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
Is Lucky Blue Smith the Justin Bieber of modeling? Meet the 16-year-old Mormon with nearly one million Instagram followers. Standing at 6ft-3in with piercing blue eyes, it's not hard to see why the Mormon male model Lucky Blue Smith has more than 830,000 Instagram followers. But his thousands of crazed fans, many of whom post images of Smith on their own Instagram accounts daily, will have to contend with admiring from afar.