NURS 6501: MIDTERM EXAM: Please contact Assignment Samurai for help with NURS 6501: Midterm Exam or any other assignment. Email: assignmentsamurai@gmail.com   A patient with chronic gastritis develops vitamin B12 deficiency. Which of the following best explains this association? Group of answer choices

• Gastritis causes decreased absorption of vitamin B12 in the duodenum
• Gastritis increases secretion of hydrochloric acid, which destroys vitamin B12
• Gastritis causes direct malabsorption of all vitamins
• Gastritis leads to loss of parietal cells, reducing intrinsic factor production necessary for vitamin B12 absorption

  The correct answer is Gastritis leads to loss of parietal cells, reducing intrinsic factor production necessary for vitamin B12 absorption.   Explanation: Chronic gastritis, particularly autoimmune gastritis, can lead to the destruction of parietal cells in the stomach lining. Parietal cells are responsible for producing intrinsic factor, a glycoprotein that is essential for the absorption of vitamin B12 in the ileum. Without intrinsic factor, vitamin B12 cannot bind properly and cannot be absorbed, leading to vitamin B12 deficiency. Why the other options are incorrect:

• Gastritis causes decreased absorption of vitamin B12 in the duodenum: Vitamin B12 is not absorbed in the duodenum; it is absorbed in the ileum, and its absorption depends on intrinsic factor, not duodenal processes.
• Gastritis increases secretion of hydrochloric acid, which destroys vitamin B12: In fact, gastritis is more often associated with decreased acid secretion (particularly in atrophic gastritis), not increased secretion. Acid is not directly involved in destroying vitamin B12.
• Gastritis causes direct malabsorption of all vitamins: Gastritis does not typically cause a generalized malabsorption of all vitamins. The main issue in chronic gastritis related to vitamin B12 is the loss of intrinsic factor, not a broad malabsorption syndrome.

Thus, the correct explanation for vitamin B12 deficiency in chronic gastritis is the loss of parietal cells, leading to reduced production of intrinsic factor necessary for B12 absorption