Physiology and Pathology: The Pancreas Flashcards
(84 cards)
1
Q
Four parts of the pancreas?
A
- Head and uncinate process
- Neck
- Body
- Tail
2
Q
________ joins ________ at the hepatopancreatic ampulla (ampulla of vater)
A
Main pancreatic duct joins the common bile duct
3
Q
Accessory pancreatic duct drains to what?
A
The minor duodenal papilla
4
Q
Is the pancreas a retro-peritoneal structure?
A
yes
5
Q
Arterial supply of pancreas head?
A
- Pancreaticoduodenal branches of the gastroduodenal artery
- Superior mesenteric artery
6
Q
Arterial supply of pancreas neck, body, tail?
A
- Branches of splenic artery (celiac trunk)
7
Q
Venous supply of the pancreas?
A
- Splenic vein
- Superior mesenteric vein
8
Q
The exocrine functions of the pancreas are carried out by what?
A
The acini
9
Q
What type of gland system is the exocrine pancreas?
A
Compound tubulo-acinar
10
Q
The compound tubulo-acinar gland system produces ______ rich fluid containing digestive enzymes
A
Bicarbonate
11
Q
Acinar cells surround _______ cells - which function to line what?
A
Centro-acinar cells - line the lumen of the acinus = beginning of intercalated ducts
12
Q
Intercalated ducts branch from the lumen of the acinus and merge into what?
A
Interlobular ducts
13
Q
General functions of acinar cells? (3)
A
- Secretion of inactive pancreatic enzymes (zymogens)
- Rich RER, lots of granules
- CCK major stimulator
14
Q
General function of centroacinar cells? (2)
A
- Secretion of bicarb-rich fluid
- Secretin major stimulator
15
Q
What two cell types secrete bicarbonate in response to secretin?
A
- Centro-acinar cells
- Intercalated duct cells
16
Q
_____ diffuses from blood in to cell to combine with water to form ______
A
CO2 + H2O => Carbonic acid
17
Q
Carbonic acid dissociates to form what?
A
HCO3- and H+
18
Q
HCO3- is actively transported into the duct and what follows?
A
Na+
19
Q
Movement of HCO3- and Na+ into the ducts creates what? Causes what?
A
Osmotic pressure causing osmosis of H2O into duct
20
Q
Three phases of pancreatic secretion?
A
- Cephalic
- Gastric
- Intestinal
21
Q
Cephalic phase stimulants?
A
Sight, smell, taste, mastication
22
Q
Cephalic regulatory pathway?
A
Vagal pathway
23
Q
Percentage of maximum enzyme secretion of cephalic phase?
A
20%
24
Q
Gastric phase stimulants?
A
Distention, Gastrin (?)
25
Cephalic regulatory pathway?
Vagal-cholinergic pathway
26
Percentage of maximum enzyme secretion of gastric phase?
10-20%
27
Intestinal phase stimulants?
Amino acids, FAs, H+ (after chyme leaves stomach)
28
Intestinal regulatory pathway?
CCK and Secretin (most), Enteropancreatic reflexes
29
Percentage of maximum enzyme secretion of intestinal phase?
50-80%
30
Regulation of pancreatic secretetion has both ______ and ______ control
Neural and hormonal
31
What phases are mostly regulated through nervous system?
Cephalic and gastric phases
32
What phase is mostly under hormonal control?
Intestinal phase
33
What is the source of secretin and what is its stimulus?
Source = S cells lining duodenum
Stim = Acid entering duodenum
34
What is the source of CCK and what is its stimulus?
Source = I cells in duodenum
Stim = Fat and aa's entering duodenum
35
What do Secretin and CCK stimulate in the pancreas?
Secretin = fluid secretion (HCO3-)
CCK = Enzyme secretion
36
What do Secretin and CCK stimulate in the gall bladder?
Secretin = nothing
CCK = contraction of GB, relaxation of sphincter of Oddi
37
The 2 secretions combine and then flow through what?
The long pancreatic duct
38
The long pancreatic duct joins _____ and releases the secretions where?
Common bile duct; releases secretions into ampulla of Vater
39
Secretions empties into the duodenum through what? What is this surrounded by?
Major duodenal papilla - surrounded by Sphincter of Oddi
40
Enzyme that through hydrolysis, cleave peptide bonds at certain amino acids?
Endopeptidase
41
Examples of endopeptidases? (4)
- Pepsin
- Trypsin
- Chymotrypsin
- Elastase
42
Enzyme that through hydrolysis, cleave peptide bonds at the carboxyterminus?
Exopeptidases
43
Example of exopeptidase?
Carboxypeptidases (A + B)
44
What do trypsin inhibitors do?
Prevent pancreatic auto-digestion
45
What are trypsin inhibitors secreted from? What does this do?
Secreted from acinar cells = prevents activation of trypsin inside secretory cell and in ducts of pancreas
46
What happens when trypsin runs out of proteins to break down in the duodenum?
Hydrolyzes itself in a form of negative feedback loop
47
What does pancreatic amylase do?
Hydrolyzes alpha 1-4 linkages in amylose (starch)
48
Enzyme activated by trypsin that digests phospholipids?
Phospholipase A2
49
What are pancreatic lipase and colipase for?
Pancreatic lipase needs fat emulsification and colipase to cleave triglycerides
50
Acute pancreatitis severity?
Ranges from life-threatening to a self-limited illness
51
Major risk factors for acute pancreatitis?
- Excessive alcohol intake
- Cholelithiasis
52
Acute pancreatitis is acute, reversible pancreatic injury associated with what?
Inflammation
53
Metabolic etiologies of acute pancreatitis? (4)
- Alcoholism
- Hyperlipoproteinemia
- Hypercalcemia
- Drugs (eg azathioprine)
54
Genetic etiologies of acute pancreatitis?
- Mutations in the cationic trypsinogen and trypsin inhibitor genes PRSS1 and SPINK1
55
Mechanical etiologies of acute pancreatitis? (3)
- Gallstones
- Trauma
- Operative injury
56
Vascular etiologies of acute pancreatitis? (3)
- Shock
- Atheroembolism
- Vasculitis
57
What is the tole of trypsinogen activation in acute pancreatitis?
Its a digestive enzyme (trypsin) capable of activating other zymogens
58
What does alcohol ingestion cause regarding acute pancreatitis? (3)
- Excessive protein in pancreatic duct
- Directly toxic to acinar cells
- Causes contraction of sphincter of Oddi
59
What does biliary tract obstruction cause regarding acute pancreatitis?
Pancreatic secretions get stuck in the ducts
60
Common factor regarding pathophysiology of acute pancreatitis>
Blockage of ducts
61
As ducts become obstructed, pressure begins to build in the interstitia causing what?
Interstitial edema and impaired blood flow
62
What do injured tissues, aeriacinar myofibroblasts and leukocytes release?
Pro-inflammatory cytokines: IL-1 beta, IL-6, TNF, platelet-activating factor, and substance P
63
Activation of complement and clotting cascade leads to what?
Impairment of blood flow
64
The systemic inflammatory response of acute pancreatitis can lead to? (4)
- Leukocytosis
- Hemolysis
- Disseminated intravascular coagulation
- Acute respiratory distress syndrome
65
Pathological features of acute pancreatitis? (5)
- Microvascular leakage = edema
- Digestion of fat
- Acute inflammation
- Proteolytic destruction of parenchyma
- Destruction of blood vessels
66
What can be seen at any stage?
Fat necrosis
67
What happens when free pancreatic lipases cleave triglycerides in the abdominal cavity?
Saponification - FAs combine with extracellular Ca2+
68
What can saponification lead to?
Hypercalcemia
69
Cardinal manifestation of acute pancreatitis?
Abdominal Pain
70
Sx in acute pancreatitis?
- Constant, intense, epigastric pain
- Anorexia, nausea, and vomiting
71
Systemic effects of severe acute pancreatitis? (3)
- Systemic inflammation
- Hemorrhage
- Fluid loss into the abdomen
72
Complications of acute pancreatitis? (5)
- Pseudocysts
- Chronic pancreatitis
- Infection
- Hemorrhage or shock
- Death
73
Inflammation of the pancreas with irreversible destruction of exocrine parenchyma, fibrosis, and, in the late stages, the destruction of endocrine parenchyma?
Chronic Pancreatitis
74
What usually causes chronic pancreatitis? (2)
- Repeated bouts of acute pancreatitis
- Long-term alcohol abuse
75
What do you tend to see in chronic pancreatitis?
Irreversible/chronic ductal obstruction by concretions = calcified plugs
76
Pathology of chronic pancreatitis? (4)
- Parenchymal fibrosis
- Reduced # and size of acini
- Variable dilation of pancreatic ducts
- Chronic inflammatory infiltrate around lobules and ducts
77
What cells are usually spared until end-stage chronic pancreatitis?
Islets of Langerhans
78
Clinical findings of chronic pancreatitis?
Repeated attacks of acute pancreatitis
79
chronic pancreatitis may be entirely silent until when?
Pancreatic insufficiency (malabsorption) and diabetes develop
80
What are localized collections of necrotic-hemorrhagic material rich in pancreatic enzymes?
Pseudocysts
81
What do pseudocysts lack?
Epithelial lining
82
When do pseudocysts usually arise?
After an episode of acute pancreatitis or in chronic pancreatitis
83
Locations of pseudocysts? (4)
- Within pancreas
- Lesser omentum
- Retro-peritoneum
- Sub-diaphragmatic (rarely)
84
What are pseudocysts formed by?
Walling off of fat necrosis with fibrous tissue
