## **Core Concept**
The first urge to micturate is primarily mediated by the **stretch receptors** in the bladder wall. As the bladder fills, these receptors are activated, sending signals to the spinal cord and brain, indicating the need to urinate. This process involves both the autonomic nervous system and the somatic nervous system.

## **Why the Correct Answer is Right**
The correct answer, **150-200 ml**, is the volume at which the first urge to void is typically felt. This is because at this bladder volume, the stretch receptors in the bladder wall are activated, transmitting signals through the pelvic nerves to the spinal cord and then to the brain, creating the sensation of a full bladder and the urge to urinate.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it suggests a much higher volume than what is typically associated with the first urge to micturate.
- **Option B:** Similarly, this option suggests an even higher volume, beyond the typical range for the first urge.
- **Option D:** This option suggests a much lower volume than what is generally accepted for the first urge to void.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the normal adult bladder can hold up to 400-600 ml of urine. The first urge to void is usually felt at around **150-200 ml**, a strong desire to void at **400 ml**, and a sense of urgency at **600 ml**. This knowledge helps in understanding bladder capacity and function.

## **Correct Answer:** . **150-200 ml**