The system that allows urine to be filtered from the blood and urine to be excreted is called the systema urinaria. The organs that make up the systema urinaria are the kidney, ureter, vesica urinaria and urethra. The most basic and functional part of the system is the kidneys. The kidneys are a pair of organs located on the posterior abdominal wall on either side of the vertebrae. The general structure of the kidney is divided into two parts, the cortex renalis and the medulla renalis. The cortex renalis contains the structures that make up the urine, while the medulla renalis consists of the collecting ducts. The urine filtered from the ren, which resembles a bean grain in shape, is transferred through the tubular ureter to the vesica urinaria, which is shaped like a sac. After the urine accumulated here reaches a certain volume, it is excreted through the urethra, which has the structure of a canal. Among domestic mammals, the organs that make up the systema urinaria are distinguished by morphological differences. The ren, which generally resembles a bean grain, has a lobed appearance in cattle, the right kidney in equids resembles a cup, and the kidney in cats is corrugated.