An antibiotic is circulating through the blood when it passes through the kidneys. Only a miniscule amount of it passes through the glomerular capillary and enters the glomerular filtrate, but when its presence in the urine is measured, it has been almost completely excreted! How is this possible?
A)During the process of reabsorption, flow of water across the tubular membrane into the peritubular capillary passively encourages the antibiotic to cross the opposite way.
B)Stimulation from nerves causes the efferent arteriole to constrict and force the antibiotic through the glomerular capillary into the filtrate.
C)The antibiotic is actively transported into the proximal tubule during tubular secretion.
D)Sodium ions crossing into the blood of the peritubular capillary increases osmotic pressure and forces the antibiotic into the proximal tubule.

Question

Quizplus · Accepted Answer

The active transport of the antibiotic into the proximal tubule during tubular secretion is the most likely explanation for its almost complete excretion. Tubular secretion is a process by which substances are actively transported from the peritubular capillary into the renal tubules, allowing for the removal of waste products and certain drugs from the body. In this case, the antibiotic appears to be actively transported into the proximal tubule during tubular secretion, thereby facilitating its excretion from the body.

An Antibiotic Is Circulating Through the Blood When It Passes