Crypt villus unit dynamics and small intestinal cell responses

what is absorbed by the vilus?

• CHO

• amino acids

• lipids

• Fe,Ca, Cu, Zn, H2O, ions (Na+, K+, Cl-, HCO3-)

how do goblet cells respond to inflammation?

• cytokines e.g. IL-6 may induce hyperplasia but chornic inflammation involving TNF-a and IFN-y

• associated with hypoplasia and reduced secretion

what kind of feedback mechanism might operate to tell crypt to work quickly to reform vilus?

• negative feedback loop

what will hapen to the absorptive area of the SI when affected by rotaviruses?

• decrease

what in particular does high levels of radiation target?

• nucleus of crypt cellsw

where might the effects of radiation be felt most in the gut?

• enterocytes and goblet cells - impaired mucosal barrier and increasd inflammatory markersif

if radiation exposure killed all cells in a crypt but left some of deep stem cells intact, how long would it take for cypts and then vilus units re-form

• crypt 21 days

  • vilus - 2-5 days

what do we call viruses that attack rapidly dividing crypt cells?

• radiomimetic viruses

what is the most common radiomimetic virus that causes problems?

• parvoviruswh

what clinical signs would you expect to see radiomimetic viruses?

• leukopenia and haemorrhagic diarrhoea