Final answer:
The casing around the glomerulus is known as Bowman's capsule, which is part of the renal corpuscle involved in blood filtration in the kidneys. Hence, option (a) is correct.
Step-by-step explanation:
The casing around the glomerulus is called Bowman's capsule. This structure is part of the renal corpuscle and plays a critical role in the filtration of blood in the kidneys. Within the renal corpuscle, the Bowman's capsule surrounds the glomerulus, where it collects the filtrate that has passed through the glomerulus.
This filtrate then enters the renal tubule, starting with the proximal convoluted tubule, proceeds to the loop of Henle (which includes both descending and ascending parts), continues into the distal convoluted tubule, and finally reaches the collecting ducts.
The renal cortex is the outer part of the kidney containing all of the nephrons, some of which have loops of Henle that extend into the medulla. Conversely, the collecting duct does not empty into the distal convoluted tubule; instead, the loop of Henle empties into it.