Pancreas Flashcards

1
Q

What level does the pancreas lie horizontally

A

L1

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2
Q

Is the pancreas intra or retroperitoneal

A

Retroperitoneal

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3
Q

What is the pancreas composed of

A

Head
Neck
Body
Tail

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4
Q

Where on the pancreas does the shape of the duodenum sit

A

Head

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5
Q

What does the pancreas form

A

Part of the posterior wall of the lesser sac

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6
Q

Where does the splenic artery lie to the pancreas

A

Runs towards the spleen embedded in the upper border of the pancreas

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7
Q

Where does the splenic vein lie to the pancreas

A

Posterior

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8
Q

What are the main functions of the pancreas

A

Endocrine and exocrine functions

Synthesises and secretes insulin and glucagon

Pancreatic juices that contain digestive enzymes

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9
Q

Where do the bile duct and main pancreatic duct merge

A

Hepatopancreatic ampulla

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10
Q

Where does the hepatopancreatic ampulla open into

A

Second part of the duodenum at the major duodenal papilla

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11
Q

What is the main blood supply to the pancreas

A

Coeliac trunk
Superior mesenteric artery

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12
Q

Where does the splenic artery supply the pancreas

A

Major branch from coeliac trunk

Runs along upper border of pancreas

Gives ride to pancreatic arteries

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13
Q

Describe the gastroduodenal artery and the pancreas

A

From coeliac trunk

Gives rise to superior pancreaticoduodenal arteries

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14
Q

What does the superior mesenteric artery give rise to

A

Inferior pancreaticoduodenal arteries

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15
Q

What is the innervation of the pancreas

A

Parasympathetic

Sympathetic

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16
Q

What is the parasympathetic innervation of the pancreas

A

Vagus nerve

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17
Q

What is the sympathetic innervation of the pancreas

A

Greater and lesser splanchnic nerves

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18
Q

What are the exocrine secretions of the pancreas

A

Aqueous bicarbonate secretion

Enzyme secretion

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19
Q

Describe aqueous bicarbonate secretion by the pancreas

A

Epithelial cells in PD produce HCO3- and H2O

Bicarbonate secretion protects duodenal mucosa by neutralising stomach acid

Buffers duodenal contents to optimise pH for enzyme digestion

Resting phase maintains low flow - predominantly Na+ and Cl- ions

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20
Q

How much bicarbonate is secreted by the pancreas a day

A

1L/24 hours

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21
Q

Describe enzyme proteases by the pancreas

A

Majority occurs in the small intestine

Stored as proenzymes

Protein digestion

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22
Q

What are the pancreatic proteases

A

Trypsin

Chymotrypsin

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23
Q

What is trypsinogen activated by

A

Enterokinase

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24
Q

What does trypsin activate

A

Chymotrypsinogen

Additional trypsinogen

25
Q

Describe enzyme lipases in the pancreas

A

Hydrolyse triglycerides to monoglycerides and free fatty acids

Bile salts aid

26
Q

What is fat digestion dependant upon

A

Pancreatic and hepatic secretions

27
Q

What is orlistat

A

Pancreatic lipase inhibitor

28
Q

Describe enzyme amylase in the pancreas

A

Hydrolyses start to maltose and maltotriose and limit dextrin

Major source of amylase

29
Q

What are the stages in which there is pancreatic enzyme secretion

A

Cephalic stage - vagal innervation and gastrin
- low level stimulus in anticipation of a meal

Intestinal stage
- secretin
- cholecystokinin
- gastrin

30
Q

What is the role of cholecystokinin on pancreatic enzyme release

A

Pancreatic enzyme and HCO3- secretion

Gallbladder contraction

Inhibition of gastric acid secretion

Delay gastric emptying

31
Q

What is the stimulus for cholecystokinin

A

HCl
Proteins
Fats entering duodenum

32
Q

What is the role of secretin in pancreatic enzymes

A

Pancreatic water and bicarb secretion - carrying enzymes

33
Q

What do gastrin and CCK do

A

Stimulate enzyme secretion

Neutralise gastric acid entering small intestine

34
Q

How long is the pancreas

A

12-15cm

35
Q

What is the pathway of secretions

A

Pass into smaller ducts, then 2 larger ducts

36
Q

What is the formation of the pancreas

A

Formed by small clusters of glandular epithelial cells

98-99% of cells are clusters = acini

37
Q

What cells are exocrine activities performed by

A

Acinar cells

38
Q

What cells are endocrine activities performed by

A

Islet cells

39
Q

Describe the exocrine activity of the pancreas

A

Manufacture and secrete fluid and digestive enzymes (pancreatic juice) which is released into the gut

40
Q

Describe endocrine activity of the pancreas

A

Manufacture and release several peptide hormones into the portal vein

41
Q

What is the site of insulin and glucagon secretion in the endocrine pancreas

A

Islet of Langerhans

42
Q

What % of the total volume do the islets of langerhan make up

A

2-3%

43
Q

What are the cells in the islets of langerhans which have important functions

A

Beta cell

Alpha cell

Delta cell

Paracrine ‘crosstalk’ between alpha and beta cells e.g. local insulin releases inhibits glucagon

44
Q

What do beta cells secrete

A

Insulin

45
Q

What do alpha cells secrete

A

Glucagon

46
Q

What do delta cells secrete

A

Somatostatin

47
Q

What are the peptides secreted by the islets of Langerhans

A

Insulin

Glucagon

48
Q

What is the role of insulin

A

Reduces glucose output by liver, increases storage of glucose, fatty acids, amino acids

49
Q

What is the role of glucagon

A

Mobilises glucose, fatty acids and amino acids from stores

50
Q

What role does somatostatin play in insulin and glucagon secretion

A

Inhibitor

51
Q

Describe the role of insluin

A

Supresses hepatic glucose output
- decrease glycogenolysis and gluconeogenesis

Increases glucose uptake to insulin sensitive tissue
- muscle and fat

Supresses
- lipolysis
- breakdown of muscle (ketogenesis)

52
Q

Describe the role of glucagon

A

Increases hepatic glucose output
- increases glycogenolysis and gluconeogenesis

Reduces peripheral glucose uptake

Stimulates peripheral release of glycogenolysis precursors
- lipolysis
- muscle glycogenolysis and breakdown

53
Q

What happens is blood glucose >6 (too high)

A

Short-term
- make glycogen (glucose to glycogen = glycogenesis)

Long-term
- make triglyceride (lipogenesis)

54
Q

What happens if blood glucose is <4 (too low)

A

Short term
- split glycogen (glycogen to glucose = glycogenolysis)

Long term
- make glucose (gluconeogenesis) from amino acids/lactate

55
Q

Where are primary glucose sensors

A

Pancreatic islets

Also in medulla, hypothalamus, carotid bodies

Sensory cells in gut wall stimulate insulin release - incretins

56
Q

Describe insulin secretion by the B-cell

A

Glucose enters cell via GLUT2 glucose transporter

Glucose metabolism into cell

Ca2+ channels open
Insulin secretory granules
Insulin secretion

57
Q

Describe insulin release by proinsulin

A

Contain A and B chains of insulin joined by C peptide

Presence of C peptide implies endogenous insulin production

58
Q

Describe biphasic insulin release

A

B-cells sense rising glucose and aim to metabolise it

1st phase response is rapid release of stored product

2nd phase response is slower and as it is release of newly synthesised hormone