Question

Which of the following is a part of the renal pyramid
(a) Peritubular capillaries
(b) Convoluted tubules
(c) Collecting duct
(d) All of the above

Answer 1

 
Hint: The medulla is divided into conical masses known as the renal pyramid. Since it lies in the medullary region it consists of the tubules that transport urine to the urinary bladder. Since the pyramids are living tissues, they also have blood supplies from the interlobular arteries.

Complete Step by Step Answer: The medulla is divided into a few conical masses projecting into the calyces known as medullary pyramids or renal pyramids. These medullary pyramids contain all the contents of the medulla i.e., transporting tubules like PCT, DCT, and the collecting ducts. It also gets its blood supply from interlobular arteries which divide into the smaller capillaries called peritubular capillaries to form a meshwork of a rich network of blood supply.

So, the correct answer is, “All of the above.”

Additional Information: Inner to the hilum is a broad funnel- shaped space called the renal pelvis with the projection called calyces. The outer layer of the kidney is the tough capsule. Inside the kidney, there are two zones: Renal cortex and renal medulla. Renal pyramids are triangular with its broad base towards the cortex. Apex is pointed and is called the renal papilla. It constitutes the medulla and inner substance of the kidney. There is a sieve- like appearance on the surface of the papilla. The duct of Bellini, in the opening that is present in which collecting tubules within the pyramid converge.

Note: - 1-3 renal papilla project into a cavity called the minor calyx, which joins up and forms major calyces. - There is muscle fiber attachment from the calyx to the papilla of the renal pyramid. The urine flows from the Duct of Bellini to the calyx when these muscle fibers contract. - The cortex extends in between the medullary pyramids as renal columns called Columns of Bellini. - The blockage of an artery or capillary in the renal pyramid may lead to its degeneration. - Animals like rabbits have only one renal pyramid in each kidney whereas humans have dozens of them in each kidney.