The correct answer choice that describes the path taken by excretory fluid through the mammalian kidney is as follows:
Renal artery: Excretory fluid enters the kidney through the renal artery, which supplies oxygenated blood to the organ.
Renal cortex: The renal artery branches into smaller arterioles, which lead to the renal cortex, the outer region of the kidney.
Glomerulus: Within the renal cortex, each arteriole forms a network of tiny blood vessels called the glomerulus. It is here that excretory fluid filtration occurs.
Bowman's capsule: The glomerulus is enclosed by Bowman's capsule, a cup-shaped structure that collects filtrate.
Proximal convoluted tubule (PCT): From the Bowman's capsule, the filtrate moves into the PCT, a twisted tubular structure where reabsorption of valuable substances like glucose, ions, and water occurs.
Loop of Henle: The filtrate then descends into the Henle loop, which consists of a descending limb and an ascending limb. The Henle loop plays a crucial role in concentrating urine and maintaining the balance of water and salt in the body.
Distal convoluted tubule (DCT): After the Henle loop, the filtrate enters the DCT, which further fine-tunes the reabsorption and secretion of substances based on the body's needs.
Collecting duct: The DCT connects to the collecting duct, which gathers filtrate from multiple nephrons. The collecting ducts merge and eventually lead to the renal pelvis.
Renal pelvis: The renal pelvis is a funnel-like structure that collects excreted fluid from the collecting ducts.
Ureter: From the renal pelvis, the excretory fluid flows into the ureter, a tube that transports the fluid to the urinary bladder for storage.
Urinary bladder: The urinary bladder temporarily stores excretory fluid until it is eliminated from the body through the urethra during urination.
This is a simplified overview of the excretory fluid's path in the mammalian kidney. It highlights the main structures involved in the filtration, reabsorption, and excretion processes.