**Question:** All the following are true regarding blood supply to the kidney, except

A. The renal artery branches into interlobar arteries
B. The renal vein drains blood from the kidney to the heart
C. The glomerulus is the first branch of the renal artery
D. The renal vein is responsible for delivering oxygenated blood to the kidney

**Correct Answer:** D. The renal vein is responsible for delivering oxygenated blood to the kidney

**Core Concept:** Blood supply to the kidney

The kidney is a vital organ responsible for filtering the blood and maintaining fluid and electrolyte balance in the body. It receives blood from two major vessels: the renal artery and the renal vein.

**Why the Correct Answer is Right:**

The correct answer, D, highlights the function of the renal vein in the kidney. The renal vein is responsible for collecting deoxygenated blood from the kidney and returning it to the heart to be reoxygenated. In contrast, the renal artery delivers oxygenated blood to the kidney, as explained in options A and C. The glomerulus is indeed the first branch of the renal artery (option C), but this is not relevant to the correct answer.

**Why Each Wrong Option is Incorrect:**

A. Renal artery branches into interlobar arteries: This statement is true and is relevant to the correct answer, as interlobar arteries further branch into arcuate arteries and then into efferent arterioles, which ultimately form the glomerular capillaries.

B. Renal vein drains blood from the kidney to the heart: This statement is incorrect. The renal vein collects deoxygenated blood from the kidney and returns it to the heart for reoxygenation.

C. Glomerulus is the first branch of the renal artery: This statement is true, but it is not relevant to the correct answer since the focus is on the function of the renal vein, not the renal artery.

**Clinical Pearl:**

Understanding the blood supply to the kidney is crucial for medical students and clinicians alike. The correct answer, D, helps medical students appreciate the role of the renal vein in the kidney's function and the overall blood circulation. Option C highlights the importance of the glomerulus in filtering blood, but does not address the main focus of the question. The other options (A, B, and E) are incorrect, as they emphasize the role of the renal artery and vein, not the vein.