GI Part I Flashcards
Explain sphlanchic circulation
What is the role of each layer of the GI wall?
What are the control mechanisms of GI function?
Source of Gastrin
G Cells
(antrum-stomach,duodenum)
Source of CCK (Cholecystokinin)
I Cells
(duodenum & jejunum)
Source of Secretin “Natures Antacid”
S Cells
(duodenum & jejunum)
Source of GIP (GLIP) GLP
K Cells ; L Cells
(duodenum & jejunum)
Source of Motilin
M-Cells
(duodenum & jejunum)
Source of Somatostatin (technically a peptide)
D Cells
(pancreaticislets, GI mucosa)
Stimuli for secretion Gastrin
Peptides/AA’s
Distention of stomach
Vagal Stimulation (GRP)
Stimuli for secretion CCK
Peptides/AA’s
FFA’s
Stimuli for secretion secretin “Natures antacid”
H+ (pH<4.5)
FFA’s
Stimuli for secretion GIP (GLIP) GLP
Oral Glucose
Peptides/AA’s
FFA’s
Stimuli for secretion motilin
Neural? Decreased vagus signaling.
Stimuli for secretion Somatostatin (technically a peptide)
H+
Action of Gastrin
↑ Gastric H+ secretion
↑ Growth of gastric mucosa.
↑ Gastric motility
Action of CCK
↑ Pancreatic enzyme/HCO3-secretion (weaker than secretin)
↑ Contraction of gallbladder/relax Sphincter of Oddi
↓ Gastric emptying
↑ Trophiceffects on pancreas / gallbladder
Action of Secretin “Nature’s antacid”
↑ Pancreatic &Biliary HCO3-secretion
↓ Gastric H+ secretion
↓ Growth of gastric mucosa/↑ Trophic effects on pancreas
Action of GIP (GLIP) GLP
↑ Pancreatic insulin secretion
↓ Gastric H+ secretion
Action of Motilin
↑Migrating Motor Complex during fasting to clear excess debris from GI system and prevent SIBO
Action of Somatostatin (technically a peptide)
↓ Gastric H+ secretion
↓ Pancreatic enzyme/HCO3-secretion
↓ Gallbladdercontraction
How does the enteric nervous system (ENS) play a role in GI innervation and function?
How are the extrinsic (ANS) & intrinsic (ENS) connected?
What are the major functions?
What are the major functions?
What are the major functions?
What are the major functions?
What overall does an increase in parasympathetic activity do?
What overall does an increase in sympathetic activity do?
What are the control mechanisms of GI function?
Where is the myenteric plexus located in the GI wall, and what is it’s major role?
It is located between the longitudinal and circular muscle layers and it is mostly innervated by the enteric neurons that play a major role in motility
Where is the submucosal plexus located within the GI layers, and what is it’s major function?
It is located between the circular muscle and the muscularis mucosae (major located of blood vessels) and is mostly reflexes through the enteric nervous system (both short and long reflexes)
How does parasympathetic and sympathetic innervation differ within the GI system?
How is GI blood supply controlled?
What is Basal Electrical Rhythm (BER) or “slow waves…”?
What peptides and or hormones have the most control over arteriole blood flow?
How does the ANS control blood flow and motility/absorption?
How is GI blood supply controlled locally?
How can the GI system fight off pathogens?
How is salivation controlled?
How do we make saliva?
What are the ionic components of saliva?
“Why does flow rate affect things so much?”
What are the key cells that mediate gastric secretion?
How important is the Vagus for gastric secretions?
What role does acid secretions play in the conversion of pepsinogen to pepsin? What does pepsin do?
What triggers the parietal cells to secrete gastric acid?
What are the major regulators of the parietal cell?
Why doesn’t the stomach digest itself?
How is pancreatic secretion regulated?
Pancreatic secretion is regulated by the Vagus, CCK and Secretin!
What are pancreatic secretions composed of?
What are the actions of the pancreatic enzyme secretions?
What is the main function of the gallbladder?
Gallbladder: bile filling & storage & concentration
What is the solubility of bile composted of? What happens when the ratio is out of control?
Gallstones can form when cholesterol is too high and there is risk for blocking the Sphincter of Oddi, which can cause pancreatitis.
How does the gallbladder release bile?
Review of Enterohepatic circulation of bile…
The liver conducts a huge number of metabolic reactions and serves to detoxify and dispose of many exogenous substances, as well as metabolites endogenous to the body that would be harmful if allowed to accumulate.
Liver: Perfusion & functions
The intestine has an unusual circulation, in that the majority of its venous outflow does not return directly to the heart, but rather is directed initially to the liver via the portal vein. This integrates the many functions of the liver into the systemic physiology.
Explain the Hepatic conjugation of bilirubin
Explain the pathology of cirrhosis of the liver
