THE EXCRETORY SYSTEM
All of the cells in your body produce waste that cannot be used and must be eliminiated. There are four systems that eliminiate waste from your body:
Carbon Dioxide through the respiratory system
Solid waste through the digestive system
Liquid waste through the urinary system
Sweat through the integumentary system
Toxins are poisonous substances in your body. The liver first breaks down toxins in the blood, while later the kidneys will filter out additional toxins.
How does your body eliminiate liquid waste? Your bladder is the organ that holds urine before it is eliminated from the body. The bladder can hold up to one and a hlaf pints of urine at one time. When your bladder is full, it can be about the size of a grapefruit. When it is empty it is the size of a plum. The walls of the bladder are very strong and can stretch and shrink based on how much liquid it is holding.
Your kidney is an extremely important part of the excretory system. Your blood is filtered through your kidneys around 60 times a day. Make a Teaching Poster that shows an illustration of a kidney, includes important facts about kidneys, and explains how a nephon works.
Kids Biology: http://www.kidsbiology.com/human_biology/excretory-system.php
Kids Health - Your Kidneys: http://kidshealth.org/kid/htbw/kidneys.html
Yuckiest Site on the Internet: http://yucky.discovery.com/noflash/body/pg000128.html