The excretory system removes waste from the body. The lungs expel carbon dioxide and the skin excretes water and salts. The main excretory organs are the kidneys, which are comprised of an outer cortex and inner medulla and pelvis. The nephrons in the kidneys act as filters to control blood composition, and urine is formed through filtration and reabsorption. Diuretics inhibit the nephron's ability to retain water, increasing the urination rate.

1. Excretory System

2. When things burn…

5. Main Excretory Organs: Kidneys

8. Nephron