Table of Contents
What Is the Urinary Tract?
The urinary tract consists primarily of the kidneys. There are two kidneys, located closer to your back than your front at about waist level. The kidneys filter water and waste out of the blood and produce urine from that.
Ureters are the second part of your urinary tract. These narrow, hollow tubes carry urine from the kidneys to your bladder. The bladder is a balloon-like organ that holds urine until it is convenient for you to empty it in a process called urination.
The urethra is a narrow, hollow tube that carries urine from the bladder and outside of the body. The flow of urine is controlled by internal and external sphincter muscles. These muscles tighten or relax around the urethra, holding or releasing urine. In men, the genitals and prostate are considered part of the urinary system, the prostate surrounding the urethra. It is made up of glands which secrete a fluid that is part of semen; the prostate often becomes enlarged in older men.
Blood In Urine
Blood in urine is not always visible, and if the amount of blood is small, the urine appears normal. This is called a microscopic occurrence because the blood cells are visible only under a microscope. Typically, this is discovered when you have a urine test for another reason (not because you have noticed the blood). When there is enough blood to be visible, the urine may look pinkish, red, or smoky brown, like tea or cola, which is called gross or frank hematuria.  It takes very small amount for the blood to become visible in urine. About one-fifth of a teaspoon in a half-quart of urine will make it visible.
A trace amount of blood in urine is normal, and an average person with a healthy urinary tract excretes about one million red blood cells via urine each day. This amount of blood is not visible, and not considered hematuria.
An abnormal amount of blood in the urine can be acute, which means it is new, occurring suddenly. It could also occur as chronically, which means it is an ongoing or long-term bleeding. Acute hematuria can occur once, or it can occur many times in human life. Up to 10% of people have hematuria, and about 3% develop gross hematuria. Women develop hematuria more than men because women are more likely to suffer from urinary tract infections. Older adults, especially men, have hematuria more often than younger people. This is because they are more likely to take medications that can irritate the urinary tract, or have prostate enlargement or cancer. Macroscopic haematuria has a high diagnostic yield for urological malignancy — even 30% of patients with painless haematuria are found to have a urological malignancy.