Clinical Chemistry: Pancreatic and Gastrointestinal Function Flashcards
GI system
comprises mouth, esophagus, stomach, small and large intestines
digestion
process by which starches, proteins, lipids, and nucleic acids are degraded to molecules for absorption and use in body
pancreas
large gland involved in digestive process, but lies outside of GI system; located behind peritoneal cavity across upper abdomen at level of 1st and 2nd lumbar vertebrae, 1-2 inches above umbilicus; composed of both endocrine and exocrine tissue
endocrine component of pancreas
smaller component; consists of islets of Langerhans which secrete at least four hormones into blood: insulin, glucagon, gastrin, and somatostatin
islets of Langerhans
well-delineated, spherical, or ovoid clusters composed of at least four different cell types that secrete pancreatic hormones
exocrine component of pancreas
produces digestive fluid rich with enzymes in pancreatic acinar cells (grape-like clusters), which line pancreas and are connected by small ducts; proteins (trypsin, chymotrypsin, etc.), carbs (amylase), and fat (lipase and lecithinase); secretes fluid into ducts that empty into duodenum-also contains bicarbonate to neutralize stomach acid going into the duodenum
trypsin and chymotrypsin
pancreatic enzymes that digest proteins
amylase
pancreatic enzymes that digest carbs
lipase and lecithinase
pancreatic enzymes that digest fats
cystic fibrosis
disease of pancreas and mucoviscidosis; inherited autosomal recessive dysfunctino of mucous and exocrine glands throughout body; manifests as intestinal obstruction in newborn, excessive pulmonary infections in childhood, and pancreatogenous malabsorption in adults; causes ducts and acini to dilate and convert into small cysts filled with mucus, preventing secretions from reaching duodenum
pancreatic carcinoma
fourth most frequent form of fatal cancer; causes about 38,000 deaths each year in the US, which represents about 7% of all deaths from malignant neoplasms; most arise as adenocarcinomas of ductal epithelium
pancreatitis
inflammation of pancreas caused by autodigestion of pancreas as a result of reflux of bile or duodenal contents into pancreatic duct; leads to acute edema, cellular infiltration, intrahepatic and extrahepatic pancreatic fat necrosis
malabsorption syndrome
abdominal bloating and discomfort, frequent passage of bulky, malodorous feces, and weight loss
steatorrhea
failure to digest or absorb fats leading to greasy appearance to feces
amylase, lipase, secretin, CCK, fecal fat, trypsin, and chymotrypsin
tests used to assess pancreatic function
gastrin, insulin, and glucose
used to assess endocrine-related pancreatic disorders
bilirubin
assesses changes associated with extrahepatic obstruction
secretin/CCK
direct determination of the exocrine secretory capacity of the pancreas; intubation of duodenum without contamination by gastric fluid, which neutralizes bicarb; 6-hour fast; decreased flow: pancreatic obstruction and increase in enzyme concentrations; low bicarb and enzyme concentrations: cystic fibrosis, chronic pancreatitis, pancreatic cysts, calcification, and edema of the pancreas
fecal fat analysis
fecal lipids are derived from four sources: unabsorbed ingested lipids, lipids excreted into intestine (bile), cells shed into the intestine, and metabolism of intestinal bacteria
sweat sodium and chloride concentrations
test used to diagnose cystic fibrosis; significantly elevated in 99% of affected patients
amylase
serum enzyme most commonly used to detect pancreatic disease (pancreatitis); rises in a few hours and peaks at 24 hours; significant increases in 75% of patients; increased in mumps, cirrhosis, ruptured ectopic pregnancy, and others
lipase
produced by the acinar cells of pancreas; more sensitive indicator-stays elevated longer; also increased in bone fractures