Which of the following statement is incorrect with respect to the histology of alimentary canal ?

Options

A. Serosa is the outermost layer which is made up of a thin mesothelium with some connective tissue.
B. Muscular is is formed by smooth muscles usually arranged into an inner longitudinal layer and outer circular layer.
C. Submucosal layer is formed of loose connective tissue.
D. An oblique muscle layer may by present in the stomach.

Answer

To determine which statement is incorrect regarding the histology of the alimentary canal, we need to analyze the structure and layers of the alimentary canal. Here’s a step-by-step breakdown of the histology:

### Step 1: Understand the Layers of the Alimentary Canal
The wall of the alimentary canal is composed of four main layers:
1. **Serosa**: The outermost layer, made up of thin mesothelium and connective tissue.
2. **Muscularis**: This layer consists of smooth muscle. It is typically arranged with an inner circular layer and an outer longitudinal layer. In some regions of the stomach, there is an additional oblique muscle layer.
3. **Submucosa**: This layer is made of loose connective tissue and contains nerves, blood vessels, and lymphatics.
4. **Mucosa**: The innermost layer, which can vary in structure. It may have folds (rugae in the stomach) or projections (villi in the intestines).

### Step 2: Analyze the Statements
Now, let's evaluate the statements provided in the question:

1. **Statement A**: "Serosa is the outermost layer which is made up of thin mesothelium with some connective tissue."
- This statement is correct.

2. **Statement B**: "Muscularis is formed by smooth muscles, usually arranged into inner longitudinal layer and outer circular layer."
- This statement is incorrect. The muscularis is made up of smooth muscle arranged in an inner circular layer and an outer longitudinal layer, not the other way around.

3. **Statement C**: "Submucosa is formed of loose connective tissue."
- This statement is correct.

4. **Statement D**: "An oblique muscle layer may be present in the stomach."
- This statement is correct.

### Conclusion
The incorrect statement regarding the histology of the alimentary canal is **Statement B**.

### Final Answer
**B**: Muscularis is formed by smooth muscles usually arranged into inner longitudinal layer and outer circular layer. (This statement is incorrect.)

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