Gross Anatomy of the Excretory System
This image shows one of the two bean-shaped kidneys which lie behind the intestines, along the posterior abdominal wall. Each kidney is drained by a ureter, which carries urine to the bladder. Follow the ureter to the bladder. Notice that the bladder partly extends into the umbilical cord, and continues into the cord as the allantoic stalk. In the fetus, wastes are removed via the placenta; this connection will, of course, be lost after birth. The posterior end of the bladder leads into a narrow duct, the urethra, which carries urine to the outer surface of the body, you will follow it further when we dissect the reproductive organs.
You have already examined a slide of the kidney during the histology lab as an example of simple cuboidal epithelium, which lines the tubules. Now we will look more closely at the overall structure of this organ. The prominent rounded areas with a lighter border near the outside (cortex) of the kidney are the renal corpuscles. Examine one under high power. You should be able to see the glomerulus, or knot of capillaries, and the surrounding epithelia-lined capsule (Bowman's capsule). Throughout the remainder of the kidney you will see sections at various angles through the tubules of the kidney. Refer to your text for a diagram of one nephron, showing the arrangement of the tubules. It is schematic; you will not see a nephron like this in the section.