GASTRIC SECRETION

Question 1

TYPE OF CELLS ON GASTRIC ACID & FUNCTION

Answer 1

1. PARIETAL CELL
   -secrete HCl & intrinsic factor
2. PEPTIC CELL
   
   • Secrete pepsin
3. G CELL
   
   • secrete gastrin
4. MUCUS CELL
   
   • Secrete mucuc bicarbonate HCO3-

Question 2

FUNCTION OF STOMACH

Answer 2

1. Storage organ (meal)
2. Digest protien (pepsin)
3. HCO3- & Mucus (epithelium protection)
4. Converts Fe 3+ to Fe2+ (by HCl)
5. Produce hormones
   - GASTRIN (stimulate gastric secretion)
   - SOMASTATIN (inhibit GIT secretion)
   - HISTAMINE (stimulate HCL secrete)

Question 3

REGULATION OF GASTRIC SECRETION

Answer 3

1. CEPHALIC (before food reaches the stomach)
   stimuli
   - taste // smell // chewing
   mechanism
   - Direct stimulate parietal cells
   - Indirect stimulation of gastrin release
2. GASTRIC (bolus reaches stomach)
   stimuli
   -Distension of stomach
   -Amino acids & peptides
   mechanism
   -Vagovagal reflex
   -Local reflex (excite Meissener’s plexus)
   -Hormonal Reflex
   *Stimulate G cell - gastric secretion
   *Effect on parietal cells & secretion of histamine (Histamine increase HCl secretion)
3. INTESTINAL (chyme in intestine)
   stimulate
   -Ach // Gastrin // Histamine

Question 4

MUCOSAL BARRIER

Answer 4

1. PEPTIC ULCER
   causes
   - loss of protective mucosal barrier (mucus, HCO3-, Prostaglandin & mucosal blood flow)
   - excessive H+ & pepsin
   treatment
   -omeprazole (Block H2)
   -Ranitidine // Fomatidine (block H2)