237: Malabsorption/ Chronic Diarrhoea

Question 1

things that cause osmotic diarrhoea:

Answer 1

magnesium, sulfate, phosphate, sugars ( mannitol, sorbitol, lactase deficiency, lactulose)

Question 2

secretory diarrhoea causes:

Answer 2

cholera toxin,
endogenous (neuroendocrine tumour),
loss of interstitial surface (IBD, Coeliac, surgical resection),
intestinal ischemia,
rapid intestinal transit (dumping syndrome).

Question 3

role: stomach

Answer 3

body/corpus:
chief cells -pepsinogen;
parietal cells - HCL and Intrinsic factor

Antrum:
chief cells. 
G cells (gastrin)
D calls (somatostatin)
HCO3

Question 4

role: Duodenum

Answer 4

Digestion: chyme is mixed with bile to form chylomicrons
Absorption: Mg, Iron, Ca, Z

NB: coeliac disease is specific to the duodenum - 1st point hat gut is exposed to isolated gluten.

Question 5

role: liver

Answer 5

digestion: bile salts - fats to micelles
detox: chemicals from systemic and portal blood
manufacture: sugar, protein (clotting factors, albumin)
storage of glycogen

Question 6

role: pancreas

Answer 6

duct cells: bicarb

acinar cells: pancreaic juices act on macronutrients - trypsinogen, chymotrypsin, elastase, amylase, lipases

Question 7

role: jejunum

Answer 7

absorption, ADEK, folate, Ca, minerals, trace elements, proteins, monosaccharides

Question 8

role: proximal ileum

Answer 8

fat and FSV (ADEK) water and WSVits,

Question 9

role: distal ileum

Answer 9

bile salt and Intrinsic factor reabsorption

vit b12 and folate.

Question 10

role: ileo-caecal valve

Answer 10

paces flow of chyme out of the ileum to provide time for fat and bile absorption.
prevents bacterial contamination of ileum.

Question 11

role: colon

Answer 11

water and short chain fatty acid absorption

Question 12

Site of production and action of: cholecystokinin

Answer 12

Source: duodenum, jejunum, ileum, colon
Target: pancreas (start enzyme secretions), gall bladder (contract)

Question 13

site of production and action of : gastrin

Answer 13

source: g cells in gastric antrum
target: parietal cells in gastric body H+ secretion

Question 14

site of production and action of : gastrin releasing hormone

Answer 14

source: vagal nerves
target: G cells in gastric antrum (release gastrin)

Question 15

site of production and action of : glucagon

Answer 15

source: beta cells Islets of langerhans in pancreas
Target: Liver to release glucose

Question 16

Site of production and action of : Guanylin

Answer 16

Source: ileum, colon goblet cells induces chloride secretion
Target: small and large intestine.

Question 17

site of production and action of : Somatostatin

Answer 17

Source: D cells stomach and duodenum; delta cells pancreatic islets
Target:
Stomach- reduced gastrin;
intestine -reduce fluid losses;
pancreas - reduce secretions ( endo and exo)
liver - reduce bile flow

Question 18

site of production and action of : vasoactive intestinal peptide (VIP)

Answer 18

source: Enteric Nervous System neurons
target:
Small I: increase secretions and relax smooth muscle
Pancreas: increase secretions,

Question 19

chronic diarrhoea :

Answer 19

> 4 weeks

Question 20

how do you diagnose lactose intolerance?

Answer 20

hydrogen breath test. ( bacteria in the gut produce more hydrogen as they ferment the lactose)

Question 21

what do you need to digest fat?

Answer 21

bile salts to emulsify it (gall bladder)
lipase (pancreas)
ileum to absorb
terminal ileum to mop up bile salt

Question 22

Deficiency: Vit A

Answer 22

night blindness, xerophthalmia (corneal ulceration due to dry eye), benign intracranial hypertension

Question 23

Vit D deficiency

Answer 23

bones: rickets, osteomalacia

Question 24

vitamin E deficeincy

Answer 24

oxidant stress : CV disease and haemolysis

neurological: nerve membrane structure and function…peripheral neuropathy, ataxia, external ophthalmoplegia.

Question 25

vitamin K deficiency

Answer 25

coagulation prolonged PT