Gotta Go!
Have you ever had to use the bathroom really badly? Have
you squirmed around, trying to hold it in? You feel like this
because your body has made a large amount of urine. Before
you can feel better, you have to urinate, or let it out!
Urine contains wastes from inside your body. Wastes are
materials your body doesn’t need. Your cells are always busy
doing different jobs to keep you alive and healthy. When
your cells work, they produce things you need. But they also
produce waste. This waste is carried away from the cells in
your blood.
In order to stay healthy, your body has to excrete wastes, or
let them out of your body. This is the job of the excretory
system. The excretory system has organs that help remove
wastes. These organs include the kidneys, bladder, skin,
and lungs.
The kidneys remove waste from the blood. They make urine
from the waste and water. The bladder stores urine from the
kidneys. When your bladder is full, it feels like you need to
urinate. You have a special muscle that keeps the urine
inside your bladder. When you relax it, urine can leave your
body.
Your kidneys and bladder help
remove urine from your body.
Not all wastes from your cells leave the body as urine. When
you breathe in, you take oxygen into your lungs. When your
cells use oxygen, they produce carbon dioxide waste. Your
blood carries carbon dioxide back to your lungs. When you
breathe out, you release carbon dioxide.
Your blood also delivers some waste from your cells to your
skin. Under your skin, there are places where waste mixes
with water to make sweat. You get rid of sweat through your
skin.
You get rid of wastes by sweating, urinating, and breathing.
Your body loses liquid when it gets rid of wastes. So don’t
forget to drink plenty of water to help your excretory system
do its job!
Discovery Education Science
Your excretory system needs
water to help it get rid of
wastes.
© 2007 Discovery Communications, LLC