universe,
Why do people like different foods?
Nicole Ruslim
Melbourne, Australia

Fudge from Seattle's Fat Cat Fudge. by Matt Hagen

Fudge from Seattle's Fat Cat Fudge. by Matt Hagen

This is one of those very complicated questions that require a lot of experimentation. So let’s do some research on whether you and I like the same foods or not!

Seriously, lots of scientists are also interested in this question. Bob and Sue Ritter here at Washington State University have studied forms of this question for much of their careers. Sue Ritter studies appetite, or what makes us start eating. Bob Ritter studies satiation, or what makes us stop eating.

When I went to visit with the Professors Ritter, I just happened to have a bag of pretzels with me. Professor (Sue) Ritter admitted that they looked pretty good to her. It was late afternoon, and she hadn’t eaten since breakfast. Her blood glucose—a sugar that the body uses to store energy and then release it when needed—was getting pretty low. Pretzels are high in carbohydrates, which change to glucose during digestion.

Professor Ritter was also hungry for salt, which our bodies need. The sodium and chloride in salt, along with potassium, are ELECTROLYTES. Electrolytes help the kidneys manage the body’s fluid levels. Salt is also necessary for the “action potentials” that make your brain and nervous system work.

In general, when you get hungry, your body is signaling you that you need some energy. Your body has different “receptors” in the brain and other organs that tell you, I’M HUNGRY whenever they need energy. These receptors also look for specific nutrients. When they figure you’ve had enough, they send signals to the brain to shut off the energy alert.

The brain in particular says “AND I NEED IT RIGHT NOW!” Think about it. Your brain is running your whole show, which takes a LOT of energy. Even when the rest of the body is satisfied, the brain might need more energy. In fact, says Professor (Sue) Ritter, we may overeat sometimes because our brains still need energy.

And how exactly does the brain get this energy? From glucose. Glucose is the only energy source that can pass through your blood-brain barrier, which is a filter that keeps toxins away from your brain.

This does not mean, however, that every time your brain feels a little tired, you should wolf down three candy bars. There are plenty of better ways to get glucose. Fruit is a good one. Also, the brain can store only a little bit of reserve energy. If your brain doesn’t need the extra energy at the moment, and neither does the rest of your body, where’s that extra “energy” going to go? FAT!

So, to some extent, your taste for different foods is your body’s way of telling you what it needs. Maybe on Tuesday, your body feels a little low on Vitamin A. So you eat something with a taste that your body knows has provided Vitamin A in the past—carrots, maybe. Or you need some protein. So you munch a bag of nuts. That’s okay.

But just because you want salty, fatty chips doesn’t mean your body NEEDS fat. In other words, just because you’re hungry for fat doesn’t always mean you need it.

In fact, Professor (Bob) Ritter and his colleague Mihai Covasa believe that a lot of us have become IMMUNE or insensitive to fat. Their experiments suggest that if all you eat is chips and fast food, which tend to be very high in fat, eventually your body’s “I’m full” signals quit working properly.

And eventually you become what you eat. You become … fat.

I also visited Mary Watrous in the history department here at WSU. She studies the role of food in different cultures and how women carry on food traditions. She says that people like specific foods because that’s what everyone else in their culture eats. Seems obvious, right? But think about it. Food can have different meanings. Maybe you like a certain food because your grandma makes it for you, and she likes it because her grandma made it for her. Or you might like a food, and dislike others, because it has special meaning in your religion.

People also differ in HOW they taste certain foods. Some people have genes that make them SUPERTASTERS. Supertasters taste certain bitter compounds in foods (such as in Brussels sprouts) that other people don’t notice.

Also, your taste may change as you grow up. Is there something that your mom loves, but you hate? She probably thinks that you’re just being persnickety. “Just try it, you’ll like it,” right?

But according to Adam Drewnowski, who studies nutrition at the University of Washington, maybe it really DOES taste awful to you. Explain very politely to your mother that you’ve been doing some research, and that you’ve learned that maybe your taste buds haven’t matured like hers. You might even compromise and suggest that even though the broccoli tastes bitter to you, it might not taste so bad if she put a little cheese sauce on it.

Chimps Just Don’t Want to Be Human!

January 6th, 2012

Dear Dr. Universe,
Is it possible to cross a chimpanzee with a human?
Sincerely,
Dave W.

Chimpanzee mom and baby. Wikipedia

Chimpanzee mom and baby. Wikipedia

Excuse me? I suppose I’ve got the question straight, but I’m having a hard time trying to imagine my chimpanzee buddies having any desire to join the human family. No offense, but from what I’m told chimps are pretty content with how they look.

We could think about this question several different ways. The one I just referred to we could call “aesthetic.” Another is what we call “ethical.” Ethics has to do with whether something is right. And both aesthetics and ethics have something to do with the queasy feeling in your stomach about the question.

Then there’s your question: can it can be done?

So I went to ask Professor Michael Skinner. He said, “NO.”

Professor Skinner is the director of the Center for Reproductive Biology at WSU. He studies how animals reproduce, so he’s got a pretty good handle on your question. I also got the feeling he felt pretty strongly about this. So I’ll repeat his answer: “NO.”

Well, that kind of takes care of the other angles, doesn’t it?

But why not? After all, you’ve probably read that, when it comes to their genes, chimpanzees and humans are 98 or 99 percent alike.

Although humans and chimpanzees share a common ancestor, their evolution split apart millions of years ago. So the “99 percent similar” genetic makeup of humans and chimps doesn’t mean all that much.

Professor Skinner told me that the 99 percent refers only to a fairly basic comparison of proteins and not the actual “DNA sequence,” which is what really makes us what we are. In fact, scientists are busy right now trying to unravel the human DNA sequence as part of the Human Genome project.

Professor Skinner also told me that the sperm and egg from a chimp and human just wouldn’t recognize each other. Since reproduction is all about the sperm and egg getting together, this is a pretty major problem.

Within the past few years, scientists have been able to inject, with a very tiny needle, uncooperative human sperm directly into a human egg. This is called “in vitro fertilization.” But even if you tried to do this between humans and chimps, their bundles of genes, called chromosomes, wouldn’t match up.

One definition of “species,” such as humans, is that it cannot breed with another “species,” such as chimpanzees. Now, this definition doesn’t always hold up. For example, horses and donkeys can breed to make mules. But horses and donkeys are much, much closer in their ancestry than are humans and chimps. And even so, mules cannot reproduce, which means not everything between the donkey and horse matched up correctly. As Professor Skinner says, “If species COULD cross breed easily, we’d have many fewer species.”

Genetic engineers can put genes from one species into another species, but this does not make the second species part of the first. It just means the second species has some different genes.

Maybe your question comes from knowing about Oliver, the chimpanzee who lives at a place in Texas called Primarily Primates. Oliver walks upright and likes to sip beer and watch television. For these and other reasons, some people thought for a while that Oliver might be a human-chimp combination.

But recently, scientists tested Oliver’s chromosomes and found that he was indeed just a chimp. An unusual one perhaps, but a chimp. So even if chimps and humans cannot breed, Oliver has proved that chimps can develop just as bad habits as humans!

You Light Up My Life!

January 6th, 2012

My question is how or where or what organs actually produce the electric current that powers the human body? How much current is produced?
Thank You,
Jerry

Holding a lightbulb. Stephen Poff.

Stephen Poff

Didn’t somebody sing about the “body electric”? Well, sure, the poet, Walt Whitman. Check him out, Jerry. He’ll give you a different perspective on this.

But for now I guess you’re after the SCIENTIFIC explanation, right? Well, you’re right about the body being “powered” by electricity. Actually, it uses electricity to COMMUNICATE with itself. But there is no single organ in the body that produces the electricity. Rather, says Professor Steve Simasko, every cell in the body produces it. That’s right—every single cell!

Professor Simasko is a pharmacologist here at Washington State University. Pharmacologists study drugs and how they affect the body. So why, you ask, would a pharmacologist be interested in electricity?

He says a lot of drugs work because they interfere with the “channels” that carry the “ions” that help produce electricity in the cells. For example, a local anesthetic, like you get at the dentist’s, works by “blocking the ion channels and preventing pain fibers from generating electricity.” So your pain fiber never fires, and your brain feels no pain.

But maybe we need to back up a little bit. Electricity in the cells, though not nearly as strong, is the same as the electricity that lights your house. But it IS produced a little differently.

The electric current that lights your house is the flow of electrons. The electricity in your cells comes from the flow of “ions.” Ions are atoms or molecules that have an electric charge because they have either lost or gained electrons.

Like a battery, or the generators at the Grand Coulee Dam, the cells generate “potential energy” by separating electrical changes. That means the energy used to separate them will be released if they come back together. That released energy is called “voltage.”

The cells separate the charges by pumping one kind of ion through a “channel,” basically a hole, in their membranes that will only let one kind of ion through. So what you end up with is two opposite charges separated by the cell membrane.

But these opposite charges long to get back together. So when the cell needs electricity, all it needs to do is open one of these channels to complete the electrical circuit. Neat, huh?

Some cells generate more than others, says Professor Simasko. The amount depends on what the cells do and what they use the electricity for. Nerve cells and heart cells generate a lot of electricity. Nerve cells use it to transmit messages over long distances.

Suppose, for example, that you burn your finger. A nerve fiber (which is really one cell) uses electricity to send that pain signal all the way from your finger to your spinal cord. There, it makes a chemical signal to another cell, which sends another electrical signal to the brain. And there, somehow the signal gets interpreted as pain. We don’t really know exactly how that happens.

Other cells that use a lot of electricity are heart cells. They use electricity to control the beating of the heart. Endocrine cells, which Professor Simasko studies, use electricity to control how much hormone they give off.

Now, you also asked how much electricity is produced in the body. Well, the difference between the outside charge and the inside charge of a cell (what’s called the “resting potential”) is about 50 millivolts. That’s 50 x 1/1000 of a volt. Compare that to a little AAA flashlight battery, which has 1.5 volts. Not much, right? But, says Professor Simasko, add up the electricity generated by all the trillions of cells in the body and what you get is enough to light a 40 watt light bulb!

Why do we sleep? (Part 3)

September 22nd, 2011

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View Part 2: Why do we sleep?