If a non-diabetic person releases glucose in the urine, it may be due to a defect in:

Options

A. Ultrafiltration
B. Selective reabsorption
C. Tubular secretion
D. Micturition

Answer

To solve the question regarding why a non-diabetic person might release glucose in their urine, we can follow these steps:

### Step 1: Understand the condition
- A non-diabetic person typically does not have elevated blood glucose levels. However, if glucose is found in their urine, it indicates an abnormality.

**Hint:** Consider what normal glucose metabolism looks like in a healthy individual.

### Step 2: Identify the potential causes
- The options provided are:
a. Ultrafiltration
b. Selective reabsorption
c. Tubular secretion
d. Micturition

**Hint:** Think about the processes that occur in the kidneys and how they relate to glucose handling.

### Step 3: Analyze the processes
- **Ultrafiltration**: This is the initial process in the kidneys where blood is filtered to form urine. It does not specifically relate to glucose handling.
- **Selective reabsorption**: This is the process where substances like glucose are reabsorbed back into the bloodstream after filtration. If there is a defect here, glucose may not be reabsorbed effectively.
- **Tubular secretion**: This involves the active transport of substances from the blood into the urine, which is not primarily responsible for glucose handling.
- **Micturition**: This is the process of urine expulsion and does not relate to glucose handling.

**Hint:** Focus on which process is responsible for reclaiming glucose after it has been filtered.

### Step 4: Conclude
- Since the presence of glucose in the urine of a non-diabetic person indicates that glucose is not being reabsorbed properly, the defect must be in **selective reabsorption**. This condition is known as renal glycosuria, where the renal tubules fail to reabsorb glucose effectively.

**Final Answer:** The correct option is **b. Selective reabsorption**.