Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

23. The Digestive System

The Stomach

Anatomy & Physiology

23. The Digestive System

The Stomach

Previous problemNext problem

Problem L3.2b

Textbook Question

A surgical procedure known as gastric bypass involves creating a small upper stomach pouch and attaching part of the small intestine to this pouch, “bypassing” the rest of the stomach and part of the duodenum.
How would bypassing a significant portion of the stomach affect absorption of vitamin B12? Explain.

Verified step by step guidance

Understand the role of the stomach in vitamin B12 absorption: The stomach produces intrinsic factor, a glycoprotein essential for the absorption of vitamin B12 in the small intestine. Without intrinsic factor, vitamin B12 cannot be absorbed effectively.

Recognize the impact of gastric bypass surgery: By creating a small stomach pouch and bypassing the majority of the stomach, the production of intrinsic factor may be significantly reduced, as the cells responsible for its secretion (parietal cells) are located in the bypassed portion of the stomach.

Consider the role of the duodenum: The duodenum is the initial segment of the small intestine where intrinsic factor binds to vitamin B12. Bypassing the duodenum may further disrupt the absorption process, as this binding step is critical for vitamin B12 uptake in the ileum.

Evaluate the consequences of reduced vitamin B12 absorption: A lack of intrinsic factor and bypassing the duodenum can lead to vitamin B12 deficiency, which may result in anemia (specifically pernicious anemia), neurological issues, and other health complications.

Discuss potential solutions: Patients who undergo gastric bypass surgery may require vitamin B12 supplementation, either through oral high-dose supplements, sublingual tablets, or intramuscular injections, to compensate for the reduced absorption capacity.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Gastric Bypass Procedure

Gastric bypass is a weight-loss surgery that alters the digestive system by creating a small pouch from the stomach and connecting it directly to the small intestine. This procedure limits food intake and alters nutrient absorption, which can lead to various nutritional deficiencies, including vitamin B12.

Vitamin B12 Absorption

Vitamin B12 absorption primarily occurs in the ileum, the last part of the small intestine, and requires intrinsic factor, a protein produced in the stomach. Bypassing a significant portion of the stomach can reduce intrinsic factor production, leading to impaired absorption of vitamin B12 and potential deficiency.

Nutritional Deficiencies Post-Surgery

Post-surgical patients, especially those who undergo gastric bypass, are at risk for nutritional deficiencies due to altered digestion and absorption. Regular monitoring and supplementation of vitamins and minerals, particularly vitamin B12, are essential to prevent complications such as anemia and neurological issues.

Watch next

Master Gross Anatomy of the Stomach with a bite sized video explanation from Bruce Bryan

Start learning

Related Videos

Related Practice

Multiple Choice

In which direction do the peristaltic contractions of the stomach's smooth muscle move contents?

views

Multiple Choice

What protects the lining of the stomach from acidic gastric juices?

171

views

Multiple Choice

Which part of the gastrointestinal tract contains highly acidic digestive juices?

118

views

Textbook Question

A surgical procedure known as gastric bypass involves creating a small upper stomach pouch and attaching part of the small intestine to this pouch, “bypassing” the rest of the stomach and part of the duodenum.

Ms. Anthony has undergone gastric bypass. She goes out to dinner and eats an extremely large meal. Explain what will happen in her small and large intestines following this meal.

views