The main structures of the cardiovascular system are the heart, arteries, capillaries and veins. The function of the heart is to pump blood through the arteries to the organs of the body. The arteries branch out into a network of capillaries that carry blood with nutrients to the cells and remove their waste products. The capillaries merge to form the veins that circulate the blood back to the heart.
The pulmonary artery carries blood from the heart to the lungs. The function of the lungs is to exchange gases. The carbon dioxide produced from carbohydrate and fat metabolism is carried in the bloodstream to the lungs where it is released to the atmosphere, and oxygen from the air is absorbed and stored in the hemoglobin of the red blood cells.
The aorta, which is the largest artery in the body, branches from the heart into the mesenteric and renal arteries that carry blood to the intestines and the kidneys, respectively. The blood in the capillaries of the intestines absorbs carbohydrates, proteins, and fats from the foods processed by the digestive system. Blood from the intestines goes to the liver via the hepatic portal vein. The liver removes toxins from the blood. In the liver, the ammonia produced from protein metabolism is combined with carbon dioxide to create urea. The blood from the liver flows back to the heart via the hepatic vein and the inferior vena cava. The kidneys remove nitrogen waste products from the blood. Uric acid from nucleic acid metabolism and urea from protein metabolism are filtered out by the kidneys and excreted in the urine. Blood from the kidneys goes through the renal vein, then to the inferior vena cava, and finally recirculates back to the heart.
Cardiovascular diseases, such as arterial plaque and hardening of the arteries, may result in heart attacks and strokes that are some of the leading causes of death. Proper diet and exercise can help to prevent cardiovascular diseases.
Applications coded for the Adobe Flash player are ubiquitous on the Internet. Many web sites exist only as flash implementations. Flash provides a rich environment that can render interactive graphics and sound. The problem with Flash is that it is controlled by a private company that cannot react to the demands of the great diversity of devices that access the Internet today. In April of 2010, Steve Jobs wrote an open letter explaining why Apple was not supporting Flash in its line of products. Among the reasons was that Flash does not perform well on mobile devices and that it is the number one reason why Mac computers crash. He also suggested that Adobe should focus more on creating great HTML5 tools which are completely open and controlled by a standards committee.
There is something magical about a pretty sunrise. It sets the mood for a wonderful day regardless of the problems that you have to face. The small picture above gives but a tiny glimpse of the beauty of the day. You get a different perspective when you actually see the beautiful colors of the sunrise across the whole horizon and you smell the crisp, fresh air. All your senses wake up. The progression of the colors as the sun relentlessly approaches the horizon is breathtaking. First you see the purples and dark reds. A few moments later, the reds turn to hues of orange that progress to yellow. When the sun finally peeks over the horizon, the whole sky is aflame with light. It is good to be alive to enjoy the beauty of nature.
Christmas is a time of the year when the family gets together to eat delicious food and celebrate. On Christmas eve, cookies and a glass of milk are placed for Santa Claus near the Christmas tree, and Santa places gifts under the tree while the children sleep.
Everybody loves pasta, and it is not hard to make your own. The pasta that you buy in the store is usually made only from flour and water. When you make your own pasta, you can make it more nutritious by adding eggs like traditional Italian pasta. You can also create fun shapes that are decorative and appetizing.
Aneurysm
Many years of robotic exploration of Mars have not produced evidence of life on the Red Planet. During the next twenty years, NASA will conduct several missions to try to determine whether life ever arose on Mars. NASA’s Mars Science Laboratory mission Curiosity rover, will launch in late 2011 and land on Mars in August 2012. The search will focus on places where there may be liquid water at sources of geothermal energy. There is great expectation that there may be Martian microbial life, but it would really be surprising to find multicellular organisms. Some scientists think that life on Earth may have had its start from microorganisms that traveled on rocks ejected from Mars after meteorite impacts. If life is found on Mars, DNA analysis will be used to identify similarities to Earth organisms.
