A Visual Introduction to Human Anatomy

Use the Visible Body Learn Site’s text, illustrations, and animations to learn and communicate basic human biology concepts. Enjoy!

A comparison of the male and female urinary system

Filtering Blood, Removing Urine: How the Structures of the Urinary System Work

The primary structures of the urinary system include the kidneys, ureters, bladder, and urethra. Learn about the complex role of the kidneys, how urine drains into the ureters, and just how much the adult bladder can hold. Learn the main differences between the female and male urethra.

Cross section of the glomerulus, a structure of the nephron

Filtration, Reabsorption, Secretion: The Three Steps of Urine Formation

Blood and waste play a large role in the processes of filtration, reabsorption, and secretion. What’s a proximal convoluted tubule? Where does the exchange of gas, nutrients, and waste between blood and tissue take place? What does the filtration membrane do? Read on to learn about the back and forth of how urine is formed.