237: Malabsorption/ Chronic Diarrhoea Flashcards
(25 cards)
things that cause osmotic diarrhoea:
magnesium, sulfate, phosphate, sugars ( mannitol, sorbitol, lactase deficiency, lactulose)
secretory diarrhoea causes:
cholera toxin,
endogenous (neuroendocrine tumour),
loss of interstitial surface (IBD, Coeliac, surgical resection),
intestinal ischemia,
rapid intestinal transit (dumping syndrome).
role: stomach
body/corpus:
chief cells -pepsinogen;
parietal cells - HCL and Intrinsic factor
Antrum: chief cells. G cells (gastrin) D calls (somatostatin) HCO3
role: Duodenum
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.
role: liver
digestion: bile salts - fats to micelles
detox: chemicals from systemic and portal blood
manufacture: sugar, protein (clotting factors, albumin)
storage of glycogen
role: pancreas
duct cells: bicarb
acinar cells: pancreaic juices act on macronutrients - trypsinogen, chymotrypsin, elastase, amylase, lipases
role: jejunum
absorption, ADEK, folate, Ca, minerals, trace elements, proteins, monosaccharides
role: proximal ileum
fat and FSV (ADEK) water and WSVits,
role: distal ileum
bile salt and Intrinsic factor reabsorption
vit b12 and folate.
role: ileo-caecal valve
paces flow of chyme out of the ileum to provide time for fat and bile absorption.
prevents bacterial contamination of ileum.
role: colon
water and short chain fatty acid absorption
Site of production and action of: cholecystokinin
Source: duodenum, jejunum, ileum, colon
Target: pancreas (start enzyme secretions), gall bladder (contract)
site of production and action of : gastrin
source: g cells in gastric antrum
target: parietal cells in gastric body H+ secretion
site of production and action of : gastrin releasing hormone
source: vagal nerves
target: G cells in gastric antrum (release gastrin)
site of production and action of : glucagon
source: beta cells Islets of langerhans in pancreas
Target: Liver to release glucose
Site of production and action of : Guanylin
Source: ileum, colon goblet cells induces chloride secretion
Target: small and large intestine.
site of production and action of : Somatostatin
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
site of production and action of : vasoactive intestinal peptide (VIP)
source: Enteric Nervous System neurons
target:
Small I: increase secretions and relax smooth muscle
Pancreas: increase secretions,
chronic diarrhoea :
> 4 weeks
how do you diagnose lactose intolerance?
hydrogen breath test. ( bacteria in the gut produce more hydrogen as they ferment the lactose)
what do you need to digest fat?
bile salts to emulsify it (gall bladder)
lipase (pancreas)
ileum to absorb
terminal ileum to mop up bile salt
Deficiency: Vit A
night blindness, xerophthalmia (corneal ulceration due to dry eye), benign intracranial hypertension
Vit D deficiency
bones: rickets, osteomalacia
vitamin E deficeincy
oxidant stress : CV disease and haemolysis
neurological: nerve membrane structure and function…peripheral neuropathy, ataxia, external ophthalmoplegia.
