Parasympathetic activity during micturition causes `:-`

Options

A. Contraction of detrusor muscle and contraction of internal urethral sphincter
B. Contraction of detrusor muscle and relaxation of internal urethral sphincter.
C. Relaxation of detrusor muscle and relaxation of internal urethral sphincter
D. Relaxation of detrusor muscle and contraction of internal urethral sphincter

Answer

### Step-by-Step Solution:

1. **Understanding Micturition**:
- Micturition is the process of urine release from the urinary bladder through the urethra to the outside of the body.

2. **Role of the Parasympathetic Nervous System**:
- During micturition, the parasympathetic nervous system is activated. This system is responsible for stimulating bodily functions that occur when the body is at rest.

3. **Muscle Involvement**:
- The key muscles involved during micturition are the detrusor muscle and the internal urethral sphincter.
- The **detrusor muscle** is a smooth muscle layer that forms the wall of the bladder.

4. **Action of the Detrusor Muscle**:
- Parasympathetic stimulation causes the detrusor muscle to **contract**. This contraction helps to push urine out of the bladder.

5. **Action of the Internal Urethral Sphincter**:
- Simultaneously, the internal urethral sphincter undergoes **relaxation**. This relaxation allows urine to flow from the bladder into the urethra.

6. **Conclusion**:
- Therefore, during micturition, the parasympathetic activity causes the **contraction of the detrusor muscle** and the **relaxation of the internal urethral sphincter**.

7. **Correct Answer**:
- The correct answer is that parasympathetic activity during micturition causes the contraction of the detrusor muscle and relaxation of the internal urethral sphincter.