Anatomy and Physiology II Practice Test

Which substance is primarily reabsorbed in the proximal convoluted tubule?

1. Sodium

2. Urea

3. Glucose

4. Creatinine

The correct answer is: Glucose

The proximal convoluted tubule (PCT) plays a crucial role in the renal system, particularly in the reabsorption process that occurs after initial filtration in the kidneys. One of the primary functions of the PCT is to reclaim valuable nutrients from the filtrate that is initially formed in the Bowman’s capsule. Glucose is primarily reabsorbed in the PCT due to the presence of specialized transporters. These transporters, specifically the sodium-glucose co-transporter proteins, facilitate the movement of glucose from the tubular fluid back into the bloodstream. This process is coupled with sodium reabsorption, which is vital for maintaining the body’s energy needs and preventing loss of glucose in the urine. Other substances mentioned, such as sodium, urea, and creatinine, are also processed in the kidneys, but they do not undergo as significant a reabsorption as glucose in the PCT. Sodium is indeed reabsorbed, but it may not be the primary focus of the PCT's absorptive capacity like glucose is. Urea is partially reabsorbed but plays a role in the concentration of urine rather than as a primary nutrient. Creatinine, on the other hand, is primarily a waste product with minimal reabsorption occurring in