2C A&P and Pathology of the Pancreas Flashcards
What does the endocrine part of the pancreas produce?
Insulin, glucagon, plasma glucose regulation
What does the exocrine part of the pancreas produce?
Pancreatic juice
What are the two function of pancreatic juice?
Source of bicarbonate to neutralize gastric acid. Source of many digestive enzymes
What is the pancreas shaped like?
Like the letter L
Where is the head of the pancreas? Tail?
Short arm of L close to the duodenum. The tail is the long arm of the L furthest from the small instenstine
What are the lighter staining areas of pancreatic tissue?
Islets of Langerhans (endocrine)
What kinds of cells are in the pancreatic islets?
Alpha, Beta, and Delta cells
What does the exocrine part of the pancreas look like histologically?
Stains dark
What percent of the pancreas consists of exocrine cells? Endocrine cells?
90% exocrine, 10% endocrine
What are exocrine cells surrounded in?
Pancreatic acini
What does the pancreatic juice have a lot of?
Bicarb and enzymes
What is the typical pH of pancreatic juice?
7.6-8.2
How much pancreatic juice is secreted per day?
About 1500 mL
How does the pancreatic juice get to the duodenum?
Via the man pancreatic duct
Is pancreatic juice alkaline or acidic?
Alkaline
What else, besides pancreatic juice helps to neutralize the gastric acid in the duodenum?
Bile and intestinal juices are also neutral or alkaline
What pH are the duodenal contents raised to?
6.0 to 7.0
Which duct merges with the main pancreatic duct?
Common bile duct
Before reaching the sphincter of Oddi, does the bile duct and pacreatic duct each have their own spincters?
Yes, sir!
What does the sphincter of Oddi do?
Regulates the flow thru the papilla of vater
What is the opening into the duodenum from the common bile duct called?
Papilla of Vater
What enzymes are included in the pancreatic juice?
Pancreatic amylase, pancreatic lipase, colipase, trypsinogen, chymotrypsinogen, procarboxypeptidase (A/B), proelastase, ribonuclease, deoxyribonuclease
Which four enzymes of pancreatic juice are proteases (breakdown proteins)?
Trypsinogen, chymotrypsinogen, procarboxypeptidase (A/B), proelastase
What are proteases initially secreted as?
Proenzymes
What is the brush border enzyme that activates trypsinogen into trypsin?
Enterokinase
What does trypsin do?
Converts his proenzyme protease friends into enzymes - Chymotrypsinogen into chymotrypsin; proelastase into elastase; procarboxypeptidase into carboxypeptidase
T/F Enterokinase deficiency can occur as a congenital abnormality
T
Why are trypsin inhibitors normally produced in pancreatic tissue?
Since trypsin can cause a chain reaction activating several active enzymes too soon, this is a way to prevent these enzymes from digesting the pancreas
How do we control the flow of pancreatic juice?
Hormonally and neurally?
Pancreatic juice is primarily under what control?
Hormonal
What does secretin do?
Acts on the pancreas to cause copious secretion of a very alkaline pancreatic juice that is rich in bicarb and low in enzymes
What does CCK do?
Stimulates production of pancreatic juice rich in enzymes and low in bicarb
Which nervous system also causes secretion of a small amount of pancreatic juice rich in enzymes?
ParaSNS
Which is a more potent stimulator of pancreatic juice rich in enzymes, CCK or ParaSNS?
CCK
What is acute pancreatitis?
A severe, life threatening disorder associated with the escape of activated pancreatic enzymes into the pancreas and surrounding tissues
Do pancreatic digestive enzymes normally leak into the circulation? So why does acute pancreatitis occur
Yes. However, during acute pancreatitis the circulating levels of the digestive enzymes rise markedly
How is pancreatitis measured in the plasma?
Pancreatic amylase or pancreatic lipase is of value in diagnosing problems associated with inflammation and necrosis of pancreatic acinar cells
What is fat necrosis?
Autodigestion of the pancreas that produces fatty deposits in the abdominal cavity w/ hemorrhage fro the necrotic vessels
What do most cases of acute pancreatitis result from?
Gallstones (stones in the common bile duct) or alcohol abuse
Where do galls stones form?
Liver where bile is made or in the gall bladder where bile is stored. Most of the time they form in the gall bladder
Where does the gall stone have to get stuck to get pancreatitis?
At the opening to the duodenum
Why is it a problem is bile backs up into the pancreas?
There are some things in the bile that can activate the pancreatic enzymes in the pancreatic juice - biliary reflux
What is the most common initial symptom of pancreatitis?
Severe epigastric and abdominal pain that radiates to the back. Pain is aggravated when person is supine
What is an important disturbance related to acute pancreatitis?
Loss of large volume of fluid into the abdominal cavity
What are some other symptoms of pancreatitis?
Tachycardia, hypotension, cool and clammy skin, fever. Signs of hypocalcemia may develop. Mild jaundice many appear after the first 24 hours
What does pancreatic cancer usually refer to?
Ductal adenocarcinoma of the pancreas.
Where do more than 95% of malignant neoplasms of the pancreas arise?
From exocrine elements and are referred to as exocrine pancreatic cancers
What are the most common presenting symptoms in pts with exocrine pancreatic cancer?
Pain, jaundice, and weight loss
Where are 60-70% of exocrine pancreatic cancers localized? Where is the rest?
In the head of the pancreas. 20-25% are in the body/tail and the remainder involve the whole organ
Compared to tumors in the body and tail of the gland, pancreatic head tumors more often present with what?
Jaundice, steatorrhea, and weight loss
What is the only potentially curative treatment for exocrine pancreatic cancer?
Surgical resection
What is the 5 year survival following pancreatico-duodenectomy?
25-30% for node-negative and and 10% for node-positive tumors
What are the major risk factors for pancreatic cancer?
Cigarette smoking, high BMI and lack of physical activity, history of chronic pancreatitis
Is there a familial aggregation and/or genetic factor w/ pancreatic cancer?
5-10% of pts have a first degree relative with the disease
What is the most common lethal genetic disease among whites?
Cystic fibrosis
What does Cystic Fibrosis (CF) result from?
A defect in Cl- channels that is caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene
What are the characteristics of CF?
Malfunction of exocrine glands, resulting in increased viscosity of mucus and increased chloride concentration in sweat and tears
What are clinical manifestations of CF?
Chronic pulmonary disease, pancreatic insufficiency, meconium ileus
Where is the CFTR channel found?
In a lot of exocrine tissues - exocrine tissues in the lungs it makes mucus - goblet cells. Exocrine cells in the pancreas are making pancreatic juice. Also, exocrine cells in the small intestine that are making mucus - again goblet cells
What happens to concentrations Cl- and Na+ inside cells when CFTR channels are missing?
Cl- cannot enter the cell and as a result neither can Na+, since it would enter to balance the electric charge
What is a way to test if you have CF?
Test sweat to see if it has a high concentration of Cl-
What is the end result of these electrolytes not being enter the cells?
The fluids get really thick and viscous - so the mucus you make in your airways is really thick (clogs up airways), sweat is thicker, pancreatic juice is thicker, all the mucus in your intestines is very thick
What is meconium ileus?
The mucus in your intestines gets really thick that it creates blockage and food and fecal matter cannot get thru
What happens to Cl- in the lungs of someone that has CF?
Cl- cannot get out of the cells, so Na+ is brought into the airway cells bringing water with it and the mucus gets really thick making it harder to breathe
