Final answer:
The ureter penetrates the kidney at the renal hilum, which is the area where structures such as vessels and ureters enter and exit the kidney.
Step-by-step explanation:
The ureter penetrates the kidney at the renal hilum. This area serves as the crucial entry and exit site for structures that service the kidneys, which include vessels, nerves, lymphatics, and the ureters themselves. The renal hilum is located where the medial-facing hila are nestled into the sweeping convex outline of the kidney's cortex. From the renal hilum, the renal pelvis emerges, which is formed from the major and minor calyxes. This renal pelvis then narrows down to become the ureter of each kidney, facilitating urine's transport from the kidney to the bladder through peristaltic movements.