Small Intestine Flashcards
functions of the small intestine
- digestion
- absorption
- endocrine and neuronal control functions
- barrier functions
barrier functions of small intestine
maintaining a barrier against pathogens
- immune sampling
- monitoring the presence of pathogens
- translocation of bacteria
- gut associated lymphoid tissue (GALT)
average length of small intestine
250-450cm
describe the presence of bacteria in the small intestine
low bacterial population due to toxic environment
what creates the toxic environment of the small intestine
digestive enzymes
bile salts
presence of IgA etc.
how does the small intestine function to maintain body control
- decontaminates dirty food
- requires a lot of fluid
- controlled hydrolysis to avoid fluid shifts
- sophisticated control of motility
- absorption against gradients
- onward processing in the liver
what are the primary enzymes responsible for the break down of proteins
trypsin
chymotrypsin
what are proteins normally broken down to
amino acids
oligopeptides
what is the primary fat digestive enzyme
pancreatic lipase
what is fat broken down into
glycerol
free fatty acids
describe the absorption of glycerol and free fatty acids
absorbed via lacteal and the lymphatic system
primary carbohydrate digestive enzymes
pancreatic amylase
what are carbohydrates broken down to
disaccharides
what happens to disaccharides at the brush border of cells
final digestion and absorption
symptoms of small bowl disorders (general)
- weight loss
- increased appetite
- diarrhoea
- abdominal bloating
- fatigue
- sometimes steatorrhoea
what causes steatorrhoea
fat malabsorption resulting in high fat content in stool
describe stools of steatorrhoea
less dense floats pale foul smelling difficult to flush may leave an oily mark
signs of small bowl disorder
- signs of weight loss
- low or falling BMI
signs of vitamin D deficiency
tetant
osteomalacia
signs of vitamin A deficiency
Night blindness – eyesight during day fine, at night cant see
signs of vitamin K deficiency
raised PTR
signs of vitamin B complex deficiency
-thiamine deficiency causing memory problems/ dementia
Niacin - dermatitis, unexplained heart failure
signs vitamin C deficiency
scurvy
what can clubbing be a sign of small bowl
- coeliac
- crohns
what can aphthous ulceration be a sign of small bowl
coeliac
crohns
tests of small bowl structure
- biopsy
- study using barium
- CT
- MRI enterography
- capsule enterography
- white cell scan
what is capsule enterography
little pill with the camera that you swallow
what is the test for bacterial overgrowth in the large intestine, and why is this relevant to the small intestine
H2 breath test
large bowl is getting a lot of unabsorbed food cause small bowl is not functioning properly, and the bacteria feed on this producing hydrogen
what are the primary serology tests for coeliac disease most - least reliable
serum IgA
Anti TTG IgA
IgG
iatrogenic meaning
relating to illness caused by medical examination or treatment.
explain the reliability of H2 breath test, and how the results should be interpreted
Positive result = reliable, treat with rotating antibiotics
Negative result = not reliable,. the patient may still have a bacterial overgrowth and its just not been detected. If there is no alternative diagnosis, and suspect they have one, give them a cycle of rotating antibiotics to see if it makes a difference
describe the treatment of bacterial overgrowth
rotating antibiotics @ 2 weeks each
- metronidazole
- tetracycline
- amoxycillin
