GI 122 Pancreas and Gall Bladder

Question 1

What hormones are produced in the islet cells and are they endocrine or exocrine?

Answer 1

Insulin and glucagon - endocrine

Question 2

What is the function of the acinar cells and are they exocrine or endocrine?

Answer 2

Produce digestive enzymes in an alkaline solution for neutralisation - exocrine

Question 3

Name the three different cell types of the Islets of Langherhans and the enzymes that they produce

Answer 3

alpha cells secrete glucagon
beta cells secrete insulin
delta cells secrete somatostatin

Question 4

Where does venous blood from the pancreas drain into?

Answer 4

The portal vein

Question 5

Except for the head of the pancreas, what artery supplies most of the pancreas?

Answer 5

The splenic artery - branch of the coeliac artery

Question 6

From what plexus does the pancreas receive sympathetic and parasympathetic stimulation?

Answer 6

The coeliac plexus

Question 7

What, broadly speaking, controls exocrine function?

Answer 7

It is neurohormonal: vagus nerve and hormones

Question 8

Describe the cephalic phase

Answer 8

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

Question 9

Describe the gastric phase

Answer 9

Stomach distension stimulates vagovagal reflex, protein digestion products promote release of gastrin

Question 10

What does gastrin do and where is it released from?

Answer 10

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

Question 11

What is the action of somatostatin?

Answer 11

Reduces acid secretion by parietal cells

Reduces secretin excretion

Question 12

What is secretin released in response to and what is its function?

Answer 12

Low pH in the duodenum and causes pancreas to secrete watery bicarbonate solution to neutralise the pH in the duodenum

Question 13

What is CCK release in response to and what is its function?

Answer 13

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

Question 14

Name the main aetiologies for acute pancreatitis

Answer 14

Gallstones (block ampulla of vater), alcohol (makes pancreatic secretions more viscous), pregnancy and autoimmune causes

Question 15

What is the diagnostic range for acute pancreatitis of serum amylase, when is it raised and what could a lesser increase indicate

Answer 15

> 3x the normal range raised within 24hrs of pain onset and a lesser increase could indicate cholecystitis

Question 16

How would you treat mild acute pancreatitis

Answer 16

Fluids to maintain BP/HR and urine output
02
NG tube to relieve pressure on the ileus
Analgesia

Question 17

Name the main aetiologies for chronic pancreatitis

Answer 17

Alcohol ( 80% in the developed world), malnutrition, hereditary causes, CF,

Question 18

What is the basic structure of a triglyceride?

Answer 18

Glycerol backbone and fatty acids attached by ester bonds

Question 19

What are two essential FA’s that must be gained through the diet?

Answer 19

Linoleic acid and Linolenic acid

Question 20

How do lipids enter the duodenum?

Answer 20

As emulsion droplets

Question 21

What are the 4 lipolytic enzymes that are secreted into the duodenum?

Answer 21

Lipase, collipase, phospholipase A2 and cholesterol esterase

Question 22

What does collipase do?

Answer 22

Attach to TG molecule on surface of emulsion droplet.

Anchor for lipase

Question 23

What does lipase do?

Answer 23

Hydrolyzes ester bonds to release FA’s and monoglyceride

Question 24

What does phospholipase A2 do?

Answer 24

act on phospholipid (lecithin) to produce lysolecithin and FA’s

Question 25

What does cholesterol esterase do?

Answer 25

Hydrolyzes FA's from cholesterol ester --> cholesterol

Question 26

What are lipolytic products transferred to?

Answer 26

Mixed micelles

Question 27

Name the two features of a micelle and give an example one in the blood stream?

Answer 27

Lipid core and amphipathic bile acid skin | Chylomicrons

Question 28

What are bile acids conjugated with to form bile salts? And what does this allow them to do?

Answer 28

Taurine or glycine | Allows them to be fully ionized at physiological pH

Question 29

What do bile salts do and why are they better than bile acids?

Answer 29

They are more effective detergents than bile acids, they emulsify lipids, form mixed micelles and are an excretion route for cholesterol

Question 30

Where is heme found

Answer 30

RBC's

Question 31

Where does breakdown of RBC's occur

Answer 31

Macrophages in the liver and spleen (reticuloendothelial system)

Question 32

What enzyme performs the first two cleavages of the heme molecule in its breakdown? And what does it release?

Answer 32

Microsomal heme oxygenase | Releases CO and Fe3+ --> Green pigment biliverdin

Question 33

What is biliverdin, what is it reduced by and what does it become?

Answer 33

Biliverdin is the green pigment of RBC breakdown, it is reduced by biliverdin reductase and it becomes bilirubin

Question 34

What cells does bilirubin enter? And what occurs here?

Answer 34

Hepatocytes - conjugated with glucaronic acid

Question 35

Where is the glucaronic acid removed?

Answer 35

In the intestine

Question 36

What provides the colour of urine and faeces?

Answer 36

Urobillinogen and stercobillingogen

Question 37

What are the three different types of f gallstones?

Answer 37

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

Question 38

What are the risk factors for gallstones?

Answer 38

5 F's: fair, fat, fertile, female and forty | Also drugs, crohns and diabetes

Question 39

What is a mucocoele?

Answer 39

When GB exit is blocked, bile acid is absorbed and the GB becomes distended and full of mucus

Question 40

When do you get biliary colic?

Answer 40

When gallstone is lodged in the cystic duct or common bile duct

Question 41

What are the common presentations of gallstones?

Answer 41

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

Question 42

When does empyema occur?

Answer 42

When the ducts that are obstructed become infected

Question 43

What is acute cholecystitis?

Answer 43

Inflammation due to obstruction of GB/cystic ducts

Question 44

What is obstructive jaundice?

Answer 44

Obstruction of the hepatic or common bile duct e.g. a stone or mass in pancreatic head, leading to jaundice