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75 Cards in this Set
- Front
- Back
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Where is gastrin made?
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G cells in antrum of stomach
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Where is CCK made?
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I cells in duodenum, jejunum
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Where is secretin made?
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S cells in duodenum
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Where is somatostatin made?
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D cells in pancreatic islets, GI mucosa
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Where is GIP made?
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K cells in duodenum, jejunum
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Where is VIP made?
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parasympathetic ganglia in sphincters, gallbladder, small intestine
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Where is motilin made?
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small intestine
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Where is ghrelin made?
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P/D1 cells in stomach
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Where is intrinsic factor made?
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parietal cells in stomach
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Where is gastric acid made?
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parietal cells in stomach
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Where is pepsin made?
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chief cells in stomach
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Where is HCO3- made?
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- mucosal cells in stomach, duodenum, salivary glands, pancreas
- Brunner's glands in duodenum |
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Increases gastric H+ secretion
Increases growth of gastric mucosa Increases gastric motility |
gastrin
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increases pancreatic secretion
increases gallbladder contraction decreases gastric emptying |
CCK
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increases pancreatic HCO3- secretion
decreases gastric H+ secretion increases bile secretion |
secretin
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decreases gastric acid and pepsinogen secretion
decreases pancreatic and small intestine fluid secretion decreases gallbladder contraction decreases insulin and glucagon release |
somatostatin
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decreases gastric H+ secretion
increases insulin release |
GIP (glucose-dependent insulinotropic peptide)
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increases intestinal water and electrolyte secretion
increases relaxation of intestinal smooth muscle and sphincters |
VIP
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increases smooth muscle relaxation, including LES
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nitric oxide
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produces migrating motor complexes (MMCs)
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motilin
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Increases GH, ACTH, cortisol, and prolactin secretion
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ghrelin
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Binds vitamin B12 (required for B12 uptake in terminal ileum)
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intrinsic factor
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decreases stomach pH
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gastric acid
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protein digestion
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pepsin
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neutralizes acid
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HCO3-
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What effects does vagal stimulation have on GI hormonal secretions?
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Vagal stimulation increases gastrin, pepsin, and VIP
Vagal stimulation decreases somatostatin |
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Increased in Zollinger-Ellison syndrome
Phe and Trp are potent stimulators |
Gastrin
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Produces colicky pain in colelithiasis
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CCK
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neutralizes gastric acid in duodenum, allowing pancreatic enzymes to function
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secretin/HCO3-
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Antigrowth hormone effects
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somatostatin
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Used to treat VIPomas and carcinoid tumors
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somatostatin
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The reason why an oral glucose load is used more rapidly than IV load
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GIP (responds to oral glucose only)
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non-a, non-B islet cell pancreatic tumor causing copious diarrhea
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VIPoma
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causes achalasia
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decreased NO secretion --> increased LES tone
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regulates hunger, meal initiation; lost following gastric bypass surgery
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ghrelin
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associated with hyperphagia in Prader-Willi
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ghrelin
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causes chronic gastritis and pernicious anemia
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loss of parietal cells/intrinsic factor
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tumor that causes continuous high levels of acid secretion and peptic ulcers
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gastrinoma
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What converts pepsinogen to pepsin?
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H+
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Where are parietal and chief cells located?
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In the body of the stomach
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Where are G cells and mucous cells located?
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In the antrum of the stomach
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What is the primary means by which gastrin increases acid release?
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G cells --> gastrin --> ECL cells --> histamine --> H2 receptors (Gs)
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Which salivary gland produces the most serous secretion?
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Parotid (serous on the sides)
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Which salivary gland produces the most mucinous secretion?
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Sublingual (mucinous in the middle)
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How does flow rate affect composition of saliva?
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High flow rate - more hypotonic (reabsorbs more Na and Cl)
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What enzyme begins starch digestion in saliva?
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a-amylase (ptyalin); inactivated by low pH of stomach
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What component of saliva neutralizes oral bacterial products?
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bicarb (bacterial acids) --> dental health
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What component of saliva lubricates food?
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mucins (glycoproteins)
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What structure runs through the parotid gland but does not innervated it?
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CN VII (innervates submandibular and sublingual glands)
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Which receptor acts via increasing cAMP to increase the action of the H+/K+ ATPase?
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H2 receptor
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Which compounds act via a Gi (decreasing cAMP) to decrease the action of the H+/K+ ATPase?
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Somatostatin and prostaglandins
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Which receptors act via increasing IP3/Ca to increase the action of the H+/K+ ATPase?
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gastrin receptor
M3 receptor |
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What are the only submucosal glands in the GI tract?
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Brunner's glands; hypertrophied in PUD
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What pancreatic enzyme(s) aid in carbohydrate digestion?
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a-amylase (starch)
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What pancreatic enzyme(s) aid in fat digestion?
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lipase, phospholipase A, colipase
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What pancreatic enzyme(s) aid in protein digestion?
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trypsin
chymotrypsin elastase carboxypeptidase All are secreted as zymogens |
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Which pancreatic protease increases its own and others' secretion through positive feedback?
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trypsinogen --> trypsin
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hydrolyzes a-1,4 linkages to yield disaccharides
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salivary amylase
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hydrolyzes starch to yield oligosaccharides and disaccharides
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pancreatic amylase
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Where does the rate-limiting step of carbohydrate digestion take place?
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At the intestinal brush border
(oligosaccharide hydrolases convert oligo/disaccharides --> monosaccharides) |
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What enterocyte transporter takes up glucose?
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SGLT1 (Na+ dependent)
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What enterocyte transporter takes up galactose?
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SGLT1 (Na+ dependent)
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What enterocyte transporter takes up fructose?
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GLUT-5
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What enterocyte transporter moves ALL monosaccharides to the blood?
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GLUT-2
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What vitamin/mineral is absorbed in the duodenum?
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Iron (as Fe 2+)
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What vitamins/minerals are absorbed in the terminal ileum?
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B12
bile acids |
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What vitamin/mineral is absorbed in the jejunum?
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folate
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Where are Peyer's patches found?
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lamina propria and submucosa of ileum
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What are the components of a Peyer's patch?
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unencapsulated
M cells - take up antigen germinal centers - naive B cells are stimulated --> IgA plasma cells |
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Where do secretory IgA-secreting plasma cells ultimately reside?
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lamina propria of mucosal layer
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What are the components of bile?
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1. bile salts (bile acids conjugated to glycine to taurine)
2. cholesterol 3. water 4. ions 5. phospholipids 6. bilirubin |
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With what other substance is glucose transported from the intestinal lumen into enterocytes?
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Na+:
3Na+/2K+ ATP-driven antiporter pumps Na out on basal side --> generates concentration gradient that Na moves down --> glucose comes with |
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In what form and percentage is bilirubin:
- excreted in feces - recycled to enterohepatic circulation - excreted in urine |
- feces: stercobilin (80%)
- recycled: urobilinogen (18%) - urine: urobilin (2%) |
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Where/how is bilirubin conjugated?
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In the liver with uridine/glucuronyl transferase
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To what is unconjugated bilirubin bound in the bloodstream?
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albumin
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