Gastrointestinal II Flashcards
What are the 2 functions/divisions of the pancreas?
Endocrine
Exocrine
What 2 hormones make up the Endocrine Pancreas?
Insulin
Glucagon
What does the Exocrine pancreas produce?
Pancreatic Juice
What makes up pancreatic juice?
Bicarb (neutralizes gastric acid)
Digestive enzymes
What is pale in a pancreatic slide?
Islets, alpha cells (insulin and glucagon)
What is darker in a pancreatic slide?
Exocrine cells
*90%
What is the pH of pancreatic juice?
7.6-8.2
How does pancreatic juice exit the pancreas into the duodenum?
Main Pancreatic Duct
How much pancreatic juice is secreted each day?
1500 mL
What is the pH of duodenal contents after exposure to pancreatic juice?
6.0-7.0
What are the 3 control points for Bile and Exocrine secretions from the Pancreas?
Bile duct sphincter
Pancreatic duct sphincter
Sphincter of Oddi
T/F
Sphincter of Oddi controls release of bile and pancreatic juice.
True
What is the opening of bile/pancreatic juice into the duodenum?
Papilla of Vater
Pancreatic juice enzymes that break down carbs and lipids include:
Pancreatic amylase
Pancreatic lipase
Colipase
4 Proteases in Pancreatic juice.
Trypsinogen
Chymotrypsinogen
Procarboxypeptidase (A/B)
Proelastase
2 enzymes in pancreatic juice that break down nucleic acids:
Ribonuclease
Deoxyribonuclease
What catalyzes Trypsinogen > Trypsin?
Enterokinase
aka enteropeptidase
Where is enterokinase found?
Function?
Brush border (enzyme) Trypsinogen > Trypsin
What enzyme converts chymotrypsinogen, proelastase, and procarboxypeptidase (A/) into its active forms?
Trypsin
*via Enterokinase
What congenital abnormality can lead to protein malnutrition?
Enterokinase deficiency
As a protective measure, what does pancreatic tissue contain?
Trypsin inhibitors
2 hormones that stimulate pancreatic secretion:
Difference in secretion?
Secretin - high HCO3-, low in Enzymes
CCK - high enzyme, low HCO3-
Aside from CCK, what is another high enzyme pancreatic stimulant?
Vagal parasympathetic
*reflex, much lower amount than CCK
T/F
Small amounts of pancreatic digestive enzymes normally leak into the circulation
True
What does increased plasma pancreatic amylase and lipase indicate?
What’s wrong at the level of the tissue?
Acute pancreatitis
Inflammation/necrosis pancreatic acinar cells
What do enzymes do in pancreatitis to pancreatic tissue?
Fat necrosis
What do most cases of acute pancreatitis result from?
2 things
Gallstones
Alcohol abuse
What condition might activate pancreatic enzymes whilst still in pancreas?
Gall stones/pancreatic obstruction
exact mechanism unknown
T/F
Alcohol damage to pancreas by unknown mechanism
True
What 2 effects does alcohol have on the pancreas?
Stimulates secretions
Contracts Sphincter of Oddi
Other than alcohol and gallstones, what is acute pancreatitis associated with?
(5 things)
Hyperlipidemia Hyperparathyroidism Infections (viral) Trauma (abdominal/surgical) Drugs (steroids/thiazide diuretics)
Tachycardia, hyptotension, cool and clammy skin, and fever and indicative of what?
(also hypocalcemia and jaundice)
Acute pancreatitis
What is the most common symptom of acute pancreatitis?
Severe epigastric and abdominal pain
radiates to the back
What does “pancreatic cancer” usually refer to?
Ductal Adenocarcinoma
What cell does more than 95% of malignant neoplasms in the pancreas arise from?
Exocrine cells
What are the most common symptoms of exocrine pancreatic cancers?
Pain
Jaundice
Weight loss
How are cancers in the head of the pancreas different from those in the tail?
4 things
most numerous (60-70%)
jaundice
steatorrhea (fat in feces)
weight loss
What are 3 major risk factors for pancreatic cancer?
Smoking
High mass/low activity
Chronic pancreatitis
*also 5-10% familial risk
What is the most common lethal genetic disease among caucasions?
Cystic Fibrosis
What causes Cystic Fibrosis symptoms in cell?
Genetic?
Cl- channel defect
CTFR gene
What does the Cl- channel defect cause in Cystic Fibrosis?
Exocrine gland malfunction
- increases viscosity in mucus and Cl- concentration in sweat and tears
- *sweat test for diagnosis
3 Clinical manifestations of Cystic Fibrosis.
Chronic pulmonary disease
Pancreatic insufficiency
Meconium ileus
What is a liver lobule?
Hexagonal structure of Portal triads, Sinusoids, and Central vein
How many triads (tetrads) are in a liver lobule?
6
What 4 structures are in a triad
Portal Vein
Hepatic artery
Bile duct
Lymphatic
What travels from the Portal vein to the Central vein in a liver lobule?
Sinusoid
Where are the Hepatic macrophage?
Another name?
Sinusoid lining
Kupffer cells
What runs parallel to the sinusoids?
Bile canaliculi
*drain bile produced by hepatocytes
What is the term for the arrangement of hepatocytes within lobules?
Hepatic cords
*sinusoids separate
What is unique about the liver’s bloodflow?
Mixing of blood from Hepatic artery and Portal vein in the Central vein in lobes
Trace blood from the sinusoidal mixing:
Central vein
Hepatic vein
Inf. vena cava
Right atrium
What’s special about the fenestrated endothelium in sinusoids?
No basement membrane
*blood washes freely over hepatocytes
Where does blood wash freely over hepatocytes?
2 names
Space of Disse
perisinusoidal space
Sinusoidal blood flows in what direction?
Toward Central Vein
What could happen in pressure increases drastically in the portal vein and sinusoids?
Ascites
Because of the spaces of Disse, the liver must…
have high Lymph flow
What is the term for drugs entering the portal vein first?
First Pass Effect
Normal pathway into Bile duct:
Rt/Lt Hepatic ducts
Common Hepatic Duct
Gall bladder or Bile duct
What % of liver cell weight can be glycogen?
8%
*more than muscle at 1-3%, but less total glycogen
T/F
Protein degradation occurs alost exclusively in the liver
True
What class of enzymes is required for deamination? What are they (2)?
Aminotransferases
AST and ALT
Other than deamination, what can AST and ALT do?
Synthesize non-essential AA’s within hepatocytes
What can too much ammonia in the blood cause?
Hepatic coma
Hepatic encephalopathy
2 terms for too much urea in the blood.
Azotemia
Uremia
*toxic to other tissues
What is the normal Blood Urea Nitrogen (BUN) level?
5-26 mg/dL
T/F
GI bleeding can cause Uremia
True
*due to bacteria creating nitrogenous wastes
4 contents in the protein coated chylomicron:
FFA
Cholesterol
Phospholipids
TG’s
What is the important liver enzyme in endogenous cholesterol synth?
HMG-CoA reductase
What is the only way the body can eliminate excess cholesterol?
Bile
In what 2 conditions is Ketogenesis likely to occur?
Fasting
Type I diabetes
What hormones are degraded by the liver?
All steroid hormones
T3 and T4
Name 4 steroid hormones degraded by the liver:
Cholesterol
Aldosterone
Cortisol
Progesterone
How is iron stored in the liver?
Before stored is called?
Ferritin
Apoferritin
How is iron taken up in the stomach?
Transferred in the blood?
Gastroferritin
Transferrin
What vitamins are stored in large quantities in the liver?
A
B12
D
What is the most important enzyme system for metabolism/drug detox in the liver?
Cytochrome P450
What happens between Phase I and Phase II in drug pathways?
Metabolism
What is the difference between Phase I and Phase II in drug metabolism?
Phase I - drug unchanged, modified, or inactive
Phase II - Conjugate is eliminated
Cytochrome P450 enzymes are denoted by…
CYP (letter, number, letter)
What type of enzyme is Cytochrome P450?
Phase I
Conjugative enzymes are what type?
Phase II
What do conjugative enzymes do?
How?
Make metabolites more polar/hydrophilic
Endogenous substrate added
What is the most common/important conjugation rxn?
Glucuronidation
What can lead to decreased metabolism of drugs?
CP 450 inhibition
What can increase metabolism of drugs?
CP 450 induction
What step of Vitamin D activation is taken in the Liver?
Cholecalciferol > 25-Hydroxycholecalciferol
*Hydroxylation
What are the 3 major plasma proteins?
Where are they formed?
Albumin (liver)
Globulin (liver, lymphoid)
Fibrinogen (liver)
T/F
Albumin supplies 50% buffering capacity of the blood.
False
15%
What blood clotting factors aren’t made in the liver?
III
IV
XIII
What are the 4 organic constituents of Bile?
%’s?
bile salts - 50
phospholipids - 40
cholesterol - 4
bile pigments (like bilirubin) - 2
Where does bile pick up electrolytes and water?
Bile duct lining secretions
What are the 2 primary bile acids produced by hepatocytes?
Cholic acid
Chenodeoxycholic acid
What are the secondary bile acids a portion of primaries are converted into by intestinal bacteria?
Deoxycholic acid
Lithocholic acid
Why is bile converted into bile salts?
Amphipathic
both hydrophobic/hydrophilic
What is converted into a Bile Salt?
with what?
Secondary bile acids
(deoxycholic acid and Lithocholic acid)
Glycine and Taurine
What is the most common Phospholipid in the bile?
Lecithin
also amphipathic
What accounts for the majority of cholesterol breakdown in the body?
Synth bile acids
500 mg/day
T/F
cholesterol is eliminated in the bile as a waste product
True
*but only some
What is the waste product of hemoglobin degradation?
Bilirubin
How is free bilirubin (Unconjugated bilirubin) transported in the blood?
Albumin
What does the liver do with Free Bilirubin?
Conjugates
Excretes into bile
What is attached in the conjugation of Bilirubin?
What enzyme catalyzes this rxn?
Glucuronic Acid
Glucoronyl transferase
What is more water soluble, conjugated or unconjugated bilirubin?
Conjugated
T/F
Bile contains lipophilic drug and antigen-antibody complex waste products
True
What doesn’t flow into the central canal?
Bile ducts
3 steps of Bile Synthesis:
Secretion into canaliculi
Pick up HCO3-, ions, and water
(this accounts for 900 mL/day)
1/2 bile stored in Gall Bladder btwn meals
By how much is Bile concentrated in the Gall Bladder?
10-20 fold
T/F
Bile that reached the duodenum is a mixture between dilute and concentrated
True
from gall bladder and liver
What are the 2 important functions of Bile?
Alternate Excretory route (other than kidney)
Lipid Digestion/Absorption
bile salts and Lecithin
What duct connects the Hepatic Duct to the Gallbladder?
Cystic Duct
CCK 2 actions concerning bile:
Contracts gall bladder
Relaxes Sphincter of Oddi
What stimulates ion and water secretion in bile ducts?
Secretin
What neurotransmitter contracts Gall Bladder via Parasympathetic response?
Ach
What mechanism dominates during the “interdigestive” periods concerning the gall bladder?
2 functions?
SNS Beta-2
Fills gall bladder and closes sphincter of Oddi
What is the term for inflamed Gall bladder wall?
Cholecystitis
Steady severe pain URQ radiating to shoulder or back indicates what?
*also fever, leukocytosis, nausea, vomiting, anorexia
Acute cholecystitis
*gallstone disease
Chronic cholecystitis is almost always associated with what?
Gall stones
What is the most common complication associated with Cholecystitis?
Gangrene (20%) followed by Perforation (2%)
Presence of gallstones is called:
Cholelithiasis
Most gallstones in US and Europe (90%) are what type?
Cholesterol stones
What 3 factors are involved in gallstone formation?
Bile Stasis (from stone in gall bladder)
Supersaturation
Inflammation (cholecystitis)
What size gallstone usually passes?
less than 8 mm
What can large gallstones cause?
Jaundice
obstructed flow
What increases intra-gallbladder pressure and causes RUQ pain?
(pain can radiate)
Biliary colic
T/F
Oral contraceptives and rapid weight loss can cause gallstones
True
T/F
Pregnancy can cause cholelithiasis
True
T/F
Cholecystectomy can cause duodenal emptying to decrease
False
*common bile duct dilates, more bile after meals
What is the cure for Physiological Jaundice of the newborn?
Light breaks bili
Why would Liver disease cause osteomalacia?
No VitaD
No Ca++
Bilirubin levels in Hepatic disease would be what in the blood?
Increased
UN-bili and CON-bili
In liver disease, what would the Albumin and Total protein levels be in the blood?
Low
*not making
T/F
Gamma-glutamyl transferase decreases in liver failure
False
What does Prothrombin time do in liver failure?
Increase
*no more clotting factors
UN-bili increases
CON-bili same
Pre-hepatic disease
UN-bili increases
CON-bili increases
Intra-hepatic disease
Post-hepatic disease
What tumor can cause an increase of UN-bili and CON-bili?
Pancreatic tumor (in head)
