Urea, together with water and other waste substances, forms the urine as it passes through the nephrons and down the renal tubules of the kidney. From the kidneys, urine travels down two thin tubes called ureters to the bladder. The ureters are about 8 to 10 inches long. Muscles in the ureter walls constantly tighten and relax to force urine downward away from the kidneys. If urine is allowed to stand still, or back up, a kidney infection can develop.
SAGITTARIUS (November 23-December 21) LUCKY DAY: Thursday THE per fect woman for a Sagittarian man is a Gemini - which is why Brad Pitt and Angelina Jolie are Hollywood's golden couple. Celebs with stars in their (sex) lives; New PEOPLE astrologer Claire Petulengro takes a look at what 2009 holds for some of the biggest names
For other uses, see Labor Day (disambiguation). Labor Day in the United States is a public holiday celebrated on the first Monday in September. It honors the American labor movement and the contributions that workers have made to the strength, prosperity, laws and well-being of the country. It is the Monday of the long weekend known as Labor Day Weekend and it is considered the unofficial end of summer. The holiday is also a federal holiday. Beginning in the late 19th century, as the trade union and labor movements grew, trade unionists proposed that a day be set aside to celebrate labor.