Pack Flashcards
What are the classic/offical hormones produced by the enteroendocrine APUD cells?
Secretin, gastrin, CCK, GIP
What are the neurocrines produced ENS neurons?
VIP, GRP, enkephalins
What are the paracrines produced in the GIT by ENS?
Somatostatin, histamine
What are the sites where gastrin is produced?
Antrum (Most), duo,
What are the sites where CCK is produced?
Duo
What are the sites where Secretin is produced?
Duo, jejun, illeum
What are the sites where GIP is produced?
duo and jejun
What are the sites where motilin is produced?
Duo, Jejnum
What is the concentration of serum gastrin that indicates that a person has a Zollinger-Ellison Syndrome (Gastrinoma) after ChiRhoStim is adminstered?
Above 110 pg/ml
What is gastrin stimulated by?
Secretion is stimulated by protein digestion products
— Nervous impulses, physical distention
— calcium, regular &decaf coffee, and wine
What is gastrin inhibted by?
Secretion is inhibited by acidification of antrum
What does gastrin stimulate?
Gastrin stimulates pyloric contraction and increases cardiac sphincter tone, preventing
reflux. Gastrin also stimulates acid and pepsinogen secretion and antral motility, thus
facilitating gastric digestion
How does gastrin effect the mucosa?
Stimulates growth of oxyntic mucosa of the stomach, the duodenal mucosa, and colonmucosa
Surgical removal ofthe antrum causes atrophy.
What do patients with gastrinomas have in relation to the mucosa?
Patients with gastrin-secreting tumors have mucosal hyperplasia and hypertrophy.
What does CCK do in relation to sphinchers and enzymes?
Contraction of pyloric
sphincter and inhibition
of gastric emptying
↑ pancreatic
secretion of enzymes
↑ glucagon secretion
Augments the secretin effect
on secretion of bicarbonate
in the pancreas and liver
What kinase does CCK increase the secretion of?
Enterokinase
In what conditions does cck have maximal effect?
Normal vagal tone and the prescence of secretin
What does CCK do in relation to the gall bladder?
Gallbladder contraction, emptying
of the gallbladder and relaxation of
the sphincter of Oddi
What does secretin do in realtion with the spintchers and secretion?
May stimulate the contraction of the pyloric spintcher
Inhibts the secretion of HCL and gastric motility
What does secretin do in relation with CCK
Augments its action on the pancreas and antagonises gastrin
What does secretin do in relation with bicarbonate?
Stimulates its secretion from the pancreatic duct cells and biliary tract
What stimulates secretin secretion?
Stimuli for release
- Acid in duodenum and jejunum (pH <4.5)
(small amounts can be released fromileum)
- Fatty acids
What does secritin do in relation to pepsin?
Stimulates pepsin secretion
Where is GIP released from and what stimulates its release?
- Released from K-cells of duodenum and proximal jejunum
- All major foodstuffs—fat must be hydrolyzed.
- Oral glucose but not i.v. glucose
What does GIP stimulate the release of and what does it inhibit?
Stimulates the release of insulin and inhibits gastrin (Enterogasrone)
What are PROGLUCAGON-DERIVED PEPTIDES (GLPGLUCAGON-LIKE PEPTIDES) released from and what stimulates their release?
L cells
oral ingestion of Carbohydrates or fats
What do PROGLUCAGON-DERIVED PEPTIDES (GLPGLUCAGON-LIKE PEPTIDES) do in relation to insulin and glucagon?
Secretion, thus called an incretin hormone
- Suppresses glucagon secretion
What do PROGLUCAGON-DERIVED PEPTIDES (GLP GLUCAGON-LIKE PEPTIDES) do in relation to gastric emptying, food aptite, and beta cell profilation?
Slows gastric emptying
- Reducesfood intake via the reduction of appetite
- Promotes beta cell proliferation.
How does GLP help pateints with Type 2 diabetes?
In patients with type 2 diabetes mellitus (T2DM), GLP-1 concentrations are
decreased in response to an oral glucose load. Clinical data have demonstrated
that GLP-1 receptor agonists therapies help restore insulin secretory functions, thus improving glycemic control and reducing body weight in patients with T2DM
What is the structure of molitin?
Linear 22 AA polypeptide - unrelated to other hormones
What is molitin released from and what stimualtes its release?
Released from M cells
Fasting stimulates it and it is released in 100 min intervals
- Release is under neural control (acid and fat can also
- cause small amounts to be released)
What does motilin to in relation to motility?
Stimulates upper GI motility
Accounts for the migrating motility complexes
Where is somatostatin found and what stimulates its release?
Found in gastric/duodenal mucosa and pancreas
- Release—stimulated by acid, inhibited by Ach
What does somatostatin inhibit?
Inhibits release of all gut hormones
- Directly inhibits parietal cell acid secretion
- Mediates acid-induced inhibition of gastrin release
What stimulates the release of histamine?
Gastrin and Ach cause release from cellsin the stomach
What does histamine stimulate?
The release of gastric acid
What are examples of histamine (H2) receptor blockers and what do they do?
- Cimetidine (Tagamet), Ranitidine (Zantac)
Decrease the release of acid
What is the location of the neurocrines: VIP, GRP, Enkephalins?
