Pancreas + Gallbladder Flashcards
What are the 3 main causes of pancreatitis?
Gall stones
Alcohol (either damages acinar cells or sphincter of oddy)
Autoimmune
What is the main drug which causes a risk of pancreatitis?
Azothioprim (for Crohns)
Name a cause of jaundice which is painless and presents with a palpable mass in RUQ?
Cancer of head of pancreas
Which enzymes are raised in patients with pancreatitis?
Amylase and Lipase
What is the peritoneal covering of the pancreas?
It is retroperitoneal (except for tail)
What are the four parts of the pancreas?
Tail
Body
Head
Uncinate process
Which arteries supply the pancreas?
Branches of splenic art
Sup mesenteric art
Common hepatic art
Which veins drain the pancreas?
Pancreatic duodenal vein
from hepatic portal vein
What type of gland is the pancreas?
Mainly exocrine
A compound tuberoalveolar gland which branches from main pancreatic duct going into lobules then into individual pancreatic acini
Pancreatic acini are lined with what tupe of epithelium?
Simple cuboidal
What are islets of langerhans and how much of the pancreas do they make up?
Endocrine cells which secrete insulin and glucagon into the blood stream
Make up less than 1% of pancreatic cells
What are the exocrine cells of the pancreas?
Acinar cells and epithelial cells of the ducts
Secrete pancreatic juice (an alkaline mixture of water, enzymes and ions)
Which exocrine pancreatic cells are responsible for secreting which components?
Acinar cells- Enzymes
Epithelial (duct) cells (aka centroacinar)- Water and ions
Where does the gallbladder sit?
Just inf to liver in a fossa between two liver lobes (Right and quadrate lobes)
Where does the liver initially secrete bile to and how much is produced per day?
Into bile canaliculi
Done continuously around 1L per day
Where does bile travel on it’s way from the liver to the gallbladder?
Bile canaliculi > bile ductules > R+L hepatic duct > common hepatic duct > cystic duct > gallbladder
What is bile used for?
Breaking down lipids in the lumen of the duodenum by emulsification
What are the three regions of the gallbladder?
Fundus (most superior)
Body
Neck (most inferior)
The common bile duct is formed from which two ducts?
Cystic duct
Common hepatic duct
CCK is release from where and what does it do to the gallbladder?
Released by I-cells of duodenum when chyme enters
Stimulates gall bladder contraction, hepatopancreatic sphincter dilation
Which artery/ vein and nerve supply the gall bladder and billary tree?
Art: Cystic artery (from R hepatic)
Vein: Cystic vein (from hepatic portal vein)
Nerve: Celiac ganglia (from thoracic splanchnic)
What 4 things are secreated by pancreatic acinar cells?
Pancreatic alpha amylase (Carbohydrase, breaks starch) Pancreatic lipase (Lipids to FA's) Nucleases (break down DNA and RNA) Proteolytic enzymes (proteases and peptidases)
What is the main enzyme secreted from pancreatic acinar cells?
Proteolytic enzymes are 70% of secretions
Proteases (large protein > small protein)
Peptideass (small protein > AA’s)
Chyme and a low pH in the duodenum stimulates X cells to release Y, this has the effect of Z.
X= S cells Y= Secretin Z= Increases watery buffer (HCO3-) solution secretion from pancreatic centroacinar cells
What effect does CCK have on the pancreas?
Causes release of digestive enzymes from the acinar cells
What nerve is active in the cephalic digestion phase and what effect does this have? Why is this important?
Vagal stimulation causes release of digestive enzymes from pancreatic acinar cells. Important as enzymes secretion needs head start as takes longer than buffer secretion
Release of bicarbonate ions from centroacinar cells is stimulated by which hormone?
Secretin
Release of enzymes from basophillic acinar cells is stimulated by which hormone?
CCK
What effects do SNS and PNS stimulation have on levels of secretion in the pancreas?
PNS = Increased secretion SNS= Decreased secretion
What are the main causes of pancreatitis?
1- Gallstones 2- Alcohol 3- Trauma
Drugs (steroids/ oestrogens)/ hyperlipidaemia/ infection/ tumours
What is the pathophysiology of acute pancreatitis?
Raised intracellular Ca2+ causes conversion of trypsinogen to trypsin and early activation of enzymes = cellular necrosis
Impairs degradation of trypsin by chymotrypsin C
What is responsible for degradation of trypsin?
Chymotrypsin C
What is the pathophysiology of acute pancreatitis with alcohol as the causative agent?
Alcohol increases calcium levels in acinar cells
What is the pathophysiology of acute pancreatitis with gallstones as the cause?
Occlusion of drainage at ampulla leads to ductal hypertension
This increases cystolic free ionized Ca2+
What treatment would be given to someone with acute pancreatitis?
Analgesia
Nasogastric suction (reduce vomiting)
Fluids and treat cause
What is the M/F ratio, main cause and most common presentation age of chronic pancreatitis?
M4:1F
70% causes by alcohol
Most common age 45-54
What is the pathophysiology of chronic pancreatits?
Precipitation of protein in ducts (caused by alcohol) leads to ductal hypertension and raised Ca2+ levels. This increases trypsin activation and thus cellular necrosis and eventually fibrosis
Which tissues are affected first in chronic pancreatitis, endocrine or exocrine?
Exocrine
What are some of the RF’s and causes of chronic pancreatitis?
Alcohol/ smoking/ autoimmune/ genetics/ trauma/ blocked ducts/ radiotherapy
Name two genes implicated in chronic pancreatitis?
PRSS1 and SPINK-1
What diagnostic tests can be used for chronic pancreatitis, additional to those for acute?
Fecal elastase
Image for calcification
Secretin stimulation test (+ve if >60% enzyme insufficiency)
What is the treatment for chronic pancreatitis?
Reduce dietary fat/ alcohol and smoking cessation
Analegics (NSAID/ tramadol/ TCA)
Pancreatin and PPI
What is the 10yr survival rate for chronic pancreatitis?
70%
What is a pancreatic pseudocyst?
75% of all pancreatic masses
An accumulation of pancreatic enzymes/ blood and necrotic tissue- surrounded by granulation tissue
(True cysts are surrounded by epithelium)
1 unit of alcohol is equal to what?
1oml pure ethanol
8g of ethanol
Half a pint/ a small glass of wine
How is alcohol removed from the body?
10% excreted in breath
90% metabolised in the liver
How is alcohol metabolised?
Ethanol > Acetaldehyde (Enzyme : Alcohol dehydrogenase)
Acetaldehyde > Acetic acid (Enzyme: Aldelydehyrdogenase)
- Both oxidise and reduce (NAD+ to NADH)
What happens to the livers of alcoholics in relation to fat and why?
Reduction of NAD+ is also needed for fatty acid oxidation so alcoholics have a fat accumulation in their liver
(Hepatitis > fibrosis > cirrhosis)
What is alcohol dehydrogenase?
An enzyme which starts working in the stomach and continues to the liver, it converts ethanol to acetaldehyde NB: women/ Asians have lower levels so can’t tolerate as much alcohol
How fast can we metabolise alcohol?
1unit per hour
What molecule is responsible for causing the ‘hangover’ effect?
Acetaldehyde
(normally only a small amount escapes the liver however when excess consumption of ethanol the circulating volume increases)
Name two serum tests which can be done to indicate alcoholism?
Gamma-glutamyl transpeptidase
MCV
Both indicate excess alcohol intake when raised
What are the negative effects of alcohol?
Stimulant at low levels, depressant (especially of cardio/ resp) at high levels
Neurotoxic (seizurers/ motor impairment)
What is Wenicke-Korsakoff syndrome and what is it associated with?
Low vitB1 (thiamine) Associated with alcohol consumption
What effects does ethanol have on blood vessels in the skin?
Cutaneous vasodilation
warm feeling but heat actually lost
Name 3 thinks which chronic ethanol consumption can lead to?
Immunosupression (inc cancer/ infection risk)
Impotence
Feminisation (in M)
What equation is used to calculate the number of units?
ABV x Vol (ml) /1000 = UNITS
Why could chronic alcohol consumption lead to pneumonia?
CNS depression increases risk of aspiration pneumonia
What is one of the reasons excess alcohol causes neurotoxicity?
Thiamine (vitB1) deficiency
Where is alcohol dehydrogenase mainly found?
Hepatocytes
What is the best treatment for alcohol dependance?
Benzodiazepines
Thiamine
What is the most abundant pancreatic enzyme?
Trypsin
What is the role of phospholipase?
Splits FA’s from phospholipids
Trypsinogen is activated by what?
Enterokinase
release when chyme contacts intestinal mucosa
How do trypsin secreting cells stop themselves being broken down?
Cells that secrete proteolytic enzymes simultaneously secrete trypsin inhibitor. It prevents activation of trypsin both inside the secretory cells and in the acini and ducts of the pancreas.
Name two substances that can stimulate the acinar cells of the pancreas to produce digestive enzymes?
CCK
ACh from nerves
During which phase does most pancreatic secretion happen?
Cephalic = 20% mainly enzymes Gastric= 10% Intestinal= 70% due to more CCK/secretin
In what form is secretin released and how is it activated?
Released as prosecretin by S cells
Activated when pH goes lower than 4.5
What two substances are excreted in bile?
Cholesterol and bilirubin
What % of released bile salts are reabsorbed?
95%
Which pancreatic cells release ghrelin?
E-cells
