Gastrointestinal physiology and pharmacology

Question 1

What occurs when parietal cells become activated?

Answer 1

• increase in number of transporters on apical membrane

Question 2

What are the three molecules and their receptors which result in the activation of these parietal cells?

Answer 2

• Histamine - H2
• Acetylcholine - M3
• Gastrin - CCKB

Question 3

What are the mechanisms of drugs which reduce amount of acid secretion?

Answer 3

• H+/K+ ATPase inhibitors
• H2 receptor inhibitors
• Drugs that neutralize acids

Question 4

3 parts of the small intestine

Answer 4

• duodenum - most digestion occurs here (enzymes mixing with chyme)
• jejunum - many villi to increase SA (most absorption occurs here)
• ileum - can still absorb nutrients if necessary

Question 5

2 types of motility in small intestine

Answer 5

• segmentation - specialized local contractions to increase interactions between chyme and cells of mucosa layer
• peristalsis

Question 6

What re the different brush border enzymes located on microvilli?

Answer 6

Lactase - lactose into glucose + galactose

Sucrase - sucrose into glucose + fructose

Maltase - maltose into glucose + glucose

• Aminopeptidase
• Dipeptidase
• Enteropeptidase/Enterokinase