Ency123

Simply stated, the blood circulates because it is pushed by the hearth like a pump.  Arteries and veins are tubes through which the blood is delivered.  Blood flows and transports air from the lungs and nutrients from the digestive organs to other parts of the body and takes out carbon dioxide and other unnecessary substances from the tissues. Blood Vessels Blood vessels are actually two pipe systems, one of which is large and the other small. We call them big and small circulation. Both are connected with the heart, “the pump”, but these two systems are not connected. Small blood stream leads from the heart to the lungs and back, and a large from the heart goes out to the various parts of the body and back again to the heart. The three types of blood vessels are called arteries, veins and capillaries.  Arteries take the blood out of the heart, and veins return it back there. Capillaries are the network of small blood vessels, which connect the arter...

Human bones are so strong that it is a wonder that they ever break! Bone can bear a load, 30 times greater than brick can bear. What is the strongest bone in your body? The strongest bone in the body is the jaw.  It can withstand a load of 1,600 kg (3527 Pounds). However, the bone is sometimes broken by the action of strong force. Types of bone fractures Each fracture has a name, depending on how the bone was broken. If it is cracked at one part of its surface, so that its ends are still connected, then it cracks or incomplete fracture.  If the bone is completely broken in two, it's an easy or simple fracture. When the bone is broken in more than two, then it's a complex fracture.  Finally, if parts of broken bones go through the muscles and skin, it is an open fracture. Bone fracture healing process Setting parts of a broken bone is like gluing the pieces of a broken saucer. Parts of broken bones must be set next to each other so that they touch. But the...

Would not it be wonderful if people who have lost an arm or leg, or just a finger in an accident, could just grow a new one? This, unfortunately, when it comes to people, it is not possible, but there are living beings in which this is possible. The process by which living organisms restore the structure or sometimes even whole organs is called regeneration. Among living beings regeneration is quite different. For example, in some species of marine worms and star fish, a tiny fraction of the body can rebuild the whole organism. If there's only a small part, from it will grow a whole new body. On the other hand, we have a kind of regeneration that occurs in our own bodies. The surface layer of our skin is constantly wasted in the form of small pieces and replaced by other cells. Our hair and nails are refurbished. Even our permanent teeth are one example of regeneration. If the organism is more complex, and the man has a very complex organism, his ability to regenerate ...

Even before the baby is born, watching his parents, we can predict many of the biological features that it will have. This is possible because we know the laws of the legacy. Dominant and Recessive Traits For example, if one parent has brown eyes, and the other blue, the child will have brown eyes.  If both parents have blue irises, the child and parents have blue eyes. If one parent has curly hair, the child will have an equal chance of inheriting curly hair and blue to succeed. However, the laws of inheritance in man are sometimes very complex.  If the father has characteristics very different from the characteristics of the mother, then one of two opposite tendencies override other and the child will report the characteristics of one parent and not from the other. That distinction which prevails is called dominant and the other recessive or suppressed. Brown eyes are dominant hereditary qualities, and the blue recessive. That’s why the child in our example will h...

If we get thirsty and we have no opportunities to drink something, we feel such a great thirst that we forget about everything else. We are all sometimes were thirsty, but can you imagine how it feels to someone who did not drink water for days? If a person does not enter into his body any fluid for three weeks, he is sentenced to death. Simply, our bodies need to supplement their supplies of fluid, although 50 to 60 percent of its weight is water! An average adult loses during the day, about 700 g of water by sweating and excretes about 1.3 liters (0.34 gallons) through waste products. On the other hand, regardless of whether or not we are drinking, we are still taking in water in our organism. By digesting food, our organism gets almost 350 g of liquid a day.  But this process of loss and fluid intake is not sufficient for keeping water level, which is essential to our body. Why we need to drink water? Thirst is a sign that warns us that our body needs more water. ...

To live and work the human body needs energy, which is obtained by burning the food we eat. The result of the combustion of food in our body, of course, is not a big fire or heat. It's very mild, heat set correctly. In the human body there are substances that combine oxygen with fuel in a predetermined manner. What is the normal body temperature ? Human body maintains a constant temperature between 36.6 ° C and 37 ° C (98.6F), regardless of the ambient temperature.  This is accomplished through the center of the brain called “ the center for maintaining body heat ”. It actually consists of three centers: one that monitors the temperature of blood, the other, which raises the temperature of the blood when it drops - center for conducting heat, and a third that allows cooling the blood when the temperature is too high – center for cooling. What happens if the body temperature falls? Part of the nervous system to maintain body heat is encouraged to take the action. Then so...

Among the tribes of southern Africa an instrument similar to xylophone holds the chief place in festivals, and is played upon with considerable skill by many native musicians. Excerpt from: How? or, Spare hours made profitable for boys and girls by Holbrook, Kennedy Published 1887 This piano, called by them "marimba," consists of two bars of wood placed side by side ; in the most southern portions quite straight, but farther north, bent round so as to resemble half the tire of a carriage-wheel ; across these are placed about fifteen wooden keys, each of which is two or three inches broad, and fifteen or eighteen inches long, and their thickness, as in the case of the xylophone, is regulated according to the deepness of the note required. Each of the keys has a calabash beneath it ; from the upper part of each a portion is cut off to enable them to embrace the bars, and form hollow sounding-boards to the keys, which also are of different sizes, according to the note requ...