Final answer:
The renal sinus is a cavity within the kidney that is surrounded by the renal cortex. It contains the renal pelvis, major and minor calyxes, blood vessels, and connective tissues. It serves as the entry and exit site for structures that service the kidneys, and is filled with urine, blood vessels, and other supporting structures.
Step-by-step explanation:
The renal sinus is a cavity within the kidney that is located in the center of the kidney. It is surrounded by the renal cortex and contains the renal pelvis, major and minor calyxes, blood vessels, and connective tissues.
The renal sinus serves as the entry and exit site for structures that service the kidneys, including vessels, nerves, lymphatics, and ureters. The renal pelvis, which is formed from the major and minor calyxes, funnels urine into the ureter via peristalsis.
The renal sinus is filled with urine, blood vessels, connective tissues, and other structures that support the functioning of the kidneys.