The urinary system includes the kidneys, bladder and tubes. These organs control the amount of water and salts that are absorbed back into the blood and what is taken out as waste. This system also acts as a filtering mechanism for the blood.

1.

Kidneys

The kidneys are a filter for the blood. The body has two kidneys located in the middle of the back at about the location of your elbows. Blood is pumped from the heart to the kidneys to be cleaned. Each kidney has about 1000 nephrons that act as filters. As the blood goes into a nephron, everything that is dissolved in the blood (waste products, food) is pushed out of the blood into small tubules. As these things travel through the tubule, the water and anything else the body needs goes back into the blood. The rest of the waste products keep moving through the tubule into the urethra. The urethra is the tube that leads to the bladder. The cleaned blood leaves the kidney and travels throughout the body.

2.

The bladder is where urine is stored to be released from the body. It can hold between one half to two cups of urine before it needs to be emptied.

Everyday about two to five cups of urine pass through the bladder.

The more water you drink, the more urine is produced. If it is hot outside and you produce a lot of sweat, you will not make as much urine.