Question

Of the total nephrons, juxtamedullary nephrons constitute
A) 15%
B) 45%
C) 65%
D) 85%

Answer 1

A juxtamedullary nephron is a type of nephron whose renal corpuscle is near the medulla, and whose proximal convoluted tubule and its associated loop of Henle occur deeper in the medulla.

Complete answer:

1. Kidneys contain two types of nephrons, each located in different parts of the renal cortex: cortical nephrons and juxtamedullary nephrons.
2. Cortical nephron is a microscopic structural and functional unit of the kidney with a short loop of Henle, which penetrates only the outer renal medulla. The Malpighian corpuscles of these nephrons are located in the outer part of the renal cortex. They constitute about 85% of total nephrons in the kidney.
3. Juxtamedullary nephrons have a glomerulus near the junction of the cortex and medulla and they have loops of Henle that penetrate deep into the medulla. They constitute about 15% of the total nephrons in the kidney.

Additional information:
The functional unit of the kidney is called a nephron. Each nephron is composed of a renal corpuscle, while it's called a glomerulus within Bowman's capsule, a proximal tubule which are convoluted and straight components), an intermediate tubule (known as loop of Henle), a distal convoluted tubule, a connecting tubule, and cortical, outer medullary, and inner medullary collecting ducts.Different types of nephrons contain the various elements in different proportions.The proximal tubule consists of the proximal convoluted tubule and the proximal straight tubule. The distal tubule which consists of the distal convoluted tubule, the connecting tubule, and the initial collecting tubule.

Thus, the correct answer is option A (15%).

Note: There are on an average order of $10^6$ nephrons in a kidney. Different types of nephrons contain the various elements in different proportions.