PBL 3

Question 1

what organ does the pancreas lie deep to?

Answer 1

deep to the stomach

Question 2

what parts of the pancreas are retroperitoneal?

Answer 2

All of pancreas is retroperitoneal except for its tail.

Question 3

what 5 parts is the pancreas composed of?

Answer 3

o	Uncinate process
o	Head – lies within the C shaped concavity of the duodenum 
o	Neck
o	Body
o	Tail

Question 4

describe the uncinate process

Answer 4

Is a hook-like projection that arises from the lower part of the head. It extends medially to lie beneath the body of the pancreas

Question 5

what do the acini (berry-like cluster of cells ) drain into?

Answer 5

drain into the centrally running main pancreatic duct.

Question 6

what is the ampulla of vater?

Answer 6

sac like enlargement (of a duct) formed by union of the pancreatic duct and the common bile duct

Question 7

where does the ampulla of vater open into the duodenum?

Answer 7

at the major duodenal papilla in the descending part of the duodenum

Question 8

what surrounds the ampulla of vater?

Answer 8

the sphincter of Oddi - this is a collection of smooth muscle which controls the entry of secretions into duodenum.

Question 9

what is minor duodenal papilla?

Answer 9

this is the opening of the accessory pancreatic duct into the descending second section of the duodenum.

Question 10

what is the accessory pancreatic duct also called? does everyone have one?

Answer 10

duct of Santorini

no, only found in around 10% of people

Question 11

what percentage of the pancreas is made up of exocrine function

Answer 11

Approximately 99% of the specialized cells of the pancreas

Question 12

what are acinar cells? what shape are they and is found abundantly in them?

Answer 12

these are the secretory exocrine cells of the pancreas

they are pyramidal shaped cells, with abundant rough ER.

Question 13

what are acini and what type of epithelium are they lined with?

Answer 13

acini are berry-like clusters of acinar cells that are lined with simple cuboidal epithelium.

Question 14

what is the function of acinar cells?

Answer 14

to produce digestive enzymes. They travel down the pancreatic duct into the bile duct and are activated when they enter the duodenum.

Question 15

what are ductal cells? what is their function? what stimulates them?

Answer 15

cells that line the pancreatic duct
They are responsible for secreting bicarbonate ions
They are stimulated by the hormone secretin

Question 16

what is the endocrine portion of the pancreas known as?

Answer 16

the Islet of Langerhans

Question 17

what cells are found in the Islet of Langerhans and what is their role?

Answer 17

Alpha cells – secrete glucagon
Beta cells – secrete insulin
Delta cells – secrete somatostatin

Question 18

what is the arterial supply of the pancreas?

Answer 18

pancreatic branches of the splenic artery

Question 19

what is the additional arterial supply to the head of the pancreas?

Answer 19

superior and inferior pancreaticoduodenal arteries

Question 20

what is the origin of the superior and inferior pancreaticoduodenal arteries?

Answer 20

Superior = branch of gastroduodenal artery. Inferior = branch of Superior mesenteric artery.

Question 21

what is the venous drainage of the pancreas?

Answer 21

Mainly splenic vein

Question 22

what does the splenic vein merge with?

Answer 22

merges with the Superior mesenteric branches of the hepatic portal vein

Question 23

what is the role of the small intestine?

Answer 23

It is the primary site of digestion and absorption of nutrients

Question 24

describe features of the duodenum

Answer 24

primary site of chemical digestions using enzymes
Shortest part of SI (20 cm)
Contains Brunner’s glands which secrete alkali secretions

Question 25

describe features of the jejunum

Answer 25

absorption of carbohydrates and proteins | has longer villi

Question 26

describe role of ileum

Answer 26

absorbs vitamin B12, bile salts and other unabsorbed products of digestion

Question 27

what are the 3 features which increase the surface area of the small intestine?

Answer 27

presence of circular folds (plicae circulares), villi and microvilli.

Question 28

what are plicae circulares?

Answer 28

circular folds of a mucous membrane that form ridges and project into the lumen of the small intestine (do not lose their elasticity when the intestine is distended)

Question 29

what are microvilli covered in?

Answer 29

a fuzzy coat known as the brush border which contains many digestive enzymes

Question 30

what is found between the grooves of intestinal villi?

Answer 30

intestinal glands aka Crypts of Lieberkühn

Question 31

what types of cells are found in the Crypts of Lieberkühn?

Answer 31

``` o Enterocytes/Absorptive cells o Goblet cells o Enteroendocrine cells o Paneth cells o Stem cells ```

Question 32

what hormones are secreted by Enteroendocrine cells?

Answer 32

Secretin, cholecystokinin (CCK), gastric inhibitory protein (GIP), motilin

Question 33

what is the role of paneth cells? how are they identified histologically?

Answer 33

They have a role in the gut’s defence. They secrete the enzyme lysozyme, which lyses bacteria and ruptures their cell walls. They appear spotted and eosinophilic

Question 34

what is the role of stem cells in the Crypt of Lieberkühn?

Answer 34

they are undifferentiated columnar epithelial cells which produce absorptive and goblet cells.

Question 35

what type of epithelial cells are goblet and enterocytes/absorptive cells?

Answer 35

simple columnar epithelial cells

Question 36

what is the role of enterocytes/absorptive cells?

Answer 36

responsible for the uptake of nutrients and produce digestive enzymes in the small intestine

Question 37

what is the role of goblet cells?

Answer 37

They synthesise alkaline mucus to provide lubrication and prevent digestive enzymes from eroding the cell walls.

Question 38

what is the arterial supply to the duodenum?

Answer 38

Proximal to the major duodenal papilla: supplied by the gastroduodenal artery which is a branch of the coeliac trunk Distal to MDP and to the end of the duodenum: supplied by pancreatic duodenal artery

Question 39

what is the arterial supply to the jejunum and ileum?

Answer 39

supplied by superior mesenteric artery and anastomoses arcades

Question 40

what is the venous drainage of the small intestine?

Answer 40

the superior mesenteric vein

Question 41

describe processes involved in meal-related motility in the small intestine

Answer 41

* Segmentation (mixing movements) – non-synchronised contractions of the circular smooth muscle in local segments. * Peristaltic waves – movement of chyme through the intestinal lumen. Arises from duodenal bulb which generates its own BER of about 12/min. Involves the contraction of the longitudinal muscle layer while the inner muscle layer in an adjacent region is relaxed. * Pendular contractions * Villus movements – contraction of the muscularis mucosae, micro mixing at the surface of the mucosa

Question 42

what digestive enzymes are secreted as zymogens?

Answer 42

``` o Trypsinogen o Chymotrypsinogen o Carboxypeptidase o Elastase o Phospholipase ```

Question 43

what activates Trypsinogen?

Answer 43

is activated via the duodenal enzyme enterokinase into its active form trypsin.

Question 44

what activates Chymotrypsinogen ?

Answer 44

activated by either duodenal enterokinase or trypsin into its active form (chymotrypsin)

Question 45

what digestive enzymes are secreted in active forms?

Answer 45

o Pancreatic lipase o Nucleases (ribonucleases, deoxyribonucleases) o Pancreatic amylase

Question 46

what is the role of pancreatic lipase?

Answer 46

degrades triglycerides into 2 fatty acids and a monoglyceride

Question 47

what is the role of Nucleases?

Answer 47

split nucleases into nucleotides

Question 48

describe the protein digestion that occurs in the small intestine?

Answer 48

o Proteolytic enzymes, including trypsin and chymotrypsin, are secreted by the pancreas and cleave proteins into smaller peptides. o Carboxypeptidase, which is a pancreatic brush border enzyme, takes off terminal amino acid from protein o Aminopeptidase and dipeptidase free the final amino acid products

Question 49

describe the lipid digestion that occurs in the small intestine?

Answer 49

They are degraded into fatty acids and glycerol.  Pancreatic lipase breaks down the triglycerides into free fatty acids and monoglycerides. It works with the help of the bile salts secreted by the liver and the gall bladder.  Bile salts attach to triglycerides to help emulsify them and aid access by pancreatic lipase.

Question 50

describe the carbohydrate digestion that occurs in the small intestine

Answer 50

Pancreatic amylase breaks down some polysaccharides into disaccharides. The enterocytes (cells of the intestinal lining) which cover the intestinal microvilli brush border contain 4 enzymes: sucrase, lactase, maltase, alpha-dextrinase. As the disaccharides come into contact with these enterocytes, the digestive enzymes hydrolyse them

Question 51

describe the hydrolysis carried out by sucrase, lactase, maltase, alpha-dextrinase

Answer 51

* Lactase hydrolyses lactose into galactose and glucose. * Sucrase hydrolyses sucrose into fructose and glucose. * Maltase and alpha-dextrinase hydrolyse maltose and the glucose polymers into multiple glucose molecules

Question 52

describe the hormonal stimulation of acinar cells to produce inactive pancreatic enzymes

Answer 52

I cells secrete CCK (cholecystokinin) to produce inactive pancreatic enzymes (zymogens) in response to the presence of fats and amino acids

Question 53

describe the hormonal stimulation of ductal cells tin response to acidic chyme

Answer 53

S cells in the duodenum secrete secretin which causes bicarbonate to be released into the small intestine from the pancreas. This neutralizes the potentially harmful acid that comes from the stomach.

Question 54

define chronic pancreatitis

Answer 54

inflammation of the pancreas that does not heal and leads to the permanent impairment of endocrine and exocrine functions.

Question 55

list causes of chronic pancreatitis

Answer 55

```  Heavy alcohol use  Repeated episodes of acute pancreatitis  Autoimmune conditions  Genetic mutations due to cystic fibrosis  Blocked pancreatic or common bile duct  Hereditary  Idiopathic  Hypercalcaemia ```

Question 56

list clinical features of chronic pancreatitis

Answer 56

o Upper abdominal pain radiating to the back - which increases after eating or drinking o Nausea and vomiting o Steatorrhea – frequent, oily, foul-smelling stool, due to malabsorption o Weight loss – due to malabsorption o Diabetes type 1: can affect the ability of the pancreatic islets to produce insulin to regulate blood glucose levels. Can lead to type 1 diabetes. o Jaundice if bile duct is blocked

Question 57

how much destruction to acinar tissue must there be before symptoms of malabsorption present?

Answer 57

90% of acinar tissue

Question 58

list the tests of pancreatic damage

Answer 58

 Serum amylase (normal <100 U/L, low specificity)  Urine amylase (normal 30-600 U/L)  Serum lipase (normal 30-210 U/L, Higher clinical sensitivity and specificity than amylase)

Question 59

list the tests of pancreatic function

Answer 59

– Direct/invasive and indirect function tests – Faecal chymotrypsin – Faecal elastase

Question 60

what is the gold standard invasive/direct test of pancreatic function

Answer 60

Secretin-pancreozymin test - measures pancreatic enzymes e.g. trypsin in duodenum aspirate

Question 61

what is the Lundh test?

Answer 61

an invasive/direct test which measures bicarbonate, amylase or trypsin activity following a meal

Question 62

what do low levels of faecal chymotrypsin and elastase suggest?

Answer 62

Low values indicate pancreatic insufficiency.

Question 63

what other diagnostic test can be used to check for chronic pancreatitis ?

Answer 63

``` Blood Glucose - may be elevated (due to endocrine insufficiency) CT Scan (contrast enhanced) - pancreatic calcifications, enlargement of the pancreas, ductal dilation and vascular problems Abdominal Ultrasound - structural/anatomical changes including inflammation, duct irregularity, irregularity of head/body, calcification. Abdominal X-Ray - pancreatic calcifications MRCP – dye injected into patient’s veins and MRI used. ```

Question 64

describe the management of chronic pancreatitis

Answer 64

 Lifestyle changes – avoiding alcohol  Stop smoking  Change diet – low fat, high protein, high calorie diet with fat-soluble vitamin supplements  Pancreatic enzyme supplements  Steroid medication to relieve the inflammation  Painkillers  Surgery

Question 65

what surgical interventions can be used to treat chronic pancreatitis ?

Answer 65

– Endoscopic lithotripsy – involves using shock waves to break the stones into smaller pieces – Pancreas resection – surgical removal of inflamed area of pancreas – Total pancreatectomy – removal of the entire pancreas

Question 66

what are reasons for poor dug compliance?

Answer 66

– Forgetfulness – May stop taking medication once they start to see results – Impatient with results and think it’s not working – Side effects – Difficulty swallowing pills – Doesn’t understand the importance of taking it

Question 67

what improvements can be made to improve drug compliance

Answer 67

– Maintain good communication and rapport with the patient to develop trust – Ensure that information provided is clear and concise and that they understand reasons for taking it – Check up on patient in follow up consultations to ensure they are taking their medication as advised – Make sure they are well educated and informed about the medical condition and the benefits of the treatment – Recommend ways to help them remember to take it if they are forgetful