My Science School

Intestines are organs, or body parts, that are shaped like long tubes. They help break down food so that the body can use it for energy. This is part of the process called digestion. The intestines also remove wastes from the body. Mammals, birds, reptiles, amphibians, and fish have intestines.

A human’s intestines fill much of the middle part of the body below the rib cage. The intestines are divided into two main sections, the small intestine and the large intestine. The small intestine is 22 to 25 feet (6.7 to 7.6 meters) long and coils like a maze. The large intestine is 5 to 6 feet (1.5 to 2 meters) long. The intestines have a special kind of muscle that squeezes and relaxes in a wavelike motion. This motion pushes food and waste through the intestines.

 The bulk of food digestion takes place in your small and large intestines. Two tubes that absorb all the vitamins, minerals, and other nutrients from everything you eat.

 

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Your skin’s all over you. In fact, your skin is larger than any other part of your body. It’s a good thing too. Your skin keeps your insides in. It keeps germs and yucky things out. It protects your body and keeps it from drying out. Skin can also help keep you cool during hot weather and warm during cold weather. Without your skin, you’d be a mess! Skin is made up of two layers. The epidermis is the outside part of the skin. It has sweat pores and hairs. The inside of the skin is the dermis. This layer has nerves, or receptors, that detect pain or touch. It also has blood vessels, oil glands and hair roots. Underneath this layer is a thin layer of fat that cushions your body. Skin holds your insides in and protects your tissues from ultraviolet radiation from the outside. Skin is your body’s largest organ. It is made of layers of cells that march to the surface and flake off from friction. The outermost layer is entirely dead.

 

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The stomach is part of the digestive system. It is an internal organ between the oesophagus and the small intestine. The stomach is the third stage in the digestive process. It holds food after ingestion. Food in the stomach then passes through to the small intestine where most of the food's nutrition is absorbed.

The stomach contains hydrochloric acid made by stomach cells. As a useful side-effect, the acid kills bacteria in the food. However, its main function is to help the protein-digesting enzymes called proteases work. In general, the food is churned, squeezed and mixed. This prepares it for digestion. The partially digested food is called chyme.

 

The stomach acid may cause problems. It can make peptic ulcers worse. It can also cause heartburn—pain in the chest when acid from the stomach refluxes (backs up into) the oesophagus. These can usually be treated by neutralizing the acid. Vomiting occurs when food goes back up the oesophagus and out the mouth. Vomiting can be a symptom of disease.

Stomachs of other mammals work differently to human stomachs. Ruminants, for example, have a stomach with multiple compartments. In that system, food goes through the first part of the digestive system twice, and the work of digesting the grass is done by bacteria.

 

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Your lungs are in your chest, and they are so large that they take up most of the space in there. You have two lungs, but they aren't the same size the way your eyes or nostrils are. Instead, the lung on the left side of your body is a bit smaller than the lung on the right. This extra space on the left leaves room for your heart.

Your lungs are protected by your rib cage, which is made up of 12 sets of ribs. These ribs are connected to your spine in your back and go around your lungs to keep them safe. Beneath the lungs is the diaphragm, a dome-shaped muscle that works with your lungs to allow you to inhale (breathe in) and exhale (breathe out) air.

You can't see your lungs, but it's easy to feel them in action: Put your hands on your chest and breathe in very deeply. You will feel your chest getting slightly bigger. Now breathe out the air, and feel your chest return to its regular size. You've just felt the power of your lungs!

 

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Your heart is really a muscle. It's located a little to the left of the middle of your chest, and it's about the size of your fist. There are lots of muscles all over your body — in your arms, in your legs, in your back, even in your behind.

But the heart muscle is special because of what it does. The heart sends blood around your body. The blood provides your body with the oxygen and nutrients it needs. It also carries away waste.

Your heart is sort of like a pump or two pumps in one. The right side of your heart receives blood from the body and pumps it to the lungs. The left side of the heart does the exact opposite: It receives blood from the lungs and pumps it out to the body.

 Before each beat, your heart fills with blood. Then its muscle contracts to squirt the blood along. When the heart contracts, it squeezes — try squeezing your hand into a fist. That's sort of like what your heart does so it can squirt out the blood. Your heart does this all day and all night, all the time. The heart is one hard worker!

 

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Yes, all of them do, actually. And not just animals. Every living thing on Earth-including single-celled bacteria, trees and plants – has DNA in its cells. You might expect to share many genes with a chimpanzee or bonobo, our closest living relatives, but did you know also share genes with that banana the chimp is chomping?

 

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Everything you see in the mirror- from your height to your hair colour to the dimple (or lack thereof) on your chin – is written into nearly every cell of your DNA, spiraling chains of proteins found in every cell in your body. Think of DNA as your body’s instruction manual. It tells your cells how to grow into organs, hair, teeth, fingernails, your tongue, and every single other part of your body. Stretches of DNA (called genes) are like pages in that instruction manual. Genes control what you will look like, plus less obvious traits such as whether you have perfect vision or the ability to curl your tongue.

 

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The skunk is a mammal primarily known for secreting a foul, noxious-smelling oily liquid from its anal glands and spraying it from its rear end when it feels threatened. Also known as polecats, skunks are classified in the Mephitidae family (or ‘skunk family’), which is in the order Carnivora. There are 12 known species of mephitis, most of which are found in the Western hemisphere (especially in the Americas).

Skunks come in a variety of sizes; they range from 15 to 37 inches long, 15 to 28 inches tall, and weigh between 0.5 and 8.2 kilograms (1.1-18 lbs). Their bodies are moderately elongated and consist of well-muscled legs. Skunks usually have long front claws that help them to dig.

Skunks reek because they have glands in their butts loaded with an icky musk. Skunk spray smells so bad because it consists of a mixture of chemicals containing sulfur (such as thiols), which are notorious for their pungent and nauseating odor, basically like the smell that rotten eggs have.

Many creatures of the animal kingdom are quite popular/notorious among humans for a variety of reasons: lions are known for their loud, thunderous roar, ostriches are known for burying their heads in the sand when they sense danger (which, by the way, is a myth), and skunks are known for their signature stinky spray. This spray is released from a skunk’s anus, and is notorious for its incredibly disgusting odor.

 

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Snot gets it’s yellow (and eventually green) color a chemical in your white blood cells, which your body unleashes to fight infection. Yellow mucus is a sign that whatever virus or infection you have is taking hold. The good news? Your body is fighting back. The yellow color comes from the cells — white blood cells, for example — rushing to kill the offending germs. Once the cells have done their work, they’re discarded in your snot and tinge it a yellowish-brown.

Your illness may last anywhere from 10 to 14 days, but keep an eye on your nasal discharge.

If your immune system kicks into high gear to fight infection, your snot may turn green and become especially thick. The color comes from dead white blood cells and other waste products.

But green snot isn’t always a reason to run to your doctor. In fact, some sinus infection may be viral, not bacterial.

Still, if you’ve had your cold or infection for 12 days or more, it may be a good time to make an appointment. You may have a bacterial sinus infection or another bacterial infection that requires medication. Look for other signs you’re not getting better, like fever, headache, or nausea.

 

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The sky is blue because air molecules in our atmosphere filter blue light out of the colour spectrum. A clear cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more than they scatter red light.  When we look towards the sun at sunset, we see red and orange colours because the blue light has been scattered out and away from the line of sight. The white light from the sun is a mixture of all colours of the rainbow.  This was demonstrated by Isaac Newton, who used a prism to separate the different colours and so form a spectrum.  The colours of light are distinguished by their different wavelengths.  The visible part of the spectrum ranges from red light with a wavelength of about 720 nm, to violet with a wavelength of about 380 nm, with orange, yellow, green, blue and indigo between.  The three different types of colour receptors in the retina of the human eye respond most strongly to red, green and blue wavelengths, giving us our colour vision.

 

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Everyone’s blood contains the same basic stuff, but mixed in with that stuff are ‘’antigens’’. These special proteins act like an ID tag for a person’s own and not a foreign invader. Antigen combinations make different blood types – eight in all – which are passed along from parent to child just like eye color and other genetic traits. If you get in an accident and lose a lot of blood (or get sick and need a fresh supply), you’ll have to go to the hospital to get a ‘’transfusion’’ of someone else’s red stuff. Transfusions are simple procedures and the most common type of hospital procedure but they always start with the doctor determining the patient’s blood type. If you get a transfusion of the wrong type, your immune system will think it’s an infection and go on the attack!

 

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Remove all your bones – along with the joints and muscles pinned to them – and you’d end up a shapeless, motionless bag of blood and organs. Your skull and spinal vertebrae, made of tough deposits of calcium and other minerals, are like armor for your brain  and nervous system. Special bone marrow in your vertebrae  and elsewhere is your body’s blood factory. Your muscles and joints, meanwhile, set your human machine in motion.

 

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A mix of special cells and liquid ‘’plasma,’’ blood delivers all the good stuff (oxygen vitamins, minerals, and chemicals called hormones) to the cell in your body and carries away all the bad stuff (carbon dioxide and other waste) for disposal. Red blood cells transport oxygen, while white blood cells fight infection. Special cells called platelets seal the leak when blood vessels break – a process called clotting. An oxygen-carrying protein called hemoglobin is what gives blood its red color.

 

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You can’t always guess a child’s appearance just by looking at his or her parents. The study of genes – called genetics – is achieving breakthroughs all the time, but much about heredity remains mysterious. Combinations of genes can affect other genes, leading to unpredictable characteristics or features that lurk in the genetic background for several generations. Our genes are riddled with so-called junk DNA that doesn’t seem to express itself in any noticeable way. Environment and diet also play a large role in shaping a person’s weight, skin tone, and other physical characteristics.

 

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While you admire your good looks in the mirror, don’t forget to thank your parents. Genes come in pairs: one from Mom and other from Dad. It’s the combination of genes that bring about – or ‘’express’’ – various physical traits (in a process called heredity). Some genes are more influential on your appearance than others. The genes for dark hair are dominant over the genes for red and blond hair, making dark hair more common.

 

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