The wall of alimentary canal from oesophagus to rectum posses four layers. The sequence of these layers is -

Options

A. Serosa - Mucosa -Submucosa - Muscularis
B. Muscularis - Serosa -Mucosa -Submucosa
C. Serosa -Muscularis -Mucosa -Submucosa
D. Serosa- Muscularis -Submucosa- Mucosa

Answer

To answer the question regarding the sequence of the four layers of the wall of the alimentary canal from the esophagus to the rectum, we can break it down step by step:

### Step-by-Step Solution:

1. **Identify the Layers**: The wall of the alimentary canal consists of four distinct layers. These layers are arranged from the outermost to the innermost.

2. **Outermost Layer - Serosa**: The first layer, which is the outermost, is called the **serosa**. This layer serves as a protective outer covering of the alimentary canal.

3. **Second Layer - Muscularis**: Beneath the serosa is the **muscularis** layer. This layer is responsible for the movement of the alimentary canal and is further divided into two parts:
- **Inner Muscularis**: Arranged in a circular manner.
- **Outer Muscularis**: Arranged in a longitudinal manner.

4. **Third Layer - Submucosa**: The next layer is the **submucosa**. This layer contains blood vessels, nerves, and glands that support the functions of the alimentary canal.

5. **Innermost Layer - Mucosa**: The innermost layer is called the **mucosa**. This layer is involved in the secretion of digestive enzymes and absorption of nutrients.

6. **Sequence of Layers**: Therefore, the correct sequence of the layers from outermost to innermost is:
- **Serosa**
- **Muscularis**
- **Submucosa**
- **Mucosa**

### Final Answer:
The sequence of the layers of the wall of the alimentary canal from the esophagus to the rectum is: **Serosa, Muscularis, Submucosa, Mucosa**.