GI Tract: Esophagus and Stomach Flashcards
Achalasia is
- reduced vagal tone of the lower esophageal sphincter (LES), causing things to have difficulty getting into the stomach.
- Cause dysphagia.
- Due to neuronal loss in the lower regions of the enteric plexus (lose inhibition), it is tonocally inactivated and the sphincter stay closed.
Esophageal varices:
- Varicose veins bulging into the lumen.
- Due to increase pressure in the portal venous system
- Are very fragile, can easily rupture–>hemmorhage
Esophagitis:
-Infection occurring due to immunocompromised or decreased esophageal motility (innervation is decreased, food can get trap)
Enteric nervous system covers which regions?
- From the oesophagus to the large intestine
- Submucosal plexus and Myenteric plexus
Swallowing center is in: (part of the brain)
Medulla oblongata
Hiatus hernia:
- Is when the lower part of the stomach and initial part of the stomach moves up into the diaphragm –> form a little pouch/hernia.
- Most common cause of GastroEsophageal Reflux Disease (GERD)
Recurrent Gastroesophageal Reflux DIsease can cause:
- Injury in the lining of the eosophagus –> resulting in hyperplasia of the squamous cells –> metaplasia –>malignant transformation
- Lead to ulceration, fibrosis, stricture (narrowing)
- Can trigger esophageal spasm (interfer with swallowing)
Type of cells in the stomach:
Parietal cells (secrete HCL) Chief cells (make pepsinogen) Mucuous neck cells (secrete mucous to protect us)
Acute gastritis:
-acute inflammation due to some component such as ethanol, aspirin, which destroys the mucous and lead to erosion. (reversible)
Peptic Ulcer Disease:
- Ulcer penetrating through the superficial layer into the submucosa and muscularis in the body of the stomach or at the beginning of the duodenum (can go down the serosa in chronic ulcers)
- cause by an imbalance between acid output and mucosal defense (more acid output than mucosal)
- Cause formation of granulation tissue at the bottom and fibrosis.
3 basic strategies used to treat ulcers:
- Neutralize the acid with antacids
- Blocking histamine
- Blocking the acid pump
Helicobacter Pylori is a bacteria able to live in the stomach environment and is one of the principle cause of ulcer. This bacteria use multiple mechanisms to survive in the pH of the stomach and to damage the stomach which are:
- Secrete enzyme (Urease) neutralizing the gastric acid
- Had Flagella for rotation and to burrow through the mucous
- Secrete exotoxins and enzyme dissolving the mucous
- Adhere tot he cells in our stomach via proteins on the cell surface
- Had Type IV secretion system, an injection system to inject damaging compounds and proteins right into the host cell in the stomach.
The 3 major ways the Helico Pylori destroys the epithelium of the stomach:
- Had neutrophil-activating protein (HP-NAP) that triggers intensive inflammation and injuries
- The Cag protein will be injected directly in the cell to kil it
- The VacA, a cytotoxin that forms pores inside the cell and will trigger apoptosis
Cytotoxin VacA features:
- Forms pores inside the cell and will trigger apoptosis
- Forms ion channels that will get endocytosed into the endosome and end up altering the endosome by fill up it with water and end up forming a large vacuole inside the cell.
Pyloric stenosis:
- difficulty for things to get through this region due to thickened region of muscle around the pylorus
- Classical symptom is projectile vomiting
