Normal urine from a healthy person can be expected to contain all of the following except

A. urethra: This terminal duct of the male reproductive system serves a dual purpose by transporting both urine and semen. It is divided into prostatic, membranous, and spongy segments. As the final conduit for ejaculation, it is an essential component of the male reproductive ductal network.

B. ductus deferens: Also known as the vas deferens, this muscular tube propels sperm from the epididymis toward the ejaculatory duct during sexual arousal. It travels within the spermatic cord and enters the pelvic cavity via the inguinal canal. It represents a major segment of the internal duct system.

C. seminiferous tubules: These tightly coiled structures within the testicular lobules are the site of spermatogenesis. While they are the initial location where sperm are formed, they function as the beginning of the ductal pathway. They lead directly into the tubuli recti and the rete testis.

D. epididymis: This comma-shaped organ stores immature sperm and provides the environment for them to acquire motility and fertility. It consists of a highly coiled duct that connects the efferent ductules to the ductus deferens. It is a vital intermediary in the male reproductive tract.

E. corpus spongiosum: This is a column of erectile tissue that surrounds the spongy urethra within the penis. Its primary function is to prevent the compression of the urethra during an erection, ensuring a patent pathway for ejaculation. It is an anatomical erectile body rather than a duct.

A. the glomerular capillaries: These vessels are the site of filtration, where blood pressure pushes water and small solutes into the capsular space. They do not perform reabsorption, as the pressure gradient is directed outward into the nephron. Reabsorption is a tubular process that occurs after the fluid has left these capillaries.

B. the proximal convoluted tubule: This segment is responsible for the reabsorption of 100 percent of the filtered glucose and amino acids under normal physiological conditions. It utilizes secondary active transport via sodium-dependent symporters on the apical membrane. This high-capacity recovery ensures that essential nutrients are not lost in the urine.

C. the renal corpuscle: The corpuscle, consisting of the glomerulus and its capsule, is the site of ultrafiltration rather than reabsorption. It produces the raw filtrate that contains glucose and amino acids. The actual recovery of these substances back into the blood occurs further downstream in the specialized tubular segments.

D. the distal convoluted tubule: While this segment performs fine-tuning of water and electrolytes like sodium and calcium, it is not the primary site for nutrient reabsorption. By the time filtrate reaches the distal tubule, glucose and amino acids should have already been completely removed. Its transport capacity for these molecules is negligible.

E. the collecting duct: The primary function of the collecting duct is the final concentration of urine through the regulated reabsorption of water and urea. It does not possess the transport proteins required for glucose or amino acid recovery. These nutrients are absorbed much earlier in the nephron to maximize metabolic efficiency.