Science Zone

Why Healing Wounds Itch?

<div xmlns='http://www.w3.org/1999/xhtml'>We are told that if a cut is itching it is healing, and that scratching itches is bad for healing, why have we evolved this tendency to cause the healing cut to itch? 
 
Answer 
There are special nerves in the skin, and this has only been discovered in fairly recent times as in the last few years, but there are itch specific nerve fibres in the skin, and their job solely is to signal to the A comparative picture of untreated 7-days-healed road rash in the form of a scar one year later. 
 
Fresh wound is on the right, and scar is on the 
left spinal cord that an area of the skin is being irritated in a way that we would perceive as itchy. 
 
Those nerve cells are activated in a number 
of ways. One of them is mechanically. So, if you have an insect crawling on you for example, the insect crawling over your skin elicits the right kind of stimulus that those nerve cells are interested in, 
and they are triggered. So you are therefore paying attention to that bit of 
skin because there might be a bug which is biting you, which might be about to give you malaria or something. 
 
So that's the first point, it’s mechanical. 
The nerve cells are also sensitive to chemicals and there are certain chemicals which when you put them in your skin, 
they're irritants. As a result, they make you think, “Oh! I've got an itchy patch of skin again.” You pay attention and you 
brush away the irritant chemical. 
 
Now when you have a wound, the wound closes by cells around the margins of the 
wound, proliferating, in other words, growing and they then migrate from the 
margins of the wound, down into the base of the wound. They actually follow the 
electrical gradient, a guy in Aberdeen discovered in the last 5 years or so that 
the inside of the wound is at a different voltage than the margin, and the cells flow down this electrical gradient, so they know where the base of the wound is. 
They then unite with their cellular counterparts, and stitch themselves into 
place. Then they start to contract, contractile filaments which pull the wound closed. 
 
So as they do that, they're eliciting a mechanical stress which the itch sensitive nerves will respond to and at the same 
time, there are various other factors which 
get released in a healing wound, chemicals which provoke healing in the wound, but also, up-regulate the activity of these itch sensitive nerves. 
 
So therefore, a wound that's closing up will feel itchy for mechanical and chemical reasons which are precisely the reasons why those nerve cells get stimulated in the 
first place. 
So that's the reason.</div>

Why Healing Wounds Itch?

We are told that if a cut is itching it is healing, and that scratching itches is bad for healing, why have we evolved this tendency to caus...

Why Snakes Don't Die of Their Own Venom

<div xmlns='http://www.w3.org/1999/xhtml'>I know if animals like 
ourselves ate food that had been poisoned, it would have an adverse effect on us but it doesn’t seem to on snakes. I know they’re not immune to their poison because they don’t use it on each other when they fight for their territory battles. 
I just wondered why that was really. 
 
The reason is that the venom snakes use is a 
protein. Proteins are made up of building blocks of what’s called amino acids. They’re the same stuff, effectively, as your Sunday roast meat. 
That means that if you were to eat them – say I ate a snake and ate the poison sacks – if I just ate it and 
it went into my digestive system the acid and the enzymes in my stomach would just be able to break down the protein so it would fall apart and it would be harmless. It’s 
only actually toxic if it gets beyond the gut and it gets into the circulation of the body. 
 
That’s why one snake could, for instance, eat another snake, and it wouldn’t 
be poisoned by it. In the same way, a person who has diabetes and needs to inject the hormone insulin. Insulin is a protein and if you were to eat it by mouth, the 
digestive tract would break it down. That’s why people have to inject insulin to make it work. 
 
So why don’t snakes poison 
themselves given they have the same toxin in their bodies. It’s exactly the same reason if for instance your pancreas makes 
a deadly cocktail of digestive juices which, if they got into your bloodstream, would 
kill you very rapidly. 
 
People who get a condition called acute pancreatitis do have a very high mortality rate. It does 
kill people because they literally eat themselves from the inside out. The reason that they don’t do that normally when you’re healthy is because the enzymes are made in cells in an inactive state. 
 
They’re exported from the cell into a duct which is 
lined with specially protecting cells that 
stop it going back in to the body’s own tissues and do any damage. 
The only place it can go is down the duct and then out 
into the digestive tract. 
 
If you put that into the context of the snake, it’s got a gland which knows how to make the proteins in the venom. They get exported into this duct which is a special holding 
bay, protected from the venom. 
It can’t go back the wrong way. When the snake bites 
you there are tiny muscle cells around those ducts and it squirts the venom down the fang (there’s a duct in there) and in to 
the holes that the teeth have made in you. 
 
That’s why the snake doesn’t die from its 
own venom because it keeps it in a specially adapted part of the body so it can’t get into the circulation. 
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Why Snakes Don't Die of Their Own Venom

I know if animals like ourselves ate food that had been poisoned, it would have an adverse effect on us but it doesn’t seem to on snakes. I...

10 Things You Need To Know About Your Brain

<div xmlns='http://www.w3.org/1999/xhtml'><head>The Brain</head> 
 
The human brain is the most complex and least understood part of the human anatomy. There may be a lot we don’t know, but here are a few interesting facts that we’ve got covered. 
 
1. Nerve impulses to and from the brain travel as fast as 170 miles per hour: 
Ever wonder how you can react so fast to things around you or why that stubbed toe hurts right away? It’s due to the super-speedy movement of nerve impulses from your brain to the rest of your body and vice versa, bringing reactions at the speed of a high powered luxury sports car. 
 
2. The brain operates on the same amount of power as 10-watt light bulb: 
The cartoon image of a light bulb over your head when a great thought occurs isn’t too far off the mark. 
Your brain generates as much energy as a small light bulb even when you’re sleeping. 
 
3. The human brain cell can hold 5 times as much information as the Encyclopedia Britannic Or any other encyclopedia for that matter: 
Scientists have yet to settle on a definitive amount, but the storage capacity of the brain in electronic terms is thought to be between 3 or even 1,000 terabytes. The National Archives of Britain, containing over 900 years of history, only takes up 70 terabytes, making your brain’s memory power pretty darn impressive. 
 
4. Your brain uses 20% of the oxygen that enters your blood stream: 
The brain only makes up about 2% of our body mass, yet consumes more oxygen than any other organ in the body, making it extremely susceptible to damage related to oxygen deprivation. So breathe 
deep to keep your brain happy and swimming in oxygenated cells. 
 
5. The brain is much more active at night than during the day: 
Logically, you would think that all the moving around, complicated 
calculations and tasks and general interaction we do on a daily basis during our working hours would take a lot more brain power than, say, lying in bed. Turns out, the opposite is true. When you turn off your brain turns on. Scientists don’t yet know why this is but you can thank the hard work of your brain while you sleep for all those pleasant dreams. 
 
6. Scientists say the higher your I.Q. the more you dream: 
While this may be true, don’t take it as a sign you’re mentally lacking if you can’t recall your dreams. Most of us don’t remember many of our dreams and the average length of most dreams is only 2-3 seconds–barely long enough to register. 
 
7. Neurons continue to grow throughout human life: 
For years scientists and doctors thought that brain and neural tissue couldn’t grow or regenerate. While it doesn’t act in the same manner as tissues in many other parts of the body, neurons can and do grow throughout your life, adding a whole new dimension to the study of the brain and the illnesses that affect it. 
 
8. Information travels at different speeds within different types of neurons: 
Not all neurons are the same. There are a few different types within the body and transmission along these different kinds can be as slow as 0.5 meters/sec or as fast as 120 meters/sec. 
 
9. The brain itself cannot feel pain: 
While the brain might be the pain center when you cut your finger or burn yourself, the brain itself 
does not have pain receptors and cannot feel pain. That doesn’t mean your head can’t hurt. The brain is surrounded by loads of tissues, nerves and blood vessels that are 
plenty receptive to pain and can give you a pounding headache. 
 
10. 80% of the brain is water: 
Your brain isn’t the firm, gray mass you’ve seen on TV. Living brain tissue is a squishy, pink and jelly-like organ, thanks to the loads of blood and high water content of the tissue. 
So the next time you’re feeling dehydrated get a drink and keep your body hydrated. 
 
Credit: <a href=' http://icantseeyou.typepad.com'>ICan't See You</a></div>

10 Things You Need To Know About Your Brain

The Brain The human brain is the most complex and least understood part of the human anatomy. There may be a lot we don’t know, but here a...

Skin As Body Temperature Regulator

<div xmlns='http://www.w3.org/1999/xhtml'>The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in the body. It does live up to its status by carrying out numerous functions such as protection, excretion, storage of food, sensitivity, regulation of the body temperature, production of vitamin D through the early sunshine and so on. 
 
Today we are going to see how the skin regulates the body temperature especially in we homoiothermic animals; animals with constant body temperature. 
 
This is truly amazing as how the skin keeps the body temperature constant regardless of changes in external environment though the liquid tissue cell (blood) also plays a role at body temperature regulation. 
 
On a hot day or weather, there's usually an increase in the temperature of the environment and the skin carry out the following processes to get rid of excess heat and thus to keep the body temperature constant. 
 
VASODILATION: 
There is a dilation of the capillaries near the skin surface and a constriction of those in the deeper layer. The impact of this is a large volume of blood flow close to the surface of the skin such that there's a loss of heat via the three mood of heat transfer namely; conduction, convection and radiation. 
 
DECREASE IN METABOLIC RATE: There is a reduction in metabolic activity by the skin or body and this reduces the heat released by metabolic activity and thus heat production is reduced. 
 
LOWERING OF HAIRS: We usually notice that the hairs especially those on the hands and legs rise and fall. Yes they rise and fall. 
During hot days, the hair erector muscles relax causing the hairs to lie flat on the skin surface. This expose most of the air trapped by the hairs and also heat from the body is lost as the air evaporates. 
 
SWEATING: 
The sweat gland is usually active during hot periods and there's large sweat production. As the sweat evaporate from the skin, latent heat of evaporation is also extracted from the body hence the heat of the body is reduced. 
 
On a cold day or weather, the following processes are done by the skin to regulate the body temperature. 
 
RAISING OF THE HAIRS: 
The hair erector muscle contract to raise the hair and trap more air during a cold weather. Since air is a bad conductor of heat, the layer of air next to the skin acts as an insulator and prevent heat loss from the body and conserves the normal body temperature. 
 
VOSOCONSTRICTION: There's constriction of capillaries close to the skin surface and also a dilation of capillaries in deeper layer of the skin. This brings about small volume of blood flow near the skin surface and hence prevents loss of heat and conserves body heat or temperature. 
 
INCREASE IN METABOLIC ACTIVITY: The skin increases the metabolic activity of the body especially the respiratory activity of the liver that release large amount of energy and heat. This help to generate the heat necessary to keep the body's temperature from dropping during cold weather. 
 
SWEATING: 
THE sweat gland become inactive on a cold day and hence there is very little production of sweat that gets evaporated thereby conserving the latent heat of vaporization and rather use it to keep the body temperature constant by ensuring no drop 'in temperature rate throughout the body. 
This is the very reason</div>

Skin As Body Temperature Regulator

The skin as we all know is the largest organ in the body. Also with exception of the bones and cartilages, it's the toughest tissue in t...

This Friday, There Would Be a Blue Moon

<div xmlns='http://www.w3.org/1999/xhtml'>This Friday, there will be a once in a blue moon occurrence. If you step outside, you might find yourself gazing out at a brimming, full moon. 
 
Disappointingly, it won't actually be blue; the term is a misnomer. In fact, a blue moon isn't any different to any other full moon. 
In the past, a blue moon was used to mean "rare," but now the name is given to any full moon that is the second to appear in one calendar month. The lunar cycle is around 29 
and a half days, and months of the year are between 28 and 31 days long. The probability of a full lunar cycle, from full moon to full moon, 
occurring precisely during this time window is therefore not very high. 
 
The next blue moon, by this definition, is going to be on January 31, 2018 – around two and a half years from now. There will be another blue moon two months after that on March 31, 2018, 
after which it will be another two-year wait. 
 
The term "blue moon" has evolved over the last 200 years or so. Initially, a blue moon was 
based on a complicated combination of. circumstances. In one astronomical season, there are normally three full moons and if there was ever a fourth, then that would be the blue moon. 
 
However, this all changed when a hobby astronomer, James Hugh Pruett, wrote an article that was published in the magazine <a href='http://skyandtelescope.com'> 
Sky and Telescope</a> in 1946. He defined a blue moon as any second full moon in a calendar month. 
 
This definition was incorrect, but it was so much easier to understand that the world scrambled to embrace this new definition. 
 
You might be feeling a little disheartened that the moon won't be blue, but blue moons in terms of color have been seen in the past under very special circumstances. 
 
Usually, these moons are reported after a volcanic eruption or even a forest fire, which release plumes of 
particles that rise into the atmosphere. The particles happen to be the perfect size to scatter away red light, only allowing blue light through the dust cloud. Out of the ashes, a blue moon appears. 
 
<a href='http://ifls.com'>IFLS</a> 
 
<a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKGRTmy_u8KSJzUAtSdW5q30iZoqGI3Rbtj_xP7kFiQ7yCeDaWQABw-k6BYNx6OkPX3MTEcuW98Df4GnI6YwdwAfv7SBZ2zYDxWjvnbj5zl_E97zo2us2WRb3dfCRAGEShxSn97qMIVe4/s2560/1438329660547.jpeg' onblur='try {parent.deselectBloggerImageGracefully();} catch(e) {}'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKGRTmy_u8KSJzUAtSdW5q30iZoqGI3Rbtj_xP7kFiQ7yCeDaWQABw-k6BYNx6OkPX3MTEcuW98Df4GnI6YwdwAfv7SBZ2zYDxWjvnbj5zl_E97zo2us2WRb3dfCRAGEShxSn97qMIVe4/s350/1438329660547.jpeg" style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;"/></a></div>

This Friday, There Would Be a Blue Moon

This Friday, there will be a once in a blue moon occurrence. If you step outside, you might find yourself gazing out at a brimming, full moo...

What is Dark Energy?

Instead of pulling galaxies in our universe together, gravity seems to be driving them apart. 
How can gravity be repulsive, when our everyday experience shows it’s attractive? 
 
To explain it, we need dark energy. 
 
What goes up must come down… right? 
 
How do we think about something we can't see and don’t experience in our everyday lives, but seems to be pushing our universe apart ever faster? 
 
The nature of dark energy is one of the most important unsolved problems in all of science. 
But what, exactly, is dark energy, and why do we even believe that it exists? 
Step back a minute and consider a more familiar experience: what happens when you toss a ball 
straight up into the air? 
 
It gradually slows down as gravity tugs on it, finally stopping in mid-air 
and falling back to the ground. Of course, if you threw the ball hard enough (about 25,000 miles 
per hour) it would actually escape from the Earth entirely and shoot into space, never to return. 
 
But even in that case, gravity would continue to pull feebly on the ball, slowing its speed as it escaped the clutches of the Earth. 
 
But now imagine something completely different. 
Suppose that you tossed a ball into the air, and instead of being attracted back to the ground, the ball was repelled by the Earth and blasted faster and faster into the sky. 
 
This would be an astonishing event, but it’s exactly what astronomers have observed happening to the 
entire universe! 
Scientists have known for almost a century that the universe is expanding, with all of the galaxies 
flying apart from each other. And until recently, scientists believed that there were only two possible options for the universe in the future. It could expand forever (like the ball that you tossed upward at 25,000 miles an hour), but with the expansion slowing down as gravity 
pulled all of the galaxies toward each other. 
 
Or gravity might win out in the end and bring the expansion of the universe to a halt, finally collapsing it back down in a “big crunch,” just 
like your ball plunging back to the ground. 
 
This illustration shows abstracted ‘slices’ of space at different points in time as the universe expands. 
 
So imagine scientists’ surprise when two different teams of astronomers discovered, back in 1998, that neither of these behaviors was 
correct. 
 
These astronomers were measuring how fast the universe was expanding when it was much younger than today. 
 
But how could they do this without building a time machine? 
Luckily, a telescope is a time machine. 
 
When you look up at the stars at night, you aren’t seeing what they look like today – you’re seeing light 
that left the stars a long time ago – often many hundreds of years. 
 
By looking at distant supernovae, which are tremendously bright 
exploding stars, astronomers can look back hundreds of millions of years. They can then measure the expansion rate back then by 
comparing the distance to these far-off supernovae with the speed at which they are flying away from us. 
 
And by comparing how fast the universe was expanding hundreds of millions of years ago to its rate of expansion today, these astronomers discovered that the expansion is 
actually speeding up instead of slowing down as everyone had expected. 
 
What pushes galaxies like these in the Hubble deep field apart? 
Instead of pulling the galaxies in the universe together, gravity seems to be driving them apart. 
But how can gravity be repulsive, when our everyday experience shows that it’s attractive? 
 
Einstein’s theory of gravity in fact predicts that gravity can repel as well as attract, but only under very special circumstances. 
Repulsive gravity requires a new form of energy, dubbed “dark energy,” with very weird properties. 
Unlike ordinary matter, dark energy has negative pressure, and it’s this negative pressure that makes gravity repulsive. (For ordinary matter, gravity is always attractive). 
 
Dark energy appears to be smoothly smeared out through the entire universe, and it interacts with ordinary matter only through the action of gravity, making it nearly impossible to test in the laboratory. 
 
Scientists used to think that the expansion of the universe was described by the yellow, 
green, or blue curves. But surprise, it’s actually the red curve instead. 
 
The simplest form of dark energy goes by two different names: a cosmological constant or 
vacuum energy. Vacuum energy has another strange property. Imagine a box that expands as the universe expands. The amount of matter in 
the box stays the same as the box expands, but the volume of the box goes up, so the density of matter in the box goes down. In fact, the density of everything goes down as the universe expands. 
 
Except for vacuum energy – its density stays exactly the same. (Yes, that’s as bizarre as it sounds. It’s like stretching a string of taffy 
and discovering that it never gets any thinner). 
 
Astronomers continue to probe the skies, looking for finer details that can build on what we suspect about dark energy. 
Since dark energy can’t be isolated or probed in the laboratory, how can we hope to understand exactly what it’s made of? 
 
Different theories for dark energy predict small differences in the way 
that the expansion of the universe changes with time. 
 
Credit: www.earthsky.org 
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What is Dark Energy?

Instead of pulling galaxies in our universe together, gravity seems to be driving them apart. How can gravity be repulsive, when our everyd...

Weird Facts About Human Body

<div xmlns='http://www.w3.org/1999/xhtml'>> Men lose about 40 hairs in a day and women lose 70 hairs in a day. 
 
> Your blood has same amount of salts in it as an ocean has. 
 
> You are taller in the morning than you are at night. 
 
> Heart circulates blood in your body about 1000 times each day. 
 
> Eyelashes last about 150 days. 
 
> There are 500 hairs in an eyebrow. 
 
> The average human body contains 
approximately 100 billion nerve cells. 
 
> It is not possible to sneeze with open eyes. 
 
> Bones are 4 times stronger than concrete. 
 
> Average life span of a taste bud is only 10 days. 
 
> You are born without knee caps and they don't appear until age of 2 to 6 years. 
 
> Children grow faster in springtime. 
 
> Eyes stay the same size throughout life but nose and ears never stop growing. 
 
> We born with 300 bones but end up with 206 bones when we are adult. 
 
> Human skull is made up of 26 different bones. 
 
> Hair is made of same substance as fingernails. 
 
> Our entire body functions stop when we sneeze, even your heart beat. 
 
> Tongue is the strongest muscle in human body. 
 
> Typical person goes to bathroom six times a day. 
 
> Food takes 7 seconds to reach stomach from mouth. 
 
> Children have more taste buds than adults. 
 
> Sneeze blows air out of nose at the speed of 100 miles per hour. 
 
> Largest muscle in your body is one on which you are sitting on. 
 
> Smallest bone of body is in ears. 
 
<a href='https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrJgWv_hgqA1AQDLySP4WwR9i3QQ3NrgNiY0RPG_R6FmKHBv68BmF1YPZLM-i4__-TA3zcHf8MF9Bpv8pnKZDy8qhMI92q_7Ovgso4Zerbz6Pao3SLtgJIcOxolaZZS0FVcAbsvnnquqk/s2560/1434967966575.jpeg' onblur='try {parent.deselectBloggerImageGracefully();} catch(e) {}'><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrJgWv_hgqA1AQDLySP4WwR9i3QQ3NrgNiY0RPG_R6FmKHBv68BmF1YPZLM-i4__-TA3zcHf8MF9Bpv8pnKZDy8qhMI92q_7Ovgso4Zerbz6Pao3SLtgJIcOxolaZZS0FVcAbsvnnquqk/s350/1434967966575.jpeg" style="display:block; margin:0px auto 10px; text-align:center;cursor:pointer; cursor:hand;"/></a></div>

Weird Facts About Human Body

> Men lose about 40 hairs in a day and women lose 70 hairs in a day. > Your blood has same amount of salts in it as an ocean has. ...