The smallest part of colon and lacking mesentry is

Options

A. Ascending
B. Descending
C. Transverse
D. Sigmoid

Answer

To answer the question, "The smallest part of the colon and lacking mesentery is," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of the Large Intestine**:
- The large intestine consists of four main parts: cecum, colon, rectum, and anus.

2. **Identify the Parts of the Colon**:
- The colon is divided into four sections: ascending colon, transverse colon, descending colon, and sigmoid colon.

3. **Determine the Length of Each Part**:
- Ascending colon: approximately 8 inches
- Descending colon: approximately 12 inches
- Sigmoid colon: approximately 18 inches
- Transverse colon: approximately 18 inches

4. **Identify the Smallest Part**:
- From the lengths provided, the ascending colon is the shortest part of the colon.

5. **Understand the Concept of Mesentery**:
- Mesentery is a fold of tissue that attaches the intestines to the abdominal wall and contains blood vessels, nerves, and lymphatics.

6. **Identify Which Parts Lack Mesentery**:
- The ascending colon and descending colon are in close contact with the body wall, causing their mesentery to fuse with the parietal peritoneum, leading to a lack of mesentery.

7. **Conclude the Answer**:
- Therefore, the smallest part of the colon that lacks mesentery is the ascending colon.

### Final Answer:
The smallest part of the colon and lacking mesentery is the **ascending colon**.