Unit 3 - GI Lecture 1 Flashcards
What is the most vital structural defense in the digestive tract?
the mucosal epithelium
What is the role of the mucosal epithelium in the digestive tract?
it forms a physical barrier between the luminal contents and the more susceptible deeper structures
What can losing mucosal integrity lead to (generally)?
focal fungal/bacterial infection of surface mucosa or access of organisms to depper tissues leading to bacteremia/septicemia
How does ruminal acidosis lead to mycotic rumenitits?
ruminal acidosis causes a disruption of mucosal intergity allowing normal rumen fungi to colonize mucosal defects and cause mycotic rumenitis
How does gastrointestinal venous drainage pass through the liver?
the GIT mucosal integrity is lost, the bacteria enter venous circulation and thus there is a bacterial infection of the liver
What is the result of gastrointestinal venous drainage passing through the liver?
multifocal hepatic abscesses
What are the biochemical protective mechanisms of the digestive tract?
gastic acid secretion, buffers in secretions, mucus, and secretion of digestive enzymes in an inactive proenzyme form
What are consequences of biochemical protective mechanism failure?
microbial overgrowth and gastric ulceration
What is achlorhydria?
when there is no gastric acid in the stomach
What does achlorhydria lead to?
microbial overgrowth, an increased risk of infections, and diarrhea
What can cause gastric ulceration?
NSAIDs cause decreased production of gastric mucus and bicarbonate which can facilitate gastric ulcer formation
What is the pathogenesis of NSAIDs causing ulcer formation?
- NSAIDs
- Decreased prostaglandin E2 production
- Decreased bicarbonate and decreased mucus secretion and decreased blood flow
- gastic ulcer formation
How is motility in the digestive tract a protective mechanism?
it keeps ingesta, secretions and gas moving through the intestinal tract with eventual removal of waste products and does not allow organisms to build up in segments of the GIT
What is the consequence of failure of motility in the GI tract?
localized bacterial overgrowth
What can predispose to pigs to get E.coli enteritis?
low temperatures due to decreased peristalsis
How are microflora protective mechanisms of the GIT?
colonization with commensal bacteria and protozoa aids digestion, stimulates proper mucosal development and helps to prevent pathogenic organisms from attaching and invading the mucosa
What can result in aberrant microflora?
neonates not having competitive microflora, disruption by dietary changes, and disruption by antibiotics
How does Clostridium difficile colonize?
the colonic flora are disrupted by antibiotics
How is inflammation and nonspecific immunity protective in the GIT?
inflammation and nonspecific immunity helps control invasion of organisms, specific humoral and cell mediated immunity act locally and systemically to eliminate specific pathogenic organismsf
What is TGE?
transmissible gastroenteritis
What is TGE caused by?
coronavirus
What is largely protective against TGE?
lactogenic immunity
When are pigs most susceptible to TGE?
when they are less than 2 weeks of age
What are the structures in the upper digestive tract?
oral cavity (teeth, tongue, mucosa, pharynx), esophagus, forestomachs
What population of dogs is retained deciduous teeth common in?
toy breeds
How can retained deciduous teeth cause disease?
- Permanent teeth to erupt in abnormal positions
- Overcrowding of teeth
- Accidental bites to the palate/gums
- Abnormal jaw position
- Development of plaque with associated gingivitis/periodontal disease
What is enamel formed by?
ameloblasts