Select the correct structural sequence of alimentary canal facing from inside to outside.

Options

A. Serosa `rarr` Muscularis `rarr` Submucosa `rarr` Mucosa
B. Muscularis `rarr` Serosa ` rarr` Mucosa `rarr` Submucosa
C. Mucosa `rarr` Submucosa`rarr` Muscularis ` rarr ` Serosa
D. Submucosa ` rarr` Mucosa `rarr` Muscularis `rarr` Serosa

Answer

To determine the correct structural sequence of the alimentary canal from the inside to the outside, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Innermost Layer**:
- The innermost layer of the alimentary canal is the **lumen**, which is the hollow space where food passes through.

2. **Mucosa Layer**:
- Lining the lumen is the **mucosa**. This layer is responsible for secretion and absorption.

3. **Submucosa Layer**:
- Below the mucosa is the **submucosa**. This layer contains blood vessels, nerves, and connective tissue.

4. **Muscularis Layer**:
- Following the submucosa is the **muscularis** layer. This layer consists of two main types of muscle:
- **Inner Circular Layer**: Helps in constricting the lumen.
- **Outer Longitudinal Layer**: Helps in shortening the length of the canal.
- In the stomach, there may also be an **oblique layer** present, which aids in churning movements.

5. **Outer Layer (Cirrhosa)**:
- The outermost layer is the **serosa**, also known as the **visceral peritoneum** or **mesothelium**. This layer provides a smooth surface for the organs and helps reduce friction.

### Final Sequence:
Putting it all together, the correct structural sequence of the alimentary canal from inside to outside is:
1. Lumen
2. Mucosa
3. Submucosa
4. Muscularis (with inner circular and outer longitudinal layers, and possibly an oblique layer in the stomach)
5. Serosa (visceral peritoneum)