GIT Flashcards
What is the PH of the stomach?
1-3 (acidic)
What are the secretions of the parietal cells/oxyntic cells?
And what influence it’s secretion?
HCL & Intrinsic factor + Mg+Na+Ca
Increases HCL:
1-H2:Histamine
2-M3:Muscarinic by vagal(Ach)
3-G:Gastrin
Decrease HCL:
1-PGE2
What are the secretions of the gastrin cells?
Present in the gastric antrum and pancreas and stimulates the HCL secretion by the parietal cells and has trophic effect on them.
What are the secretions of the Peptic (chief) cells?
Pepsinogen (activities by HCL and cause endopeptidase)
What are the secrets ions of the mucous cells?
Mucous+HCO3 (to prevent auto digestion and neutralize acidity)
Damage of parietal cells causes which types of anemia?
Pernicious anemia (due to Vit.B12 deficiency due to decrease of intrinsic factor secretion)
Iron deficiency anemia due to decreased HCL secretion
What is the clinical picture of gastrinoma?
-Recurrent peptic ulcer (⬆️HCL)
-Diarrhea and steatorhia (⬇️Lipase)
It might be part of MEN type 1
What is H-Pylori?
A gram negative organism
Increases the acid production and produces powerful urease that form the basis for Clo test
What is the action of PPIs (proton pump inhibitors)?
It inhibits the H-K ATPase pump so it is used in peptic ulcer treatment
(Primary active transport pump)
What are the drugs that affect the gastric emptying?
Metoclopramide (depend on vagus)
Erythromycin (in vagotomy)
What happens in the post gastrectomy syndrome?
Deficiency:
-Vitamin B12 deficiency: due to lack of intrinsic factors
-Iron deficiency: due to decreased acidity
Damping:
Early: (30-45mins) hyperpsmolar food
Late: insulin release
What is the pancreatic exocrine function?
The duct secretes aqueous/alkaline secretion stimulated by the secretin
The acini secretes enzymatic secretion stimulated by CCK and gastrin
What is the pancreatic exocrine functions?
The duct secretes aqueous/alkaline secretion stimulated by secretin
The acini secretes enzymatic secretion stimulated by CCK and gastrin
What are the secretions of the pancreatic duct?
HCO3, H2O, Ma, K, CL to neutralize the acidic chyme
What are the secretions of the pancreatic acini?
1-Lipase: to digest the lipids and responsible for stool sticks to the commode and will not flush away.
2-Trypsinogen (activated by enterokinase) to digest protein and responsible for autodigestion in pancreatitis.
3-Elastase: in chronic pancreatitis, the first non-invasive test is fecal elastase
4-Amylase: digest CHO
What is the PH of the small intestine?
8.1-8.3 (alkaline)
What are the secretions of the Small intestine?
CCK:
1-Pancreatic acinar cells for enzymatic secretion
2-Contraction of the GB—cholagogue
Secretin:
1-Pancreatic duct cells for aqueous alkaline secretion
2-Secretion from hepatic duct—choleretic
Somatostatin:
1-⬇️Pancreatic secretion exocrine and endocrine
2-⬇️Stomach secretion
If more than 50cm of the small intestine is resected it is called ….
Short bowel syndrome
What are the types of peristalsis?
Primary peristalsis: spontaneously even if there is no food.
Secondary peristalsis: occurs when food enter the bowel
What affects the intestinal motility?
Increased by parasympathetic or vagus (acetylcholine)
Decreased by sympathetic (noradrenaline) as post operative
What is the bile pigment?
Waste product formed from the breakdown of HB of RBCs
How is the bile pigment/stercobilinogen formed and excreted?
In the blood the bilirubin form the RBCs destruction + albumin = Hemobilirubin (indirect/unconjugated)
In the liver the bilirubin in conjugated with 2 glucuronic acid = cholebilirubin (direct/conjugated)
In the large intestine it is reduced by the colonic bacteria = stercobilinogen (urobilinogen)
What is the fate of the bile pigment?
70% is lost in the stool and stercobilinogen oxidized to stercobilin (dark brown)
25% is returned back to the liver via portal vein (entero-hepatic circulation)
5% is returned to blood then to kidney (urobilinogen)
What is the bile salt?
They are Na and K salts of the bile acids (derivates from cholesterol)
