Large intestine Flashcards
describe the anatomical locations from the start to the end of the large intestine
terminal ileum ileocecal valve caecum ascending colon transverse colon descending colon sigmoid colon rectum
what are haustra
small pouches caused by sacculation (sac formation), which give the colon its segmented appearance
Haustral contractions are slow segmenting, uncoordinated movements that occur approximately every 25 minutes.
what is a barium enema
X-ray used to detect abnormalities of the large intestine via rectum injection
describe the layers of cells from the ,men to the outside in the large intestine
simple columnar epithelium mucous cells intestinal cells intestinal gland muscular mucosal submucosa musculares externa
what is the musclaris external made out of in the large intestine
longitudinal muscle and circular layer
describe the role of the ileoceacal valve
flutter valve is one way
there is periodic relaxation which allows flow to occur
ill distention opens it
caecal distension closes it
what is haustration
slow contractions of circular muscle squeeze contents to and fro as in segmentation
what is mass movement
few times a day there is a peristaltic wave
what is motility in the colon NOT for
moving contents along
what happens to haustra during mass movement
they disappear
what is control of the control one by
intrinsic via the enteric nervous system (some para control)
where do enteroendocrine and neurocrine influences come from in the colon
cells releasing 5-HT and Peptide YY
what reflexes trigger mass movements
gastrocolic and orthocolic
what causes digesting in the colon
bacteria not enzymes
what do bacteria turn these substances into fibre urea + amino acids cysteine/methionine bilirubin primary bile acids conjugated bile acids fermentation
short chain fatty acids such as butyric acid hydrogens nd methane ammonia hydrogen sulphide urobilligen and stercobillins secondary bile acids unconjugated bile acids 1L nitrogen, hydrogen and CO1
