Pancreatic Function Flashcards
What does the GI system contain
mouth, esophagus, stomach, small intestine, large intestine
What process does is this describing?
The process by which starches, proteins, lipids, nucleic acids, other complex molecules are degraded for absorption and use in the body
Digestion (small intestine mostly)
This is a description of which organ:
Large gland involved in digestion
Not in the GI tract
Exocrine tissues: production of enzymes used in digestive process
Endocrine tissues: production of insulin and glucagon
Pancreas
This is the physiology of which organ?
Weights 70-105 g
Second in size to the liver
Behind the peritoneal cavity
About the level of first and second lumbar vertebrae
Pancreas
What area of the pancreas is this describing:
Liver and pancreas combine enzymes and bile here
Formed by the joining of the pancreatic duct and the common bile duct
Ampulla of Vater
Name and describe the TWO distinct tissues of the pancreas
Endocrine
Hormone releasing
2% total tissue
Consists of islets of Langerhans
Exocrine
Enzyme secreting
98% tissue
Secretes 1.5-2 L/day of fluid—digestive fluid
What cell does this describe and which pancreas tissue is this a part of?
Well-delineated, spherical, or ovoid clusters of 5 cell types
Secrete 5 hormones
Alpha—glucagon
Beta—insulin
Delta—somastostatin
Gamma– pancreatic polypeptide hormones
Epsilon–ghrelin
Hormones secreted into surrounding blood vessels and transported to tissues/organs
Islet Cells of the ENDOcrine Tissue
What cell does this describe and which pancreas tissue is this a part of?
Produce the digestive fluid
Connected by small ducts—join together into larger ducts (grape like structure)
Major pancreatic duct and smaller accessory duct
Normal, protein rich pancreatic fluid
Clear, colorless, watery
Alkaline pH up to 8.3
Caused by high concentration of sodium bicarb used to neutralize gastric fluid (hydrochloric acid)
Bicarbonate and chloride concentrations vary reciprocally
Total about 150 mmol/L
Fluid has same concentrations of K and Na as serum
Acinar cells (grape-like clusters) of the EXOcrine tissue
Exocrine digestive enzymes work on what 3 major classes of food?
Proteins
Carbohydrates
Fats
What are the digestive enzymes of the acinar cells in the pancreas exocrine tissue?
Proteolytic enzymes: trypsin, chymotrypsin, elastase, collagenase, leucine aminopeptidase, and some carboxypeptidases
Lipid-digesting enzymes: lipase, lecithinase
Carbohydrate-splitting pancreatic amylase
Several nucleases: ribonucleases—separate nitrogen containing bases from their sugar phosphate strands
What is under both nervous and endocrine control?
Pancreatic activity
This can secrete pancreas fluid when food is seen or smelled
Vagus Nerve
What is:
Responsible for alkaline pancreatic fluid that protects lining of intestine
Synthesized in response to acid stomach contents
Contains few digestive enzymes
Secretin
What is produced by cells of intestinal mucosa and responsible for release of enzymes from acinar cells
Cholecystokinin (CCK)—formerly called pancreozymin
What 3 disease states cause 95% of medical attention to the pancreas?
Cystic Fibrosis
Pancreatic Carcinoma
Pancreatitis
All 3 can:
Result in severely diminished pancreatic exocrine function
Significantly compromise digestion and absorption of nutrients
What pancreatic disease does this describe:
Inherited autosomal recessive disorder
Dysfunction of mucous exocrine glands
Most common Caucasian in U.S.
1 in 6000 live births
High frequency in Brittany, France
10% carry gene
CFTR gene—chromosome 7
Newborn screening standards
Cystic Fibrosis
What pancreatic disease does this describe:
Initial presentation varies
Intestinal obstruction: newborn
Excessive pulmonary infections: childhood
Pancreatogenous malabsorption: adults–uncommon
Causes small and large ducts and the acini to dilate and convert into cysts filled with mucous
Prevents pancreatic secretions from reaching duodenum
Can cause a plug that may cause bowel obstruction
Cystic Fibrosis
What pancreatic disease does this describe:
4th most frequent form of fatal cancer
7% of all deaths from malignant neoplasms
More males vs females
More blacks./Af.Am. vs other races
5 yr survival 6%
Most die within 1 yr
Pancreatic Carcinoma
What pancreatic disease does this describe:
Adenocarcinomas of ductal epithelium—most common origin
Rich supply of nerves—very painful
Delayed diagnosis if tumor is in the neck or body
Head—symptoms earlier—near bile duct
Signs: jaundice, weight loss, anorexia, nausea
Pancreatic Carcinoma
What effects do islet cell tumors have in a patient with pancreatic carcinoma?
Affect endocrine capability
Hyperinsulinism—low blood sugar
Hypoglycemic shock
These are the tests recommended for which pancreatic disease: pancreatic polypeptide (PP), other biochemicals, glucagon and gastric levels for gastrointestinal evaluations
Pancreatic Carcinoma
What two secretions are pancreatic tumors capable of?
Gastrin secreting
Gastrinomas
Cause Zollinger-Ellison Syndrome
Duodenal in origin
Symptoms: watery diarrhea, recurring peptic ulcer, significant gastric hypersecretion, hyperacidity
Glucagon secreting
Rare
What pancreatic disease matches this description:
Inflammation of the pancreas caused by autodigestion of the pancreas
Result of bile or duodenal contents into the pancreatic duct
Pancreatitis
What pancreatic disease causes these pathological changes:
Acute edema, cellular infiltration—leads to necrosis of acinar cells, hemorrhage as possible result of necrotic blood vessels, intra- and extra-hepatic pancreatic fat necrosis
Pancreatitis
What pancreatic disease has the following features:
Acute—no permanent damage
Chronic—irreversible injury
Relapsing/recurring—acute or chronic, common in midlife, painful episodes with nausea/vomiting, often associated with alcohol abuse, biliary tract diseases
Pancreatitis
The below factors are associated with the acute form of what pancreatic disease?
Mumps
Biliary tract obstruction
Pancreatic tumors
Tissue injury
Atherosclerotic disease
Hereditary pancreatitis
Immunologic factors: post-renal transplant, hypersensitivity
Chronic—similar to acute—alcohol consumption most common predisposing factor
Pancreatitis
These are the symptoms of what pancreatic disease?
Severe abdominal pain
Generalized or upper quadrant
Radiates toward back or down the flank
Acute Pancreatitis
These are the lab findings of the acute version of what disease?
Increased: amylase, lipase, triglycerides, hypercalcemia
Can see hypocalcemia rarely
Due to sudden removal of calcium by calcium fixation by fatty acids liberated by lipase action on triglycerides
Acute Pancreatitis
Pancreatitis, Pancreatic Carcinoma and Cystic Fibrosis are the essence of what syndrome?
Mal-absorption Syndrome
This is a general description of:
Abdominal bloating and discomfort
Frequent passage of bulky malodorous feces
Weight loss
Steatorrhea: failure to digest or absorb fats
Gives “greasy appearance to feces (>5 g fecal fat/24 hrs)
Mal-absorption Syndrome
These are all characteristics of:
Typically involves abnormal digestion or absorption of proteins, carbohydrates, polysaccharides, other complex molecules, and lipids
Severely deranged absorption and metabolism of electrolytes, water, vitamins (fat soluble A,D,E,K) and minerals
Can involve a single substance: ex. Vit B12—megaloblastic anemia
Can also be caused by biliary obstruction or diseases of small intestine
Mal-absorption Syndrome
Gastrin, insulin, and glucose are tests run on which pancreatic tissue?
Endocrine Tests
What is this measuring?
Suspected with increased Amylase and Lipase
Can be measured indirectly or directly
Exocrine Pancreatic Function
This type of testing has these characteristics:
Include those used for detection of malabsorption
Qualitative fecal fat analysis, fecal elastase, fecal chymotrypsin, bilirubin
Indirect
These characteristics describe what type of testing?
Most sensitive
Performed on actual pancreatic secretions
Advances in imaging: MRI and MRCP (magnetic resonance cholangiopancreatophraphy) has reduced the need for the tests
Endoscopy or the Dreiling tube method after stimulation with secretin and/or cholecystokinin (CCK)
Combined secretin/CCK test done at specialized centers to simultaneously assess ductal and secretory capacity
Direct
What test fits this description?
Hormone secreted by cells in the stomach
Stimulates the release of bile into the intestine
Stimulates secretion of enzymes by the pancreas
Direct determination of the exocrine secretory capacity of the pancreas
Intubation of duodenum with out contaminating with gastric fluid
Secretions are collected and measured
pH, secretory rate, enzyme activity and bicarb are measured
Total volume affects results
Pancreatic obstruction: decreased pancreatic flow and increased enzymes
Low bicarb and enzymes: CF, chronic pancreatitis, pancreatic cysts, calcification, and edema of pancreas
Cholecystokinin Test (CCK)
What are these?
Unabsorbed ingested lipids
Lipids excreted into the intestine
Cells shed into the intestine
Metabolism on intestinal bacteria
The 4 sources of fecal lipids
A lipid rich diet doesn’t usually exceed excreting how many grams per day
7 g/day
The below description is the composition of what:
60% fatty acids
30% sterols, higher alcohols and carotenoids
10% triglycerides
Small amounts of cholesterol and phospholipids
Normal fecal lipids
Increased fecal fat can be caused by what issue?
biliary obstruction
What issue is associated with exocrine pancreatic insufficiency or disease of small intestine
Severe steatorrhea
This is a description of what test:
Neutral fats (trig) and other lipids: stain yellow-orange to red with Sudan III
Must be heated
Normal has 40-50 small lipid drops/hpf
Steatorrhea: >100 small drops and large drops may be present
Sudan Staining
This is a description of what test:
Definitive test for steatorrhea
72-hr stool collection (up to 5 d)
Gravimetric and titrimetric methods
Lipid rich diet for at least 2 days
Measure only saponifiable fatty acids
20% lower results
Quantitative Fecal Fat Analysis
This is a description of what test:
Emulsify entire fecal sample in water
Fatty acid soaps (Ca and Mg salts of fatty acids) are converted to free fatty acid—followed by extraction of most of the lipids into an organic solvent
Gravimetric Method for Fecal Fat Determination
What fecal enzyme fits this description:
Non-invasive indirect indicator of moderate and severe exocrine pancreatic dysfunction
Chymotrypsin-like enzyme secreted by pancreas
In exocrine pancreatic insufficiency, fecal fat increased, fecal enzymes decreased
RR for normal: >200 ug/g
Moderate insufficiency 100-200 ug/g
Severe insufficiency <100 ug/g
Fecal elastase-1
These are the defining characteristics of what enzyme?
Less sensitive and specific
Can be affected by supplements
Fecal chymotrypsin
These are the defining characteristics of what test:
CF patients have reduced ability to resorb Cl from sweat
Due to dysfunction of the chloride transporter (CFTR gene product)
Difficult test to perform
2-5 fold increase in sweat Na and Cl are diagnostic of CF in kids
Nothing else causes sweat Cl over 80 mmol/L
Doesn’t distinguish hetero- from homozygous carriers
Sweat Chloride Testing
These are defining characteristics of what serum enzyme:
Almost exclusively pancreatic test
More sensitive, specific, accurate
Increases within 24 hrs acute pancreatitis
Persists for 8-14 days from reabsorption
Not cleared like amylase
Lipase
These are defining characteristics of what serum enzyme:
Alternate
Significant increases in 75% of patients increases within 3-6 hours
Peak at 24 hrs
Clearance by the kidneys—returns to normal 3-5 days
Urine amylase more sensitive indicator
Magnitude doesn’t correlate with severity
Also measured in saliva and pancreatic fluid
Amylase
This is a description of what process?
Useful in detecting minor or intermittent increases in serum levels
RR <3.1%
Significantly increased 8-9% seen in acute pancreatitis, burns, sepsis, diabetic ketoacidosis
Renal clearance of Amylase
These situations cause an increase in what?
Opiate administration, pancreatic carcinoma, intestinal infarction, obstruction or perforation, pancreatic trauma
Both Amylase and Lipase
These disorders cause an increase in what?
Mumps, cholecystitis, hepatitis, cirrhosis, ruptured ectopic pregnancy, macroamylasemia
Amylase
Bone fractures and fat embolisms cause an increase in what?
Lipase
This is a description of what test:
Peptide hormone, enhances gastric growth, gastric motility, secretion of hydrochloric acid
Present in G cells of gastric antrum and duodenum
Basal level and stimulation done
Typically done to diagnose Zollinger-Ellison syndrome (gastrinoma—increased stomach acid leading to ulcers)
Gastric Secretion
Characteristics of what test:
Clinical chem focuses on evaluation of absorption and its various disease states
Include: tropical sprue, celiac disease, Whipple’s disease Crohn’s disease, primary intestinal lymphoma, small intestinal resection, intestinal lymphangiectasia, ischemia, amyloidosis, giardiasis, and lactose intolerance
Intestinal Function
Description of what test:
Disaccharide sugar composed of glucose and galactose present in mammalian milk
Lactase: enzyme produced in small intestine that digests lactose
Loss or deficient lactase in adults is normal
Lactose intolerance: abdominal cramps, bloating, diarrhea
Lactose tolerance test
Largely replaced by a breath test
Lactose
Description of what test?
Exogenously administered simple monosaccharide sugar
Not normally present in blood
Doesn’t require pancreatic lytic enzymes
D-xylose
Description of what test?
Phytochemicals
Main precursors of Vit A
6 most common carotenoids account for 90%
Decreases seen: malabsorption, starvation, diet, fever
Carotenoids
