The wall of urinary bladder has a thick layer of smooth muscle called

Options

A. Dartos
B. Detrusor
C. Deltoid
D. Depressor

Answer

To answer the question, "The wall of the urinary bladder has a thick layer of smooth muscle called," we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Structure of the Urinary Bladder**:
- The urinary bladder is a muscular sac that stores urine. Its wall is composed of several layers, including an inner lining and a muscular layer.

2. **Focus on the Muscular Layer**:
- The muscular layer of the urinary bladder is crucial for its function, particularly in the process of urination.

3. **Name the Specific Muscle Layer**:
- The thick layer of smooth muscle in the wall of the urinary bladder is known as the **detrusor muscle**.

4. **Understand the Function of the Detrusor Muscle**:
- The detrusor muscle is responsible for contracting during urination (micturition), which helps to expel urine from the bladder.

5. **Eliminate Incorrect Options**:
- The other options provided (Dartos, Deltoid, and Depressor) refer to different muscles:
- **Dartos** is found in the scrotum.
- **Deltoid** is located in the shoulder.
- **Depressor** refers to facial muscles.
- Therefore, these options do not pertain to the urinary bladder.

6. **Conclude with the Correct Answer**:
- Based on the information, the correct answer to the question is **detrusor muscle**.

### Final Answer:
The wall of the urinary bladder has a thick layer of smooth muscle called the **detrusor muscle**.