1.2 Endoscopic Anatomy Flashcards
What can you visualise with aaa nasendoscopy?
Nose, mouth, pharynx
At which spinal level may you see indentation of the left main bronchus during an OGD?
T5
What does the oesophagogastric mucosal junction look like?
Pale pink squamous oesophageal mucosa abuts dark red gastric mucosa
What is the blood supply of the upper 2/3 of the oesophagus?
Inferior thyroid artery and the aortic branches
What is the blood supply of the lower 1/3 of the oesophagus?
Left gastric branch of coeliac trunk and left inferior phrenic artery
What does the oesophagus have mixed venous drainage into?
The portal system via the left gastric vein and into the systemic circulation via the azygous begin
What condition predisposes you to oesophageal varicose?
Portal hypertension
Which mechanisms reduce reflux?
LOS
Acute angle of entry of oesophagus into stomach = valve like effect
Mucosal folds at oesophagogastric junction act as a valve
Right crus of diaphragm pinches
Positive intra-abdominal pressure compresses the walls of the intra abdominal oesophagus
What is the stomach divided into?
Cardia
Fund us
Body
Pyloric antrum
What is the pyloric sphincter?
Muscular thickening of the distal pylorus
What does the pyloric sphincter do?
Controls passage of stomach contents into the duodenum
What are the folds of the stomach called?
Rugae
Which artery may be damaged by a posterior duodenual ulcer?
Gastroduodenal artery
Where does the transition from embryonic foregut to midgut occur in the GI tract?
At the duodenal papilla
What is the blood supply to the duodenum?
Coeliac trunk
Superior mesenteric artery
What does ulceration in second part of duodenum suggest?
Pancreatic disease
Zollinger-Ellison syndrome
Where does the biliary tree start?
In the liver from the intra-hepatic ducts which form the left and right hepatic ducts
At what point do the left and right hepatic ducts merge and what do they become?
At the porta hepatis
To become the common hepatic duct
Where does the cystic duct come from?
The gall bladder
What arises once the cystic duct joins the common hepatic duct?
Common bile duct
Why does a carcinoma at the head of the pancreas cause obstructive jaundice?
Obstructs the common bile duct
What does PAINFUL obstructive jaundice suggest?
Gallstone
Why does the jejunum have a thicker wall than the ileum?
Increased number, larger and taller plicae circulares
Why is the jejunum a deeper red than the ileum?
Greater blood supple
What happens the the jejunal wall in coeliac disease?
Villi and crypts atrophy
Where may a Meckels diverticulum be found?
Distal ileum
What is a meckels diverticulum a remnant of?
The embryonic vitellointestinal duct
Where can the largest number of peyers patches be found?
Ileum
Describe the muscle layers in the colon?
3 longitudinal bands of muscle along its length which form taenia coli
What does the iliocaecal valve do?
Prevents backflow of colonic contents during peristalsis
Where does the caecum lie?
Right iliac fossa
What are appendices epiplociae?
Fat filled peritoneal tags on outer surface
Why are sigmoid volvulous fairly common?
Sigmoid colon is long
Has a loose mesenteric attachment
What is the upper part of the anal canal derived from?
Hindgut
What epithelium can be found in the upper anal canal?
Columnar epithelium (mucosa)
What epithelium can be found in the lower anal canal?
Stratified squamous epithelium
Which artery supplies the upper rectum?
Inferior mesenteric artery
What artery supplies the lower rectum?
Inferior rectal artery
Why is upper rectal pain dull and poorly located?
Nerve supply is from the visceral pelvic splanchnic nerves
Why is pain in the lower rectum sharp?
Supplies by the inferior rectal nerve which is a somatic nerve from the pudenal nerve
What are haemorrhoids?
Dilatations of the superior rectal veins
