GI 1 - Basics + Common diseases Flashcards
What is the approx. length of the oesophagus?
~ 25 cm
What are the 4 mechanisms which prevent reflux from the lower oesophageal sphincter?
1) Right crus of diaphragm acts as a pinch-cock
2) Acute angle from oesophagus to stomach
3) Mucosal folds of oesophagogastric junction acts as a valve
4) Abdominal pressure is higher than thoracic pressure
Name the 5 regions of the stomach:
- Cardia
- Fundus
- Body
- Antrum
- Pylorus
Behind which laryngeal cartilage does the upper oesophageal sphincter lie?
Cricoid cartilage
In which part of the GI tract is the majority of fluid absorbed?
Small intestine
Which parts of the GI tract are not controlled by autonomic nerves?
- Mouth
- 1st 1/3rd of Oesophagus
- External anal sphincter
Name the 2 main nerve plexuses of the enteric nervous system, which control GI motility:
1) Auerbach’s myenteric plexus
2) Meissner’s submucosal plexus
Where is Auerbach’s myenteric plexus located?
Between the inner circular and outer longitudinal layers of muscularis externa, surrounding the GI tract
Where is Meissner’s submucosal plexus located?
Beneath muscularis externa, on top of the submucosa, surrounding the GI tract
Name the nerve plexus which lies between the inner circular and outer longitudinal layers of muscularis externa, surrounding the GI tract:
Auerbach’s myenteric plexus
Name the nerve plexus which lies beneath muscularis externa, on top of the submucosa, surrounding the GI tract:
Meissner’s submucosal plexus
Name the common complications of chronic acid reflux:
- Oesophagitis
- Barrett’s oesophagus
- Oesophageal cancer
What causes Barrett’s oesophagus usually?
Chronic acid reflux
Describe the pathology of Barrett’s oesophagus:
Metaplasia of normal non-keratinised stratified squamous epithelia of lower oesophagus, into simple columnar gastric epithelium
Name the 2 most common types of oesophageal cancer:
- Squamous cell carcinoma
- Adenocarcinoma
What are the main risk factors predisposing someone to oesophageal cancer?
- Male sex
- Age
- Smoking
- Heavy drinking
- Obesity
- Acid reflux
What are oesophageal varices?
Abnormally enlarged veins in oesophagus, prone to rupturing and bleeding
What causes oesophageal varices?
Portal hypertension, commonly dues to:
- Liver cirrhosis
- Thrombosis
- Schistosomiasis
List some sites of portosystemic anastamoses:
- Lower oesophagus
- Anal canal
- Umbilical area
Portal hypertension can result in caput medusae. What is this?
Abnormally enlarged and dilated veins radiating from the umbilicus across the abdomen.
What are the 2 main types of dysphagia?
1) Oropharyngeal dysphagia
2) Oesophageal dysphagia
What is dysphagia?
Difficulty swallowing
What is oropharyngeal dysphagia?
Difficulty swallowing - cannot initiate the swallow
What is oesophageal dysphagia?
Food sticking in the oesophagus AFTER swallowing
List some common causes of dysphagia:
- Stroke
- GERD
- Dementia
- Benign/malignant tumours
- Scar tissue
What is odynophagia?
Painful swallowing
What is achalasia?
Dysphagia in which the lower oesophageal sphincter doesn’t relax properly, so food cannot pass into the stomach
How will dysphagia caused by a malignancy often present?
- Coughing
- Hoarse voice
- Haematemesis
- Acid reflux
- Progressively harder to swallow
What are the common causes of peptic ulceration?
- Helicobacter pylori
- Aspirin/NSAIDs/Steroids (chronic use)
- Stress
- Alcohol
- Smoking
How does the chronic use of aspirin/NSAIDs/steroids lead to peptic ulceration?
- These drugs reduce prostaglandin secretion
- Prostaglandins maintain the gastric mucosal defence system, by regulating bicarbonate and mucous secretion, and inhibiting acid secretion
