The main function of the renal pyramids of the kidney is to:

The total number of minor calyces in a human kidney is equal to the number of:

The notch on the medial side of the kidney is known as the ........

Given below are two statements:
Statement $I$: At the base of the urinary bladder,there is an inverted triangular area called the trigone.
Statement $II$: Three layers of dartos tunic muscles are present in the wall of the urinary bladder.
In the light of the above two statements,choose the correct option.

The afferent and efferent arterioles are . . . . . . .

Name the following:
Cortical portions projecting between the medullary pyramids in the human kidney.