Intrinsic factor is produced by which cells within the stomach?

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Explanation

Parietal cells, also called oxyntic cells, are located in the gastric glands found in the fundus and body of the stomach.
These cells are responsible for secreting two key substances: hydrochloric acid (HCl) and intrinsic factor.
Intrinsic factor is a glycoprotein essential for the absorption of vitamin B12 in the terminal ileum.
The secretion of intrinsic factor is the key differentiator that makes this option correct.

Option A: Mucous cells (or surface epithelial cells) secrete a protective layer of alkaline mucus. This mucus shields the stomach lining from the corrosive effects of hydrochloric acid and digestive enzymes.
Option B: Chief cells (or peptic/zymogen cells) are responsible for secreting pepsinogen. Pepsinogen is an inactive proenzyme that is converted to the active enzyme pepsin by stomach acid. Pepsin begins the digestion of proteins.
Option C: Enteroendocrine cells are hormone-secreting cells. A key example is the G cell, which secretes the hormone gastrin. Gastrin stimulates the parietal cells to secrete more hydrochloric acid.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of Gastric Secretions as background academic context rather than a clinical decision trigger.
Understanding the function of parietal cells is critical for recognizing the cause of pernicious anemia. A lack of intrinsic factor leads to vitamin B12 deficiency, causing this specific type of anemia.
Nurses must educate patients who have undergone gastrectomy or gastric bypass surgery about the need for lifelong vitamin B12 supplementation (usually via injections), as their bodies can no longer produce intrinsic factor.
What if? If a patient presents with symptoms of anemia (fatigue, weakness, pale skin) and has a history of autoimmune gastritis, the nurse should anticipate that the underlying cause could be pernicious anemia due to the destruction of parietal cells.

How to Approach the Question

First, identify the core concept of the question, which is the origin of 'intrinsic factor' in the stomach.
This is a factual recall question based on anatomy and physiology.
Mentally review the different cell types found in the gastric glands and their primary secretions.
Match 'intrinsic factor' to its producing cell: Parietal cells secrete both HCl and intrinsic factor.
Evaluate the other options to confirm they are incorrect: Chief cells (pepsinogen), Mucous cells (mucus), and Enteroendocrine cells (hormones).
Select the option that correctly identifies the source of intrinsic factor.

Concept Tested & Keywords

QGBnZNZr-njpF-C99UllOG

E6 Histology Inderbir 11e p. 38-40

E6 Pharmacology Nursing Lilley 11e Part 3 p. 162-164

Practise the full RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Attempt every question from this paper in a timed mock, then review the full solution for each one.