General Concepts in Intestinal Disease Flashcards
where is water secreted?
small intestine
where is the microbiome important?
large intestine
in which species does the microbiome in the large intestine play a major role?
horses
rodents
rabbits
what do goblet cells do?
produce and secrete components of mucus
what are most of the crypt epithelial cells?
multipotent stem cells
microvilli are coated by a ________________, a matrix of oligosaccharides, along with (secreted) digestive enzymes
glycocalyx
where are paneth cells?
inhabit base of crypts in some species: primates, horses, rodents
what are some functions of paneth cells?
secretory and phagocytic
produce antimicrobials: lysozyme and defensins
protective niche around stem cells
what type of cells are interstial cells of cajal?
mesenchymal cells
what do the interstitial cells of cajal do?
regulate gut motility
what are microfold (M) cells involved in?
uptake of antigens from intestinal lumen: transfer them to underlying lymphoid tissue
for which pathogens are microfold (M) cells portals of entry?
salmonella
shigella
rhodococcus
yersinia
bovine viral diarrhea virus
what can disruption of the microbiome lead to?
intestinal dysbiosis: diarrhea, abdominal pain/colitis, systemic disease
what can Clostridial overgrowth and toxin production lead to?
ulcerative and necrohemorrhagic colitis
what are the mechanisms of intestinal diseases?
inflammation
necrotizing processes
lymphangiectasia: disorders of fluid drainage
disorders of innervation
diarrhea
what are some targets of infectious agents in the small intestine?
absorptive enterocytes
crypt cells
microvilli and glycocalyx
what are the clinical manifestations of intestinal disease?
vomiting
diarrhea
acute abdomen/colic
protein-losing enteropathy
what are the inputs to the vomiting center?
chemoreceptor trigger zone
gastrointestinal tract peripheral sensory receptors
vestibular centers
cerebral cortex
what is dysphagia?
oropharyngeal disease: defective swallowing
what are the mechanisms for diarrhea?
osmotic/malabsorption/maldigestion
secretory
inflammatory/exudative
abnormal motility
what does secretion of water follow?
chloride
what does absorption of water (and many solutes) follow?
sodium
what can lead to secretory diarrhea?
altered ion transport
bacterial enterotoxins
endogenous secretogogues
where is water absorbed?
small intestine
large intestine
how often do crypt epithelial cells divide?
every 24 hours
how are goblet cells spread out from the duodenum to the rectum?
increases from duodenum to rectum
what are crypt epithelial cells important for?
give rise to absorptive and secretory cells
secrete chloride
what do enterochromaffin cells produce?
gastrointestinal hormones and peptides such as gastrin, gastric inhibitory peptide, cholecystokinin, glucagon, somatostatin, vasoactive intestinal peptide, motilin, substance P, neurotensin, secretin, serotonin
where are the interstitial cells of cajal?
between muscle layers and myenteric plexus
why are normal commensal microbes important?
produce nutrients for epithelial cell health/metabolism
can limit pathogens’ ability to colonize
promote immunological tolerance to luminal contents
what do infectious agents target in the small intestine?
absorptive enterocytes
crypt cells
microvilli and glycocalyx
is there a blood:brain barrier at the chemoreceptor trigger zone?
no
what is dysphagia and what is it from?
defective swallowing
oropharyngeal disease
where in the intestinal wall are water and products of digestion absorbed?
tips of villi
can extra-abdominal disease be a sign of acute abdomen?
yes: pleuropneumonia
what is the main thing you might see with protein losing enteropathy?
effusions/edema
what can cause protein losing enteropathy in small animals?
any disease disrupting intestinal wall function
blood sucking parasites
+/- GI hemorrhage
what can cause protein losing enteropathy in large animals?
parasitism
johne’s disease ruminants
infectious enterocolitis
idiopathic inflammatory bowel diseases
lymphoma
gastrointestinal ulcers
if the basement membrane is intact in a ulceration or injury, how is the prognosis?
good
