What is the name of the expansion at the end of a renal tubule that receives fluid from the glomerulus?

The correct answer is the glomerular capsule, also known as Bowman's capsule. This structure is a crucial component of the nephron, the functional unit of the kidney. It is located at the beginning of the renal tubule and surrounds the glomerulus, which is a network of capillaries where blood filtration occurs.

When blood flows into the glomerulus, the pressure forces water, electrolytes, and small molecules from the blood into the glomerular capsule, forming the initial filtrate. This is the first step in urine formation, as the filtrate then passes through the renal tubule for further processing to reabsorb needed substances and secrete waste products.

The glomerular capsule plays an essential role in collecting this initial filtrate and facilitating its journey through the nephron for further processing. Understanding this structure and its function is critical for comprehending how the kidneys filter blood and maintain fluid and electrolyte balance in the body.