Kidneys and Urinary

Our bodies produce several kinds of wastes, including sweat, carbon dioxide gas, feces (stool), and urine.Urine, which is produced by the kidneys, contains the byproducts of metabolism — salts, toxins, and water — that end up in the blood.The kidneys and urinary tract (which includes the kidneys, ureters, bladder, and urethra) filter and eliminate these waste substances from our blood.Without the kidneys, waste products and toxins would soon build up in the blood to dangerous levels.
Average urine production in adult humans is about 1 – 2 L per day, depending on state of hydration, activity level, environmental factors, weight, and the individual's health.Producing too much or too little urine needs medical attention. Polyuria is a condition of excessive production of urine (> 2.5 L/day), oliguria when < 400 mL are produced, and anuria one of < 100 mL per day.
The amount of urine a person produces depends on many factors, such as the amounts of liquid and food a person consumes and the amount of fluid lost through sweat and breathing.Certain medications, medical conditions, and types of food can also affect the amount of urine produced.Children produce less urine than adults; the amount produced depends on their age.

In kids, the more common problems include:
Congenital problems of the urinary tract. As a fetus develops in the womb, any part of the urinary tract can grow to an abnormal size or in an abnormal shape or position.
Glomerulonephritis is an inflammation of the glomeruli, the parts of the filtering units (nephrons) of the kidney that contain a network of capillaries (tiny blood vessels).
High blood pressure (or hypertension) can result when the kidneys are impaired by disease.
Kidney (renal) failure can be acute (sudden) or chronic (occurring over time and usually long lasting or permanent).
Nephritis is any inflammation of the kidney.
Urinary tract infections (UTIs) are usually caused by intestinal bacteria, such as E.
Vesicoureteral reflux (VUR) is a condition in which urine abnormally flows backward (or refluxes) from the bladder into the ureters.

Wilms' tumor is the most common kidney cancer occurring in children.