GI 122 Pancreas and Gall Bladder Flashcards
What hormones are produced in the islet cells and are they endocrine or exocrine?
Insulin and glucagon - endocrine
What is the function of the acinar cells and are they exocrine or endocrine?
Produce digestive enzymes in an alkaline solution for neutralisation - exocrine
Name the three different cell types of the Islets of Langherhans and the enzymes that they produce
alpha cells secrete glucagon
beta cells secrete insulin
delta cells secrete somatostatin
Where does venous blood from the pancreas drain into?
The portal vein
Except for the head of the pancreas, what artery supplies most of the pancreas?
The splenic artery - branch of the coeliac artery
From what plexus does the pancreas receive sympathetic and parasympathetic stimulation?
The coeliac plexus
What, broadly speaking, controls exocrine function?
It is neurohormonal: vagus nerve and hormones
Describe the cephalic phase
The sight, taste and smell of food stimulates the hypothalamus via the vagus nerve and thus stimulates up to 40% of secretion by the pancreas and salivary glands
Describe the gastric phase
Stomach distension stimulates vagovagal reflex, protein digestion products promote release of gastrin
What does gastrin do and where is it released from?
Gastrin is released from G-cells in the antrum and stimulates the Parietal cells to produce acid (HCl)
Has wide range of actions including stimulating release of pepsinogen from chief cells and stimulating pancreatic and gallbladder contraction
What is the action of somatostatin?
Reduces acid secretion by parietal cells
Reduces secretin excretion
What is secretin released in response to and what is its function?
Low pH in the duodenum and causes pancreas to secrete watery bicarbonate solution to neutralise the pH in the duodenum
What is CCK release in response to and what is its function?
Released in response to lipids and proteins in the duodenum and causes gallbladder contraction/sphincter of oddi relaxation and the acinar cells to secrete enzymes
Name the main aetiologies for acute pancreatitis
Gallstones (block ampulla of vater), alcohol (makes pancreatic secretions more viscous), pregnancy and autoimmune causes
What is the diagnostic range for acute pancreatitis of serum amylase, when is it raised and what could a lesser increase indicate
> 3x the normal range raised within 24hrs of pain onset and a lesser increase could indicate cholecystitis
How would you treat mild acute pancreatitis
Fluids to maintain BP/HR and urine output
02
NG tube to relieve pressure on the ileus
Analgesia
Name the main aetiologies for chronic pancreatitis
Alcohol ( 80% in the developed world), malnutrition, hereditary causes, CF,
What is the basic structure of a triglyceride?
Glycerol backbone and fatty acids attached by ester bonds
What are two essential FA’s that must be gained through the diet?
Linoleic acid and Linolenic acid
How do lipids enter the duodenum?
As emulsion droplets
What are the 4 lipolytic enzymes that are secreted into the duodenum?
Lipase, collipase, phospholipase A2 and cholesterol esterase
What does collipase do?
Attach to TG molecule on surface of emulsion droplet.
Anchor for lipase
What does lipase do?
Hydrolyzes ester bonds to release FA’s and monoglyceride
What does phospholipase A2 do?
act on phospholipid (lecithin) to produce lysolecithin and FA’s
What does cholesterol esterase do?
Hydrolyzes FA’s from cholesterol ester –> cholesterol
What are lipolytic products transferred to?
Mixed micelles
Name the two features of a micelle and give an example one in the blood stream?
Lipid core and amphipathic bile acid skin
Chylomicrons
What are bile acids conjugated with to form bile salts? And what does this allow them to do?
Taurine or glycine
Allows them to be fully ionized at physiological pH
What do bile salts do and why are they better than bile acids?
They are more effective detergents than bile acids, they emulsify lipids, form mixed micelles and are an excretion route for cholesterol
Where is heme found
RBC’s
Where does breakdown of RBC’s occur
Macrophages in the liver and spleen (reticuloendothelial system)
What enzyme performs the first two cleavages of the heme molecule in its breakdown? And what does it release?
Microsomal heme oxygenase
Releases CO and Fe3+ –> Green pigment biliverdin
What is biliverdin, what is it reduced by and what does it become?
Biliverdin is the green pigment of RBC breakdown, it is reduced by biliverdin reductase and it becomes bilirubin
What cells does bilirubin enter? And what occurs here?
Hepatocytes - conjugated with glucaronic acid
Where is the glucaronic acid removed?
In the intestine
What provides the colour of urine and faeces?
Urobillinogen and stercobillingogen
What are the three different types of f gallstones?
Cholesterol stones: cholesterol supersaturation and reduced bile salts
Black pigment stones: Calcium billirubinate - assoc. with haemolytic disease
Brown pigment stones: calcium/FA salts + calcium billirubinate layers - bile stasis/infection
What are the risk factors for gallstones?
5 F’s: fair, fat, fertile, female and forty
Also drugs, crohns and diabetes
What is a mucocoele?
When GB exit is blocked, bile acid is absorbed and the GB becomes distended and full of mucus
When do you get biliary colic?
When gallstone is lodged in the cystic duct or common bile duct
What are the common presentations of gallstones?
RUQ pain that is constant and crescendoing, radiates to shoulder and subscap and precipitated by fatty food
Restless, nausea and vomiting
Guarding and tenderness (poss +ve murphys sign)
Fever, high inflammatory markers - CRP and ESR
When does empyema occur?
When the ducts that are obstructed become infected
What is acute cholecystitis?
Inflammation due to obstruction of GB/cystic ducts
What is obstructive jaundice?
Obstruction of the hepatic or common bile duct e.g. a stone or mass in pancreatic head, leading to jaundice
