Physio of the GI system

Question 1

Gastrin

Answer 1

Endocrine

secreted in Gastric antrum (distal stomach) by G cells

stimuli for secrtion are small peptides and amino acids

stimulates parietal cells to release H+

stimulates ECL cells to secrete histamine

stimulates growth of gastric mucosa

Question 2

CCK

Answer 2

Paracrine (acts locally on nerve cells) and Endocrine (acts on pancreas)

secreted from I cells of duodenum

stimuli for secretion are fatty acids and hydrolyzed protein

decreases gastric emptying and H+ secretion

decreases food intake

increases pacreatic enzyme secretoin

increases contraction of gall bladder

Question 3

Secretin

Answer 3

Paracrine and Endocrine

S cells of the duodenum

stimuli for secretion is H+ in the duodenum

causes increased pancreatic ductal secretion (H2O and HCO3)

Question 4

GIP (glucoinsulinotrpoic peptide)

Answer 4

Endocrine

K cells of duodenum and jejunum

stimuli of secretion is fatty acids, glucose,

increaes insulin secretion from pancreas (beta cells)

Question 5

Peptide YY

Answer 5

Paracrine and endocrine

L cells in the intestine

stimulation for secretion is fatty acids, glucose, hydrolyzed protein

decreases gastric emptying

decreases pancreatic secreiton

decreases intestinal mobility

**decreases food intake **

Question 6

Proglucagon derived peptides 1/2 (GLP - 1/2)

Answer 6

Paracrine and Endocrine

secreted by L cells of the intestine

stimulation for secretion is fatty acids, glucose, and hydrolyzed protein

promotes glucose homeostasis

increased epithelial cell proliferation

Question 7

enterochromaffin like cells (ECL)

Answer 7

release histamine

Question 8

Serotonin

Answer 8

releaed from enteric neurons, mucosal mast cells, and specialized EECs called enterochromaffin cells.

they regulate the contractility of SM cells in the GI system

Question 9

Celiac disease

Answer 9

allergic response to gliadin

imflammatory reaction in small intestines

reduction in length and density of the microvilli, causes reduced absorption of nutrients

Question 10

Vagal nerve innervates

Answer 10

esophagus

stomach

gallbladder

pancreas

1st part of intestine

cecum

proximal part of colon

Question 11

Parasympathetic pelvic nerves innervate

Answer 11

distal part of colon

anorectal region

Question 12

Which nerves control salivary secretion

Answer 12

facial nerve VII

Glossopharyngeal nerve IX