Question

what is cortex and medula of the kidney????

Answer 1

The outer portion is dark in colour and is called renal cortex. The inner pale region of the kidney is called renal medulla.

Answer 2

Ahoy.

The cortex region of the kidney is dark in color because there are so many capillaries carrying blood such as afferent arterioles and also the presence of glomerulus adds more of the dark red color.
The medullary region has got the loop of henle, the collecting duct, some part of proximal convoluted tubule and some part of distal convoluted tubule as they are not supplied with that much blood they appear to be dull in color.