GIT Flashcards
Where abouts in the Gastrointestinal tract are you likely to find Haemonchus?
Abomasum
Where abouts in the GIT are you likely to find Trichostrongylus?
Small intestine
How are clinical signs of parasitic gastroenteritis (PGE) caused?
- Removal of something (metabolites, blood)
- Damage to gut lining with loss of body fluids (PLGE -> hypo-proteinaemic oedema)
- Interference with digestion & absorption (damage)
- Blockage of something (gut, bile ducts)
- Irritation of gut-larvae in mucosa -> diarrhoea, XS secretion
- Migration through gut wall -> Ill-thrift, diarrhoea, anaemia, more specific signs.
What is stomatitis?
Diffuse inflammation of the oral cavity mucosa
What are some defence mechanisms of the oral cavity?
- Tough stratified squamous epithelium
- Rapid epithelial regeneration
- Resident microflora occupy attachment sites
- Taste buds reject potential toxins
- Saliva contains digestive enzymes
- Salivary pH
- Swallowing, flushing action
- Mucosal secretions provide physical and chemical protection (IgA and lysozyme)
What are some defence mechanisms of the GIT?
- Saliva
- Resident microflora
- Low gastric pH
- Secreted immunoglobulins
- Vomiting
- Intestinal proteolytic enzymes
- Submucosal phagocytes
- Rapid epithelial turnover
- Increased peristalsis -> diarrhoea
- Adaptive immunity
What are the causes of stomatitis?
Direct injury
- foreign body (needle, grass seed, bones)
- ingested chemicals (detergents, other caustics)
Systemic or local disease
- Viruses (FMD, blue-tongue, rinderpest*[no longer exists])
- Autoimmune disease (pemphigus)
- Uraemia (syndromes associated with renal failure)
What are the various types of Stomatitis?
- Vesicular Stomatitis
- Catarrhal Stomatitis
- Erosive/Ulcerative Stomatitis
- Necrotising Stomatitis
- Papular Stomatitis
- Eosinophilic Granuloma Complex
What is an example of a virus causing vesicular stomatitis in ruminants?
FMD -> affects clovel-footed animals (ruminants & pigs)
- wt loss from inability to eat
- high production losses
- Currently exotic to aust.
- can affect the lips, buccal mucosa, tongue, coronet, interdigital skin & udder)
- main routes of infection are inhalation & ingestion
- causes viraemia, localises in lymphoid tissue and epithelial tissue
Give an example of a disease that causes supporative stomatitis in ruminants?
- Actinobacillosis (‘wooden tongue’)
- tongue enlarged, firn, diffuse, fibrous proliferations & many
granulomas - Multifocal, well demarcated yellow lesions in the retropharyngeal lymph node
Eosinophilic Granuloma Complex commonly occurs in what species?
Cats
- lesser dogs
- often seen in cats with hypersensitivity disorders or allergies
- thought to be hypersensitivity or autoimmune rxn + genetic component
- Identifiable lesions:
1. Indolent (rodent) ulcer
2. Eosinophilic (linear) granuloma
3. Eosinophilic plaque
What are some developmental abnormalities of the oral cavity?
- Cleft lip = Cheiloschisis
- Cleft palate = Palatoschisis
- Malocclusions names according to position of mandible (Brachygnathia = parrot mouth, short mandible; Prognathia = elongated mandible)
- Characteristic breeds e.g. brachycephalic causes dysphagia
List common neoplasias/hyperplasia of the oral cavity in companion animals.
- Gingival hyperplasia -> gingival overgrowth
- Epulis = excessive growth of gingiva
- Viral papillomas
- Neoplasia -> oral melanoma; fibrosarcoma; SCC; chondrosarcoma; osteosarcoma
What are the 3 mechanisms of diarrhoea?
- Osmotic
- Secretory
- Increased permeability
What clinical signs are apparent with intestinal disease?
- Diarrhoea
- Vomiting
- Abdominal pain
- Wt loss
What are the 4 possible intestinal obstructions?
- Stenosis & Atresia
- Extrinsic Obstruction
- Functional Obstruction
- Intestinal Displacements
Stenosis & atresia of the GIT tract can be due to:
- Congenital atresia
- Acquired due to intramural lesion
- Foreign bodies
- Parasites
- Impaction of the colon
- Impaction of the caecum
What are possible extrinsic obstructions of the GIT?
- Neoplasm
- Abscesses
- Peritonitis
- Fibrous adhesions
Displacements of the Intestine
- Herniation: Internal herniation (displacement of intestine through a normal or pathological foramen inside the abdomen e.g. epiploic foraemn entrapment in horses or mesenteric tears
Describe simple gut formation. (development of GIT)
- Formed during folding of embryonic disc.
- gut lumen derived from cavity of yolk sac
- part of yolk sac cavity is incorporated into the folding embryonic disc (body) as the lumen of the primitive gut
Name the simple gut wall layers. (what they are formed from)
Endoderm -> epithelial lining
Splanchnic mesoderm -> remainder of wall
Describe the formation of the liver.
Arise from the foregut.
- Diverticula from the hepatic diverticum include the ventral pancreatic diverticulum & the cystic diverticulum (gall bladder)
- Primordial liver: composed of hepatic diverticulum (endoderm forms hepatocytes, bile caniculi & hepatic ducts; splanchnic mesoderm forms the CT framework of the liver)
- Expansion of hepatic diverticulum -> engulfs vitelline and umbilical veins (-> hepatic sinusoids); Ductus venosus (within liver primordium) links umbilical v with caudal vena cava.
- Primordial liver expands through ventral mesentery & contacts septum transversum.
- Liver surface remains adherent to diaphragm in adult
Describe the formation of the pancreas.
Foregut –> Ventral & Dorsal diverticulum.
Fusion of the 2 diverticula makes the pancreatic body & lobes
- Occurs as gut wall expands
- Duel origin reflected in presence of 2 pancreatic ducts in horse & dog ( major duodenal papilla and minor duodenal papilla) whereas 1 pancreatic duct regresses in pigs, ruminants & cats
What structures are associated with the foregut?
oesophagus, lungs, stomach, pancreas & liver