GI Flashcards
In which section of the GI tract is the appendix located?
Caecum
What is the major function of the colon?
Water absorption- although most already absorbed by SI
Longest section of GI tract?
ileum
Where in the GI tract are the majority of enzymes released?
From pancreas into duodenum
Where do parasympathetic pre-ganglionic fibres synapse in the gut?
Visceral wall
Cranio-sacral outflow refers to which part of the nerve supply to the gut?
Parasympathetic nervous system
What anatomical structure lies at the midpoint of the inguinal ligament?
Deep inguinal ring
What course does a DIRECT inguinal hernia take as it leaves the abdomen?
Passes through a weakness in Hesselbach’s triangle
What is the location of the linea alba?
Vertical in midline from xyphoid process to pubic symphysis
Posterior surface of rectus abdominus muscles are in contact with what structure below the arcuate line?
Transversalis fascia
What type of hernia can be precipitated by a weakened conjoint tendon?
Direct inguinal hernia
Which part of the developing gut tube has a ventral mesentry?
Foregut
How does the stomach physically disrupt food?
Muscular contractions of the ANTRUM
Which gastric secretion is part of the innate immune system?
HCl
Give a hormone involved in paracrine control of gastric acid secretions
Histamine
What causes the ‘alkaline tide’ following a meal?
Movement of HCO3 across basolateral membrane
How do NSAIDs promote epithelial damage?
Reduce gastric prostaglandin synthesis
Name an organ with blood supply from midgut and foregut
Pancreas
Which fold of peritoneum connects liver to stomach?
Lesser Omentum
What happens to bicarb conc in greater flow rates of saliva?
Increases
What consequence of chronic reflux diseases causes dysphagia?
Formation of fibrous strictures in lower oesophagus
What type of chronic gastritis can cause megaloblastic anaemia?
Autoimmune
How does H-Pylori survive acidic conditions of stomach?
Produces urease- converts urea in stomach into ammonia and CO2- ammonia forms a basic solution that raises the pH around the bacteria
What is the pain associated with gallstones called?
Biliary colic
- gallbladder has to contract harder to release bile, pain comes from contraction against stone
- not a true colic as pain does not disappear between contractions
Why does pain from gallstones come on about an hour after eating?
This is the time it takes for ingested material to be released by the stomach into the duodenum (1).
• In the duodenum the presence of acid, amino acids and fatty acids stimulates the release of cholecystokinin (1)
• Cholecystokinin then stimulates gallbladder contraction which causes pain (1) (contracting against a
blockage)
Several weeks after gallstone presentation- worsening abdominal pain, fever and RUQ tenderness. What is the explanation?
A gallstone has now probably lodged in her cystic duct and is causing cholecystitis.
The walls of the gallbladder are inflamed and oedematous and secondary infection can also occur due to bacterial proliferation.
State the potential complications of a stone lodging in:
i) Proximal CBD (2x marks
(ii) Distal CBD (2x marks)
(i)
• Cholangitis (infection of the biliary tree). (1)
• Post hepatic jaundice (can occur due to blockage bile
flow from the Liver/gallbladder to the duodenum). (1)
(ii) • Acute pancreatitis (1) (A stone lodging near the sphincter of oddi can block the major pancreatic duct. This can damage the pancreatic acinar cells due to an increased back pressure.
• Post hepatic jaundice (can occur due to
blockage bile flow from the
Liver/gallbladder to the duodenum). (1)
Following chronic alcohol intake the liver can enlarge (hepatomegaly).
(i) Name the underlying change that has caused liver enlargement
(ii) briefly describe two mechanisms that lead to the process you have named in (i)
(i) Steatosis
(ii) A byproduct of alcohol metabolism is NADH which inhibits lipid breakdown (and/or promotes lipid synthesis)
• Ethanol inhibits the formation and secretion of lipoproteins (so lipids accumulate in the liver)
Briefly describe why chronic alcohol misuse can lead to malnutrition and vitamin deficiencies
• Alcohol related chronic gastritis (impaired
digestion/release of IF)
• Pancreatitis (impaired release of digestive enzymes)
• Intestinal mucosal damage (impaired
absorption/digestion)
• Intake of alcohol replacing calories from diet
An alcoholic patient undergoes an emergency endoscopy which visualises oesophageal varices - an example of a porto-systemic anastomosis.
Briefly explain the most likely processes that have led to the formation of oesophageal varices in this patient
• Chronic alcohol abuse has led to cirrhosis (fibrotic
liver changes)
• Cirrhosis has led to portal hypertension (as portal
vein drains through liver)
• Portal hypertension has created a back pressure on
veins draining through liver, including oesophageal
veins
• Oesophageal veins form the portal section of the
porto-systemic anastomosis in the oesophagus
responsible for varices
Give areas of the body where porto-systemic anastomoses exist other than oesophageal varices
- (upper) Anal canal
• Umbilical region (forms the so called caput medusa appearance)
• Bare area of liver
• Retoperitoneum