pancreas disorders Flashcards
1
Q
digestive functions of the pancreas
A
produce digestive enzymes
2
Q
hormonal functions of the pancreas
A
islets of langerhans produce insulin that controls blood sugar levels
3
Q
what is the endocrine pancreas made of
A
islets of langerhans
4
Q
what is the exoocrine pancreas made of
A
acini cells
5
Q
what do acini cells do
A
secrete pancreatic juice in the duodenum through pancreatic ducts
6
Q
what is pancreatic juice important for
A
digestion absorption; pancreatic insufficiency and fatty stools
7
Q
what does dysfunction of the pancreas cause
A
DM
8
Q
what is islets of langerhan cells produce
A
insulin
9
Q
4 parts of pancreas?
A
head, neck, body, tail
10
Q
where is the ucinate process/curvature of the duodenum located?
A
head of pancreas
11
Q
what is the exocrine pancreas drained by?
A
duct of wirsung
12
Q
tell me about the duct of wirsung
A
main pancreatic duct that runs the length of the gland and is 3-4mm in diameter
13
Q
where does the main pancreatic duct enter the duodenum
A
duodenal papilla
14
Q
where does the main pancreatic duct end?
A
ampulla of vater
15
Q
what does the sphincter of oddi surround
A
common bile duct and main pancreatic duct
16
Q
what 2 ducts join together to form a common channel before ending at the ampulla of vater
A
main pancreatic duct and common bile duct
17
Q
what is the duct of santorini?
A
separate accessory pancreatic duct pany ppl have
18
Q
what are acinar cells
A
pyramidal epithelial cells arranged in rows; their apexes join to form the lumen of the acinus
19
Q
where are zymogen granules found? what are they?
A
acinar cells; inactive enzymes
20
Q
how are zymogens released
A
exocytosis from apexes of the acinar cells into the lumen
21
Q
when are there more zymogen granules in the acinar cells? less?
A
more: fasting
less: after a meal
22
Q
what enzymes are secreted by the acinar cells in their active form?
A
lipase, amylase, deoxyribonuclease, ribinuclease
23
Q
what enzymes are secreted by the acinar cells as zymogens?
A
trypsinogen, chymotrypsin, prolastase, procarboxypeptidase, phospholipase 2A
24
Q
where are zymogens activated?
A
lumen of proximal intestine
25
what does activation of zymogens in acinar cells lead to
acute pancreatitis and pancreatic autodigestion
26
what happens when pancreatic juice enters the duodenum
trypsinogen is converted to trypsin
27
what facilitates the conversion of trypsinogen to trypsin? where is this found?
enteropeptidase/ enterokinase; on intestinal brush border
28
why is trypsin important?
converts remaining zymogens to active enzymes (like a cascade)
29
if trypsinogen is activated in the pancreas, what are the two protective mechanisms?
pancreatic secretory trypsin inhibitor (PSTI) and trypsin autolysis
30
acute pancreatitis is a clinical syndrome resulting from what?
acute inflammation and autodigestion of pancreas and peripancreatic tissues
31
what are the clinical manifestations of acute pancreatitis?
acute upper abdominal pain, nausea, vomiting, fever
32
what are the 2 most common causes of acute pancreatitis?
biliary tract disease and alcohol trauma
33
what is common in all cases of acute pancreatitis?
activated proteolytic enzymes escape from ducts which cause local tissue injury, inflammation, necrosis, and infection in some cases
34
when does alcohol induced pancreatitis occur?
after a heavy episode of drinking
35
what is the mechanism of alcohol induced pancreatitis?
unclear how alcohol damages the gland
36
what is the metabolite of alcohol
acetaldehyde
37
what disease may have a direct toxic effect on the pancreatic acinar cells
alcohol induced pancreatitis
38
what may alcohol induced pancreatitis lead do?
intracellular trypsin activation and inflammation of the sphincter of oddi
39
what disease is associated with deficiences in zinc or selenium
alcohol induced pancreatitis and chronic pancreatitis
40
what occurs in biliary tract disease
gallstones or biliary sludges become lodged at ampulla of vater
41
what do gallstones or biliary sludges becomming lodged at ampulla of vater cause
obstruction of common bile duct and main pancreatic duct
42
is biliary tract disease more common in men or women? what about gallstones?
both women
43
key pathologic finding in acute pancreatitis?
fat necrosis
44
what is chronic pancreatitis?
relapsing disorder with severe abdominal pain, exocrine or endocrine pancreatic insufficiency, duct abnormalities, pancreatic calcifications
45
what is the major cause of chronic pancreatitis?
chronic alcoholism
46
what do deficiencies in zinc and selenium inhibit in chronic pancreatitis
quenching of O2 free radicals
47
what can long term obstruction of the pancreatic duct cause
chronic pancreatitis
48
what is the key panthological finding in chronic and acute pancreatitis
peripancreatic and intrapancreatic fat necrosis
49
what is chronic pancreatitis characterized by?
scarring and shrinkage of the pancreas
50
what does scarring and shrinkage of the pancreas result from
fibrosis, atrophy of acini, and stenosis/dilation of ductules
51
what part of the pancreas is involved in chronic pancreatitis?
usually the whole gland, but it's localized to the head and body in 1/3 of cases
52
what are ductules and ducts often filled with in chronic pancreatitis?
calculi (ductal stones)
53
why is the pancreas hard in chronic pancreatitis?
sclerosis and calcification
54
why might someone need a biopsy of the pancreas
differentiate chronic pancreatitis from pancreatic carcinoma
55
what does chronic pancreatitis look like microscopically?
loss of acini, dilation of ductules, fibrosis, lymphocytes
56
what is preserved in chronic pancreatitis?
islets of langerhans
57
what are the clinical manifestations of chronic pancreatitis?
maldigestion and impaired fat digestion
58
what enzyme is essential for fat digestion
pancreatic lipase
59
what can absence of pancreatic lipase lead to?
steatorrhea which is a greasy, bulky, lightly colored stool
60
why do ppl with pancreatic insufficiency rarely present with carb and protein maldigestion?
other enzymes in gastric and intestinal juice compensate for loss of amylase and trypsin
61
what is pancreatic insufficiency?
syndrome of maldigestion which results from disorders interfering with effective pancreatic enzyme activity
62
where are islets of langerhan located?
embedded in pancreatic exocrine tissues
63
are islets of langerhan cells vascularized
yes
64
what are the 4 major islet cell types
beta, alpha, delta, and PP
65
what is the predominant cell in the islet
beta
66
what do beta islet cells secrete?
insulin
67
what are alpha islet cells?
glucagon secreting cells
68
what are delta islet cells?
somatostatin secreting cells
69
what are PP islet cells?
pancreatic polyeptide secreting cells
70
where are PP cells located?
posterior lobe of the head of the pancreas
71
more the 70% of the insulin secreting cells must be lost/damaged before dysfunction occurs in what?
endocrine pancreas
72
what supplies each islet with nutrients
one major arteriole
73
where does blood from the islets drain into?
hepatic portal vein
74
what is the major site of action of glucagon and insulin
liver
75
what are islets innervated directly by?
parasympathetic and sympathetic NS
76
what are islets innervated indirectly by?
stimulation of catecholamine release by the adrenal medulla
77
what plays a key role in glucose homeostasis during stress
catecholamine release by the adrenal medulla
78
circulator half life of insulin?
3-5 min
79
where is insulin catabolized
liver and kidney
80
what is the most potent stimulator of insulin
glucose
81
what is glucose enhanced by?
several enteric proteins such as glucagon like peptide 1 (GLP-1)
82
what is glucose inhibited by?
catecholamines and somatostatins
83
what is the mechanism of insulin?
it exerts its effects by binding to insulin receptors on the surface of target cells
84
what are the target cells of insulin
liver, muscle, fat and ovaries
85
what is the role of insulin in metabolism
fuel homeostasis, promote fuel storage, promote formation of precursors for fatty acid synthesis, stimulate lipogenesis, inhibit hepatic glucose output
86
what is anabolism
fuel storage
87
catabolism?
breakdown and release of fuel
88
how does insulin promote fuel storage in liver?
stimulating glycogen synthesis and storage
89
how does insulin promote formation of precursors for fatty acid synthesis?
stimulating glycolysis
90
how does insulin stimulate lipogenesis?
VLDL synthesis is increased
91
how does insulin inhibit hepatic glucose output?
inhiting gluconeogenesis and glycogenolysis
92
what inhibits fatty acid oxidation and production of ketone bodies
insulin
93
where are ketones made
liver
94
where and when are ketones used as fuel
in the brain when glucose isnt available
95
what s DM
heterogeneous disorder defined by presence of hyperglycemia
96
what can hyperglycemia be due to
dec in insulin secretion by pancreatic cells, dec response to insulin by target tissues, or increase in counterregulatory hormones that oppose effects of insulin
97
what was formerly known asIDDM and juvelile diabetes
DM type 1
98
what is DM type 1 characterized by
autoimmune destruction of pancreatic islet cells that results in severe insulin deficiency
99
why does DM type 1 mainly affect
ppl younger than 30
100
where is there a bimodal incidence peak in DM type 1
5-7 y/o and puberty
101
who is DM type 1 more common in
males
102
what do patients with DM type 1 present with
polyuria, polydipsia, and weight loss with high serum glucose levels
103
what is diabetic ketoacidosis
when ketone bodies are increased because of lack of insulin in DM type 1
104
is DM type 1 autoimmune
yes
105
what isDM type 1 caused by
destruction of pancreatic beta cells which makes autoreactive T lymphocytes
106
what is the early disease of DM type 1 marked by
lymphocytic infiltrates
107
what surrounds the necrotic beta cells in DM type 1
CD4 T cells and cytotoxic CD8 T cells
108
what is an important diagnostic criteria of DM type 1 ?
autoantibodies are present but are not responsible for destruction
109
50% of newly diagnosed DM type 1 patients have increased...
islet cell autoantibodies (ICA) and insulin autoantibody (IAA)
110
can screening be used to identify majority of DM type 1 ppl?
no
111
what alleles have the strongest influence for DM type 1 risk?
class II HLA-DR and HLA-DQ loci
112
what environmental factors may lead to DM type 1 ?
viral infections such as exposure to rubella
113
molecular mimicry is associated with the etiology of what disease
DM type 1
114
who does DM type 2 occur most commonly in
adults, native americans, mexican americans, and african americans
115
is there a stronger genetic component for DM type 1 or 2
2
116
this disorder is associated with an increased resistance to the effects of insulin at its sites of action and decreased insulin secretion by the pancreas
DM type 2
117
what can ameliorate or even terminate DM type 2
weight loss in obese or overweight ppl
118
what 2 metabolic defects are responsible for hyperglycemia in DM type 2
1. target tissue resistance to insulin
| 2. inadequate pancreatic cell insulin secretion
119
can a genetic test identify ppl at risk for type 2 diabetes
no
120
what is the debate about in DM type 2
whether the primary lesion is insulin resistance or defective cell insulin secretion
121
what is a key factor in the link btwn obesity and DM type 2
insulin resistance
122
what is the primary source of mediators of insulin resistance
central/abdomoinal adiposity
123
how does central/abdomoinal adiposity increase insulin resistance
lipotoxicity, adipokines, and hormones
124
what are adipokines
dysregulated secretion of cytokines made in fat tissue
125
what are the toxic effects of excess free fatty acids
dec skeletal muscle insulin sensitivity
126
what does leptin do
controls satiety and enhances insulin sensitivity
127
do most ppl with type 2 DM develop diabetes
no
128
what kinda of disorders is DM a secondary disease?
pancreatitis, cushings syndrome, genetic beta cell defects, drugs like HIV protease inhibitors
129
who does gestational DM occur in?
pregnant women in their 2nd or 3rd trimester
130
what is gestational DM caused by
increasing levels of the hormones progesterone, cortisol, and prolactin
131
how is gestational DM diagnosed
oral glucose tests
132
when is gestational DM resolved
parturition, but 50% of these ppl develop type 2 DM later in life
