Is the cortex part of kidney?

The answer is yes.

The kidney is a bean-shaped organ that is located on either side of the spine, just below the rib cage. The kidney is responsible for filtering waste products from the blood and producing urine. The kidney is divided into two main regions: the cortex and the medulla. The cortex is the outer layer of the kidney and contains the glomeruli, which are tiny filters that remove waste products from the blood. The medulla is the inner layer of the kidney and contains the tubules, which are small tubes that collect the urine and transport it to the bladder.