pancreas

what is the job of the pancreas

• secrete bicarbonate

• secrete digestive enzymes

• prevent autodigestion

• release hormones

why is bicarb secretion into the duodenum important

• to neutralize gastric acid entering the duodenum

• provide optimal pH for digestive enzymes

how does the pancreas prevent autodigestion

• enzymes are packaged intracellularly as zymogen granules

• secreted as proenzymes → inactive form of the enzyme

• trypsin will activate but it cannot until it is activated in the duodenum (trypsinogen → trypsin)

what are the main hormones that the pancreas secretes

• insulin

• glucagon

• somatostatin

what 2 things are used to synchronize pancreas secretion of enzymes to the duodenum when food is present

• S cells

• CCK-RF

what stimulates S cells

sensitive to low pH

what happens when S cells are stimulated

secrete secretin → go to pancreas from duodenum → stimulate duct cells → make bicarb to release to duodenum

what stimulates the release of CCK-RF

respond to protein- aromatic amino acids and free fatty acids

are secretin and CCK hormones

yes

is CCK-RF a hormone

no

what type of pancreatic cells make bicarb

duct cells

what is the role of CFTR in the secretion of bicarb

cystic fibrosis regulator: pumps chloride into the lumen so it can be pumped back in, in exchange to release bicarb out

how does CFTR prevent the lumen of the pancreatic duct from drying up

chloride and sodium will bring water back into the lumen when reabsorbed

what is the role of CCK-RF when released

will go and stimulate I cells in the duodenum → secrete CCK → pancreas → stimulate the release of digestive enzymes

what do I cells secrete

cholecystokinin (CCK)

what is the role of CCK

causes vagal reflex arc to be activated which causes the secretion of enzymes from the pancreas and also causes the gall baldder to contract

what will activate pancreatic pro-enzymes

trypsin

where and what is the role of enterokinase

on the brush border of the duodenum; will convert trypsinogen to trypsin

why do you want a neutral pH in the duodenum

• inactivate gastric pepsin

• inc fatty acid and bile acid solubility

• optimize pH for pancreatic and brush border enzymes

• prevent mucosal damage

what is the defect in pancreatic divisum

main pancreatic duct will not join w common bile duct → MPD will try to drain through minor papilla → too small obvi so won’t be very efficenct

what is annular pancreas

band-like ring of pancreas will encircle the duodenum → may constrict duodenum → can cause gastric distention and vomiting

is the pancreas retro- or intraperitoneal

retroperitoneal

is the pancreas an exocrine or endocrine organ

both!

what do acinar cells make

digestive enzymes

• amylase, lipase

• protease

  • trypsin

  • chymotrypsin

what are the cell types in the islets

• alpha

• beta

• delta

• gamma

• epsilon

what is the most abundant cell type in the islets

beta cells

what do alpha cells secrete

glucagon

what do beta cells secrete

insulin

what do delta cells secrete

somatostatin

what do gamma cells secrete

pancreatic peptide

what do epsilon cells secrete

ghrelin

what are the 3 causes of acute pancreatitis

• duct obstruction

• acinar cell injury

• defective intracellular transport

what can cause a pancreatic duct obstruction

• cholelithiasis

• ampullary obstruction

• alcohol use

• ductal concretions

what can cause acinar cell injury

• alcohol

• drugs

• hypertriglyceridemia

• ischemia

• viruses

what can cause defective intracellular transport

• metabolic injury

• alcohol

• duct obstruction

45% of acute pancreatitis is secondary to…

gallstones

35% of acute pancreatitis is secondary to…

alcohol use

what is pancreatitis

pancreatic injury that leads to autodigestion by its own enzymes

what is acute pancreatitis

is reversible pancreatic injury and inflammation

what is chronic pancreatitis

irreversible destruction of pancreas w prolonged injury; get fibrosis and sclerosis of parenchyma w distortion of duct architecture and loss of exocrine/endocrine funx

what are the common causes of acute pancreatitis in the US

• metabolic

  • excessive alcohol

• mechanical

  • gallstones

• infectious

  • mumps

• vascular

• scorpion bites

what does acute pancreatitis look like histologically

has mesenteric fat necrosis

what are the complications of acute pancreatitis

• may lead to liquefactive necrosis of pancreas and adjacent organs

• formation of pseudocyst

• abscess/infection

• hemorrhage

• shock/multi-organ failure

• acute hypocalcemia

what is the mechanism of hypocalcemia is acute pancreatitis

pancreas is inflamed and releasing a bunch of digestive enzymes → lipase being one, will find fat nearby → FFA are freely floating which are TOXIC → Ca will find and bind via saponification → Ca levels dec bc Ca is trapped in fat

what is the #1 cause of chronic pancreatitis in the US

alcohol use disorder

what are the complications of chronic pancreatitis

• chronic abdominal pain, severe unremitting radiating to back

• pseudocysts

• duct obstruction

• malabsorption/steatorrhea

• secondary diabetes

• pancreatic cancer

what organs are affected by cystic fibrosis

• lungs

• liver

• pancreas

• intestines

• male reproductive tract

what is the most common cancer of the pancreas

pancreatic ductal adenocarcinoma

what are the risk factors for ductal pancreatic adenocarcinoma

• chronic pancreatitis

• diabetes

• tobacco

• >50 yrs of age

what is the whipple procedure

remove the parts of tumor involvement: part of the pancreas, duodenum, parts of the common bile duct, and the gall bladder → then anastomoses are made between all the structures → small part of pancreas is still left that will funx

what does pancreatic adenocarcinoma look like histologically

• tumors can invade along nerves

• disorganized invasive glands

• desmoplastic reactive stroma

what are the islet cell neoplasms

• alpha

• g cells

• beta

• delta

• non-beta

neoplasm of alpha cells will lead to what

diabetes mellitus

neoplasm of G cells will lead to what

zollinger-ellison

neoplasm of beta cells will lead to what

hypoglycemia

neoplasm of delta cells will lead to what

• WHDA syndrome

• watery diarrhea

• hypokalemia

• achlorhydria

neoplasm of non-beta cells will lead to what

carcinoid syndrome

what do non-beta cells secrete

serotonin

what is zollinger-ellison syndrome

if there is too much acid being secreted → burn holes in the duodenum → multiple ulcers