Circulatory and Excretory system
The Circulatory System is the system by
which oxygen and nutrients reach the
body's cells, and waste materials are
carried away. Blood serves as the system
of transport. The heart, a muscular organ,
positioned behind the ribcage and between
the lungs, is the pump that keeps this
transport system moving.
What color is blood? Well, that depends. Sometimes it is red, and sometimes it is blue. Don’t believe me? Look at your arm. Better yet, look at the arm of one of your parents. Can you see the blue veins? Why are they blue? When blood is full of oxygen it is red, but when it is low on oxygen it turns bluish. Why don’t I ever see blue blood? Because as it leaves your body it quickly turns red as it takes in oxygen.
Veins are similar to arteries but, because they transport blood at a lower pressure, they are not as strong as arteries. Like arteries, veins have three layers: an outer layer of tissue, muscle in the middle, and a smooth inner layer of epithelial cells. However, the layers are thinner, containing less tissue.
The arteries are the blood vessels that deliver oxygen-rich blood from the heart to the tissues of the body. Each artery is a muscular tube lined by smooth tissue and has three layers:
- The intima, the inner layer lined by a smooth tissue called endothelium
- The media, a layer of muscle that lets arteries handle the high pressures from the heart
- The adventitia, connective tissue anchoring arteries to nearby tissues
If the excretory system stopped, your bladder would hold it in, then it would overfill and would tear. The germs will then infect your body. You wouldn't live very long. If your kidneys stopped working your Urine/Pee will turn brown. It would hurt your bladder and kidneys. Next you should go to the hospital. If you don't your kidneys would shut down.
What the Excretory system does
The excretory system rids toxic waste starting with the kidneys filtering liquid wastes from our blood then through the ureters carrying all the waste goes to the bladder for storage or release.