Vitamin B12 and bile salts are decreases in the resection of
**Core Concept**
Vitamin B12 and bile salts are absorbed in the terminal ileum, which is the last part of the small intestine. This process is crucial for the absorption of these essential nutrients. The ileum's unique function is compromised in certain surgical procedures.
**Why the Correct Answer is Right**
The correct answer is related to the surgical resection of the ileum. The terminal ileum is responsible for the absorption of vitamin B12 and bile salts due to the presence of specific receptors and enzymes. Vitamin B12 is absorbed through a complex process involving intrinsic factor, a protein produced by the stomach, and the ileal receptor. Bile salts, on the other hand, are reabsorbed in the terminal ileum through a sodium-dependent transport mechanism. Resection of the ileum disrupts these processes, leading to malabsorption of vitamin B12 and bile salts.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the absorption of vitamin B12 and bile salts. The stomach is primarily responsible for the digestion of food, not the absorption of these nutrients.
**Option B:** The duodenum is the first part of the small intestine and is primarily responsible for the absorption of nutrients such as iron, calcium, and vitamin D. It is not involved in the absorption of vitamin B12 and bile salts.
**Option C:** The jejunum is the middle part of the small intestine and is responsible for the absorption of carbohydrates, proteins, and fats. While it plays a crucial role in nutrient absorption, it is not involved in the absorption of vitamin B12 and bile salts.
**Clinical Pearl / High-Yield Fact**
In patients undergoing ileal resection, vitamin B12 deficiency can lead to megaloblastic anemia, and bile salt malabsorption can cause diarrhea and steatorrhea. These complications can be prevented or managed with appropriate supplementation and dietary modifications.
**Correct Answer: D. Ileum**