GI general

Question 1

Describe the secretory products and function of Parietal cell

Answer 1

• Parietal cells secrete HYDROCHOLORIC ACID (HCl)

–> function is protein digestion,s terilization, nutrient absorption

Question 2

describe the secretory product and function of superifical epithelial cells

Answer 2

• superficial spithelial cells secrete MUCUS and BICARBONATE

–> function in gastroprotection

• prostaglandins + acetylcholine PROMOTE secretion of mucus and bicarbonate from gastric epithelial cells

Question 3

describe the secretory product and function of ECL cells

Answer 3

• ECL cells secrete histamine

–> function is to promote HCl secretion

• HISTAMINE is a PARACRINE REGULATOR

Question 4

describe the secretory product and function of G cells

Answer 4

• G cells secrete GASTRIN

–> function is the promote HCl secretion

• Gastrin acts as an endocrine regulator both directly and indirectly

–> directly stimulates parietal cell to increase activity of H+/K+-ATPase

–> Indirectly by inducing histamine release from ECL cells

Question 5

describe the inhibition of gastric acid secretion

Answer 5

• Paracrine release of Prostaglandins (PGE2)

–> DECREASES/NEGATIVELY regulates H/K-ATPase activity

• SOMATOSTATIN released by Gastric D cells DECREASES acid secretion by inhbits:

–> release of gastrin from G cells

–> release of histamine from ECL cells

–> inhibits H/K-ATPase

Question 6

describe the role of prostaglandins

Answer 6

• mucus and bicarbonate secretion
• suppression of HCl secretion
• increased gastric blood flow

Question 7

what are the effects of disrupting acid secretion?

Answer 7

• Peptic ulcers = break in protective mucosal lining
• duodenal ulcers
• gastric ulcers
• stress ulcer
• cushing ulcer
• ischemic ulcers

Question 8

describe the symptoms of ulcers

Answer 8

• abdominal pain
• nausea
• vomiting, vomiting blood
• bloody or tarry stool
• indigestion
• weight loss
• fatigue