Skip to main content
Ch. 19 Blood
Martini - Fundamentals of Anatomy & Physiology 11th Edition
Martini, Nath, Bartholomew11th EditionFundamentals of Anatomy & PhysiologyISBN: 9780136874089Non è quello che usi tu?Cambia libro di testo
Capitolo 19, Problema 31

After Randy was diagnosed with stomach cancer, nearly all of his stomach had to be removed. Postoperative treatment included regular injections of vitamin B12. Why was this vitamin prescribed, and why were injections specified?

Guida verificata passo dopo passo
1
Understand the role of vitamin B12 in the body: Vitamin B12 is essential for red blood cell formation, neurological function, and DNA synthesis.
Recognize that vitamin B12 absorption requires intrinsic factor, a protein secreted by parietal cells in the stomach lining, which binds to vitamin B12 and allows its absorption in the ileum.
Since Randy had nearly all of his stomach removed, the intrinsic factor production is severely reduced or absent, impairing the normal absorption of vitamin B12 from the diet.
Because oral vitamin B12 cannot be effectively absorbed without intrinsic factor, vitamin B12 injections are prescribed to bypass the gastrointestinal tract and deliver the vitamin directly into the bloodstream.
Therefore, the injections ensure that Randy receives adequate vitamin B12 to prevent deficiency-related complications such as pernicious anemia and neurological problems.

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Role of Vitamin B12 in the Body

Vitamin B12 is essential for red blood cell formation, DNA synthesis, and neurological function. It is primarily absorbed in the ileum after binding to intrinsic factor, a protein produced by stomach cells. Deficiency can lead to anemia and neurological issues.
Video consigliato:

Intrinsic Factor and Vitamin B12 Absorption

Intrinsic factor is a glycoprotein secreted by parietal cells in the stomach lining, necessary for vitamin B12 absorption in the small intestine. Removal of most of the stomach reduces intrinsic factor production, impairing B12 absorption and causing deficiency.

Rationale for Vitamin B12 Injections Post-Gastrectomy

After stomach removal, oral vitamin B12 cannot be absorbed effectively due to lack of intrinsic factor. Therefore, vitamin B12 is administered via injections to bypass the gastrointestinal tract, ensuring adequate levels and preventing deficiency-related complications.
Video consigliato:
Percorso guidato
04:26
Post-Translational Modification