Final answer:
The kidneys being retroperitoneal means they are located outside the peritoneal cavity, between the parietal peritoneum and the abdominal wall. This provides them with additional protection. The kidneys are roughly the size of a fist and receive about 25 percent of the cardiac output at rest.
Step-by-step explanation:
The term 'retroperitoneal' refers to the location of the kidneys. It means that the kidneys are located outside of the peritoneal cavity, between the parietal peritoneum and the abdominal wall.
This positioning provides additional protection for the kidneys, as they are surrounded by muscle, fat, and the ribs. The kidneys are roughly the size of a fist and receive about 25 percent of the cardiac output at rest.
The retroperitoneal location of the kidneys is important in terms of understanding their anatomy and function.