What occurs when plasma glucose concentration exceeds the renal plasma threshold?

• A. Glucose is reabsorbed completely by the kidneys.
• B. Glucose appears in the urine, a condition known as glucosuria.
• C. The liver increases glycogen synthesis.
• D. The pancreas stops producing insulin.

Answer: (B)

Verified step by step guidance

1. Understand the concept of renal plasma threshold: This is the concentration level at which the kidneys can no longer reabsorb glucose efficiently, leading to its excretion in urine.
2. Recognize the role of the kidneys in glucose reabsorption: Normally, the kidneys filter blood and reabsorb glucose back into the bloodstream until the renal plasma threshold is reached.
3. Identify what happens when the threshold is exceeded: When plasma glucose concentration surpasses this threshold, the transport mechanisms in the kidneys become saturated, and glucose begins to appear in the urine, a condition known as glucosuria.
4. Consider the physiological implications: Glucosuria indicates that the body is unable to manage high blood glucose levels effectively, often seen in conditions like diabetes mellitus.
5. Differentiate between the options provided: The correct answer is that glucose appears in the urine, not complete reabsorption, increased glycogen synthesis, or cessation of insulin production.