2 C: Anatomy/Phy/Path of Pancreas Flashcards
Describe the endocrine pancreas
Production of insulin & glucagon; plasma glucose regulation
Describe the exocrine pancreas
Production of pancreatic juice
- **Source of HCO3- to neutralize gastric acid
- **Source of many digestive enzymes
What does pancreatic juice consist of ? pH?
- HCO3- and the digestive enzymes are secreted by the pancreas as pancreatic juice.
- pH= 7.6-8.2
Pancreatic juice travels from the pancreas to the duodenum via the ________________________
Main pancreatic duct
***1500 ml of pancreatic juice secreted per day
What neutralizes the gastric acid, raising the duodenal content to 6.0-7.0?
Pancreatic juice, Bile, and Intestinal juices are neutral or alkaline
What are the enzymes that are included in the pancreatic juice?
1) Pancreatic amylase
2) Pancreatic lipase
3) Colipase
4) * Trypsinogen
5) * chymotrypsinogen
6) * procarboxypeptidase (A/B)
7) * proelastase
8) ribonuclease
9) deoxyribonuclease
**these 4 are proteases (inactive until they hit the duodenum)
Proteases of the pancreatic juice are secreted as __________
inactive “proenzymes”
What is Trypsinogen converted into?
What converts it?
Trypsin
***Converted by the brush border enzyme ENTEROKINASE (also known as enteropeptidase) when the pancreatic juice enters the duodenum
What does Trypsin convert chymotrypsinogen into active ____________
chymotrypsin
What does Trypsin convert procarboxypeptidase into active ____________
carboxypeptidase
What does Trypsin convert proelastase into active ____________
elastase
How can Enterokinase deficiency occur?
As a congenital abnormality, which leads to protein malnutrition
Where do these proenzymes get converted to active forms?
In the duodenum (brush border) on epithelial cells
What can releasing trypsin in its active form lead to ?
A chain reaction of producing several active enzymes capable of digesting THE PANCREAS!
Note: **Pancreatic tissue has TRYPSIN INHIBITORS to prevent this!
Secretion of pancreatic juice is under what control?
Hormonal control
What does Secretin act on?
The pancreas to cause copies secretion of a very alkaline pancreatic juice that is rich in HCO3- and LOW in enzymes
What does CCK do?
Stimulates production of pancreatic juice rich in enzymes and LOW in HCO3-
What does the stimulation of the parasympathetic fibers with the vagus nerves do?
Causes secretion of a small amount of pancreatic juice rich in enzymes, but this influence is much less potent that CCK
What has some evidence shown about vagally-mediated conditioned reflex secretion of pancreatic juice?
Secreted In response to sight or smell of food
What is Acute Pancreatitis ?
A severe life-threatening disorder associates with the escapee of activated pancreatic enzymes into the pancreas and surrounding tissues.
If small amount of pancreatic digestive enzymes already naturally leak into circulation, how is different with acute pancreatitis?
The circulating levels of the digestive enzymes rise markedly.
What is a useful in diagnosing problems associated with inflammation and necrosis of pancreatic acinar cells?
Measurement of the plasma pancreatic amylase or pancreatic lipase
In pancreatitis what do these enzymes cause?
Fat necrosis or auto -digestion of the pancreas and produce fatty deposits in the abdominal cavity with the hemorrhage from the necrotic vessels.
What is the common cause of Pancreatitis?
Most cases result from gallstone (stones in the common bile duct) or alcohol abuse
What is believed to activate the enzymes in the pancreatic duct system?
Biliary tract obstruction due to gall stones, pancreatic duct obstruction or bilary reflux
When does Gallstone pancreatitis occur?
When a gallstone blocks the opening to the pancreas. Stone can lodge into an opening to the intestine. A pancreas duct shares this opening; when it is blocked, the pancreas becomes inflamed.
What is known to be a potent stimulator of pancreatic secretions ?
Alcohol
*** Also known to cause contraction of the sphincter of Oddi of the pancreatic duct
What is Acute Pancreatitis also associated with?
Hyperlipidemia, hyperparathyrodism, infections (viral), abdominal & surgical trauma, and drugs such as steroids and thiazide diuretics.
What is the most common initial symptom of Pancreatitis?
Severe epigastric and abdominal pain that radiates the back
When is the pain aggravated ?
When the person is lying supine; It is less severe when the person is sitting and leaning forward.
***Abdominal distention accompanied by hypoactive bowel sounds in common.
What is an important disturbance related to acute pancreatitis ?
The loss of a large volume of fluid into the abdominal cavity
***Tachycardia, hypotension, cool and clammy skin, and fever often are evident.
Why do signs of hypocalcemia develop?
Develop as a result of the precipitation of serum calcium in areas of the fat necrosis.
What appears after the first 24 hours because of biliary obstruction ?
Mild jaundice
What does pancreatic cancer refer to?
A ductal adenocarcinoma of the pancreas (including its subtypes)
More than 95% of malignant neoplasms of the pancreas ares from what?>
The exocrine elements and are refereed to as exocrine pancreatic cancers
What is the most common presenting symptoms in patients with exocrine pancreatic cancer?
Pain, jaundice, and weight loss.
Approx. 60-70% exocrine pancreatic cancers are localized where?
To the head of the pancreas
Approx. (the rest), 20-25% exocrine pancreatic cancers are localized where?
In the body/tail and the remainder involve the whole organ.
Which tumors present more often with jaundice, steatorrhea, and weight loss?
Pancreatic head tumors (compared to tumors of the body and tail of the gland)
What is the only potentially curative treatment for exocrine pancreatic cancers?
Surgical resection (pancreatectomy )
***Because of late presentation only 15-20% of patients are candidates for pancreatectomy
What is the five-year survival following pancreaticoduodenectomy ?
25-30% for node-negative and 10% for node-positive tumors
Whgat is the major risk factors for pancreatic cancer?
1) Cigarette smoking
2) High body mass and lack of physical activity
3) History of chronic pancreatitis
Why is a role for familial aggregation and/or genetic factors suggested ?
Because 5-10 % of patients w/ pancreatic cancer have a 1st degree relative with the disease
What is the most common lethal genetic disease among white?
Cystic Fibrosis (CF)
What does CF result from?
From a defect in the Cl- channels that is caused by a mutation in the cystic fibrosis transmembrane conductance regulator gene (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?
1) Chronic pulmonary disease
2) Pancreatic insufficiency
3) Meconium ileus
What is an important diagnostic procedure?
Sweat test.
