In which part of the alimentary canal the negligible amount of absorption of substance take place?

Options

A. mouth
B. Stomach
C. Small intestine
D. oesophagus

Answer

To determine the part of the alimentary canal where negligible absorption of substances takes place, we can analyze each section of the canal:

1. **Mouth**: The mouth is involved in the initial stages of digestion. While it primarily functions in mechanical digestion and the mixing of food with saliva, certain substances, particularly some drugs, can be absorbed through the mucosa of the mouth and under the tongue. However, this absorption is limited.

2. **Stomach**: The stomach is responsible for the digestion of food through gastric juices. While it does absorb some substances such as water, simple sugars, and alcohol, the overall absorption is still not as extensive as in other parts of the alimentary canal.

3. **Small Intestine**: The small intestine is the principal organ for absorption. It has a large surface area due to villi and microvilli, allowing for the absorption of nutrients like glucose, fatty acids, and amino acids. This is where the majority of nutrient absorption occurs.

4. **Esophagus**: The esophagus serves primarily as a conduit for food to travel from the mouth to the stomach. It consists of four layers: mucosa, submucosa, muscularis, and serosa. The function of the esophagus is mainly to transport food, and it does not have a significant role in absorption. Therefore, the absorption of substances in the esophagus is negligible.

Based on this analysis, the part of the alimentary canal where negligible absorption of substances takes place is the **esophagus**.

**Final Answer**: Esophagus

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