The video shows a close-up of a hand holding a red marker and coloring in a diagram of the human urinary system. The diagram includes the kidneys, ureters, bladder, and urethra, with labels indicating the thick descending limb and thick ascending limb of the loop of Henle. The hand methodically colors in the diagram, starting with the kidneys and moving on to the other parts of the system. The video is shot from a top-down perspective, focusing on the hand and the diagram.