Digestive System: The Pancreas

Front 1

Basic Anatomy of the Pancreas

Back 1

-Endocrine Fxn: insulin & glucagon via islets of langerhaan cells
-Exocrine Fxn: 2 general fxns=
1. it is source of HCO3 to neutralize gastric acid
2. source of many digestive enzymes
-gross visualization reveals: head, body, tail
-microscopic: pancreatic islets & acinar cells (exocrine)

Front 2

Pancreatic Juice

Back 2

-secreted by pancreas to duodenum
-HCO3 and digestive enzymes
-pH 7.6-8.2
-travels via main pancreatic duct
-controlled by sphincter of oddi
~1500ml of pancreatic juice secreted per day (almost all recycled)
-bile & intestinal juices are also neutral or alkaline to neutralize the gastric acid raising the duodenal to 6-7

Front 3

Enzymes included in the pancreatic juice:

Back 3

-pancreatic amylase
-pancreatic lipase
-colipase
-trypsinogen
-chymotrypsinogen
-procaroxypeptidase
-proelastase
-ribonuclease
-deoxyribonuclease

Front 4

Where Pancreatic Enzymes are activated?

Back 4

-proteases are secreted as inactive
-trypsinogen converted to active enzyme trypsin by brush border enzyme enterokinase (enteropeptidase) when enters duodenum
-trypsin converts:
>chymotrypsinogen into active chymotrypsin
>procarboxypeptidase into active carboxypeptidase
>proelastase into active elastase
-enterokinase deficiency can occur as congenital abnormality, leads to protein malnutrition

-deactivated by trypsin inhibitor (cancels out cascade effect of tyrpsin)

Front 5

Regulation of Pancreatic Juice Secretion

Back 5

-prim under hormonal control
-secretin: acts on pancreas to cause copious amounts of alkaline pancreatic juice rich in HCO3 & poor in enzymes
-CCK on other hand stim pancreatic juice rich in enzymes & low in HCO3
-stim of parasymp fibers w/in vagus nerves also cause secretion of a small amt of pancreatic juice rich in enzymes (much less potent than secretin)
-some evidence of vagally-mediated reflex secretion in response to sight/smell of food

Front 6

Pancreatitis

Back 6

-acute: severe, life-threatening disorder assoc w/ escape of activated enzymes into pancreas & surround tissues
-small amts of panc. dig. enzymes normally leak into circulation, but in acute pancreatitis the circ levels of digestive enzymes rise markedly
-measure of plasma pancreatic amylase or pancreatic lipase is therefore of value in diagnosing problems assoc w/ inflam and necrosis of pancreatic acinar cells
-enzymes cause fat necrosis (autodigestion) of pancreas & produce fatty deposits in ab cavity w/ hemorrhage from necrotic vessels
-most result from gallstones (stones in common bile duct)
-or alcohol abuse

Front 7

Gallstones

Alcohol Use

Other Associations

Back 7

-biliary tract obstruction due to gall stones
-pancreatic duct obstruct or biliary reflux activate the enzymes in pancreatic duct system

-alcohol exerting action are unknown
-potent stim of pancreatic secretions
-cause partial obstruction of sphincter of oddi

-assoc w/ hyperlipidemia, hyperparathyroidism, infections (viral), abdominal & surgical trauma
-steroid drugs & thiazide diuretics

Front 8

Symptoms of Pancreatitis

Back 8

-severe epigastric & abdominal pain that radiates to back
-pain aggravated when person is lying supine
-less severe when person is sitting/leaning forward
-hypoactive bowel sounds
-loss of large V of fluid into ab cavity
-tachycardia
-hypotension
-cool & clammy skin
-fever
0hypocalcemia: precipitate of serum Ca in areas of fat necrosis
-mild jaundice appear after 1st 24 hours becuase of biliary obstruction