Gastrointestinal Disorders Flashcards
What is the esophageal hiatus?
Hole in diaphragm where esophagus passes through thoracic cavity into the abdominal cavity
Where does majority of digestion occur?
In small intestine
What are the three components of the small intestine?
Duodenum, jejunum, ileum
What is the main job of the large intestine?
Absorption of water and electrolytes, forms a denser package to prepare to expel
What is the innermost region of the GI wall?
The mucosa, lined with epithelial cells
What lies beneath mucosa?
Sub-mucosa= home to vessels, immune cells, some glands
What is the outermost region of the GI wall?
Serosa/ adventitia= layer of connective tissue, supports and attaches to the mesentary (attaches to abdominal wall)
What is the enteric nervous system?
Located solely in the GI tract, controlled by local and autonomic nervous system stimuli–neurons regulate motility reflexes, blood flow, absorption, secretions, immune response
What is the role of IgA antibodies?
B cells–> plasma cells–> produce IgA antibodies that are secreted into lumen and keep the commensal bacteria in check
What are some key immune cells involved in the GI tract?
Dendritic cells extend into the lumen, take up molecules and present them to T cells (regulatory T cells)
What are some of the important roles of the liver?
Detoxification, storage of nutrients, production of bile salts, and production of plasma proteins
What is the main role of the gallbladder?
Stores bile salts, secretes them into the duodenum
What is the role of bile salts?
Emulsify fats–able to get between fat molecules, take them from globs to smaller molecules through emulsification
What is the role of acinar cells?
Produce enzymes
What is the role of duct cells?
Secrete bicarb, neutralize stomach acid, protect small intestine
How do exocrine secretions enter duodenum?
Via ampulla, shared region between gallbladder and pancreas
How are digestive enzymes synthesized?
Inactive form, have to be activated by enteropeptidase
What is the role of trypsin?
Enzyme that aids in digestion of proteins, serves to activate other proenzymes from pancreas
What are some risk factors for GERD?
Sliding hiatal hernia, obesity, smoking, alcohol, certain foods and conditions/activities that increase abdominal pressure
What is the key issue in GERD?
Lower esophageal sphincter becomes more relaxed, reduced resting pressure
Where does the LES sit in relation to the esophagus hiatus?
Just above!
What is Barrett’s esophagus?
Some individuals with GERD experience abnormal repair processes following exposure to acidic chyme, epithelium changes and squamous epithelium is replaced by metaplastic columnar epithelium and goblet cells *increases risk for esophageal adenocarcinoma
Who is chronic gastritis more likely to occur in?
Those with H.Pylori infections, autoimmune reactions, chronic use of alcohol/tobacco/NSAIDs
What is autoimmune metaplastic atrophic gastritis?
Autoimmune reaction against gastric parietal cells, autoantibodies target intrinsic factor and proton pumps (facilitate the production of HCl)
What is the role of parietal cells?
Produce hydrochloric acid and intrinsic factor
What is the role of intrinsic factor?
Protein that binds to Vit B12, helps it be absorbed within the ileum
What can autoimmune metaplastic atrophic gastritis result in?
Destruction of parietal cells= less intrinsic factor= less HCl= Vit B12 deficiency= pernicious anemia
What is pernicious anemia?
Deficiency of Vit B12–RBC’s need Vit B12 to synthesize their DNA