week 3

Question 1

endocrine function of pancreas

Answer 1

islets of langerhans secrete insulin, glucagon, somatostatin, polypeptides

Question 2

exocrine function of pancreas

Answer 2

secretory acini
role in digestion and absorption
pancreatic juice secreted - enzymes, sodium bicarbonate
enzymes include amylase, lipase, trypsin, chymptrypsin, esterases

Question 3

acute pancreatitis signs and symptoms

Answer 3

sudden onset of abdo pain, nausea, vomiting, fever, hypotension, shock, multi-organ failure
increase in amylase, lipase and urea
decrease in albumin and calcium

Question 4

acute pancreatitis causes

Answer 4

exact pathogenesis uncertain - duct obstruction, acinar cell injury, hereditary
gallstones
alcohol
metabolic: hypertriglyceridaemia, hypercalcaemia
drugs
trauma
infections eg mumps
ampullary or pancreatic tumours

Question 5

what is chronic pancreatitis

Answer 5

irreversible pancreatic damage leading to destruction of both exocrine and endocrine function
often secondary to repeated acute attacks or alcohol
other causes are hypercalcaemia, idiopathic, tropical

Question 6

signs and symptoms of chronic pancreatitis

Answer 6

recurrent abdo pain radiating to back
diabetes mellitus due to loss of islet cells
weight loss and steatorrhoea due to malabsorption - 90% of acinar tissue has to be lost before symptoms of malabsorption

Question 7

tests of pancreatic damage and results

Answer 7

serum amylase - blood amylase is low and constant but greatly increase in acute pancreatitis or salivary gland inflammation - rises within 5-8 hours of onset and normalises by day 4 - low specificity
urine amylase - can help exclude macroamylasaemia when serum amylase increases but urine amylase decreases
serum lipase - rises within 4-8 hours of onset of symptoms, peaks at 24, hours and normalises within 8-14 days - higher sensitivity and specificity

Question 8

faceal tests

Answer 8

faecal chymotrypsin and elastase - low values indicate pancreatic insufficiency

Question 9

function of chymotrypsin and elastase

Answer 9

c - acts on peptide bonds in which carboxyl group is provided by tyrosine and phenylalanine
e - broad specificity on attacking bonds nect to small amino acids

Question 10

what is coeliac disease

Answer 10

a common chronic, immune-mediated enteropathy that is triggered and maintained by ingestion of gluten in genetically predisposed individuals
various degrees of intestinal inflammation ranging from intraepithelial lymphocytes to severe infiltration and total villous atrophy coupled with crypt hyperplasia

Question 11

who should be tested for coeliac disease

Answer 11

those with symptoms such as diarrhoea, dyspepsia, chronic abdo pain, vomiting, chronic constipation, anorexia, weight losee

Question 12

how do you test for coeliac disease

Answer 12

the patient must be on gluten-containing diet
serology - IgA deficiency
duodenal biopsy - histology, immunohistochemistry, human leucocyte antigen, small bowel imaging

Question 13

how do you manage coeliac disease

Answer 13

gluten free diet - dietician review, GP FP10 prescription
nutritional assessment
bone health
vaccination - pneumococcus, menigococcus
follow up with dietician until antibodies normal and diet established

Question 14

what are the main complications of coeliac disease

Answer 14

infection - howell-jolly body and target cells

functional hyposplenism

Question 15

pathophysiology of coeliac disease

Answer 15

proteases cannot digest gluten

gluten peptides are deamminated by TTG

Question 16

pathophysiology of coeliac disease

Answer 16

proteases cannot digest gluten
gluten peptides are deamminated by tTG and presented to APCs
if you have HLA DQ2/8 then APCs can provoke t and b cells to produce anti-gluten antibodies
these induce cytokine cascades which drives the inflammation process

Question 17

enteropathy associated t-cell lymphoma

Answer 17

type 1 is strongly associated with coeliac and HLA-DQ2

Question 18

absorption of iron

Answer 18

predominantly in duodenum
haem iron easily absorbed into enterocytes
non-haem iron released from food by acid digestion and proteolytic enzymes in stomach
non haem iron must be reduced from ferric to ferrous state by duodenal cytochrome b1 - influenced by vitamin c
iron is taken into enterocyte through the divalent metal transporter 1 (DMT1)
exported from enterocyte to the circulating plasma transferrin through ferroprotein (transmembrane protein) and the circulating hormone hepcidin

Question 19

transport of iron

Answer 19

transferrin transports iron in plasma
it is a glycoprotein synthesised in hepatocytes - has 2 iron binding domains
30% saturated with Fe

Question 20

storage and recycling of iron

Answer 20

effete RBCs are removed by the macrophages of the reticuloendothellial system
RES stores around 500mg of iron
it is stored in ferritin/haemosiderin
releases iron to transferrin in plasma
Tf-iron taken up via Tf receptors on erythroblasts, hepatocytes

Question 21

regulation of iron metabolism

Answer 21

regulation of dietary iron absorption is the single physiological mechanism responsible for maintaining our iron balance
there is no excretory mechanism for iron
interaction between ferroprotin and hepcidin is the most important regulator of GI iron absorption and RES iron release

Question 22

hereditary haemochromatosis

Answer 22

increase in iron, ferrin and transferrin saturation
abnormalities of the HFE gene - reduces hepcidin production
increased GI iron absorption and increased RES iron release

Question 23

RES iron release

Answer 23

RES macrophages acquire iron from effete RBCs and the iron is sorted as ferritin or haemosiderin
release is controlled by ferroportin and hepcidin

Question 24

iron deficiency anaemia RBCs

Answer 24

small and pale

not enough haemoglobin

Question 25

role of hepcidin in iron metabolism

Answer 25

it reduces the levels of iron in plasma
hepcidin binds ferroportin and degrades it - reduces GI iron absorption and reduces macrophage iron release from the RES
it is synthesised in the liver
hepcidin loss causes increased GI iron absorption