Digestive System Lecture 1 PDF

Digestive System Lecture 1  Anatomy Oral cavity & pharynx Esophagus Stomach (simple or complex) Intestines (Small and Large) Liver & pancreas Peritoneum Signs of GI Disease  Portals of entry of pathogens 1. Ingestio...

Digestive System Lecture 1  Anatomy Oral cavity & pharynx Esophagus Stomach (simple or complex) Intestines (Small and Large) Liver & pancreas Peritoneum Signs of GI Disease  Portals of entry of pathogens 1. Ingestion (most common) 2. Coughed up & swallowed 3. Systemic blood-borne infections 4. Parasite migration  Oral Cavity Oral mucous membranes Teeth Tonsils Salivary glands Tongue  Palatoschisis (cleft palate) Fissure in the hard palate Result in communication between the oral and nasal cavities Animals often die of an aspiration pneumonia Aspiration pneumonia (Drenching pneumonia): pneumonia that develops due to the entrance of foreign materials into the bronchial tree  Causes Genetic Toxic plants (Veratrum californicum) Cheiloschisis (cleft lip or hare lip)  STOMATITIS Inflammation of the oral cavity Cheilitis -lips Glossitis -tongue Gingivitis -gums Pharyngitis -pharynx Tonsillitis -tonsils Sialoadenitis -salivary glands Causes of stomatitis Infectious agents Trauma Chemical injury Auto-immune Systemic diseases  Classification Superficial stomatitis: Limited to the mucosa 1. Vesicular stomatitis 2. Erosive and ulcerative stomatitis Deep stomatitis: Extended to the submucosa 1. Necrotic stomatitis 2. Granulomatous stomatitis  Vesicular stomatitis  Characterized by vesicle formation  Vesicle: Fluid-filled raised lesion  Epithelial damage (viral) intracellular edema cell rupture Intercellular edema (vesicles) erosions ulcers cellular infiltration In dogs & cats In food/large animals: 1. Auto-immune disease 1. Foot and mouth disease (Cattle sheep, Pigs) 2. Calicivirus infection in cats 2. Vesicular stomatitis (Horse, cattle, Pig) (Rhabdovirus )  Foot and Mouth Disease  picornavirus  Highly contagious, high morbidity, low mortality  Affects mainly ruminants and pigs GROSS FINDINGS 1- oral mucosa, feet (along coronary band), udder 2- vesicles > may rupture leaving ulcers 4- Gray/yellow myocardial necrosis (“tiger heart”) in animals less than 6 months of age Erosive & Ulcerative Stomatitis Erosion Ulcer  Erosion: loss of surface epithelium with intact basement membrane  Ulcer: loss of the epithelial with destruction of the basement membrane revealing the underlying submucosa (blood vessels)  BVD (Bovine viral diarrhea)  MCF  Rinderpest  Peste des petits ruminants  Bluetongue  FMD  Herpesvirus(Cattle, cats, horses, primates)  Uremia  Dog Uremic ulcers in dogs  Bovine popular stomatitis  Parapoxviruses  Mainly young animals  circular, coin-shaped papules and ulcers often have a hyperemic, thickened periphery Papule: Elevated round firm lesion less than 1 cm  Necrotizing Stomatitis  Characterized by tissue necrosis  Example: calf diphtheria caused by Fusobacterium necrophorum  Granulomatous Stomatitis  Characterized by granuloma formation Example: Actinobacillosis(wooden tongue)  Actinobacillus lignieresii (Gram negative)  Affects cattle, sheep  Grossly: 1. The tongue is firm, pale containing multifocal nodules. 2. Containing Yellow pus"sulfur granules” 3. Massive amount of fibrous connective tissue (arrow head) Microscopically: a pyogranuloma 1. In the Center, a mass of the bacteria 2. Surrounded by radiating eosinophilic clubs 3. Surrounded by neutrophils 4. macrophages , giant cells, Lymphocytic , plasma cells 5 5. fibrous connective tissue capsule 4 2 3 1 Feline Eosinophilic Granuloma Lymphoplasmacytic Stomatitis Feline gingivostomatitis (FGS)  Benign Tumor & Tumor like masses Gingival hyperplasia Epulis Papilloma (wart)  Malignant Tumor Squamous cell carcinoma Malignant melanoma Fibrosarcoma TEETH  Anomalies  Prognathia (protrusion of mandible)  Brachygnathia (short mandible) Sequel: malocclusion Enamel dysplasia  Canine distemper in puppies  BVD intra-uterine infection  Attrition & Abnormal wear Sequel:  Dental infection  Dental trauma wave mouth  Caries Acid demineralization of tooth and enzymatic digestion of dental organic matrix followed by inflammation Dental plaque (bacterial film + food + organic matrix) Dental calculus or tartar (mineralized plaque) Sequelae: Loss of tooth Alveolar osteomyelitis Tooth abscess Pulpitis Bacteremia ESOPHAGUS  choke the esophagus is blocked by foreign material , usually by food Sequelae:  Stenosis  Rupture  Perforation  Bloat  esophagitis 1- Reflux esophagitis: due to repeated gastric acid reflux 2- Ulcerative esophagitis: BVD, cows Bovine popular stomatitis 3- Parasitic: Sarcocystosis ( Cow) Spirocerca lupi (Dog)  Megaesophagus Congenital form Acquired form