Basic Structures, Processes And Endoscopy Flashcards
Name the 3 pairs of salivary glands
Parotid
Sublingual
Submandibular
What are the 4 layers of the gut wall?
Mucosa
Submucosa
Muscularis externae
Serosa
What are Peyer’s patches?
Aggregations of lymphocytes often present in the lamina propria
What constituents the mucosa?
Epithelium
Lamina propria
Muscularis mucosa
What is the submucosa?
A layer of connective tissue bearing glands, arteries, veins and nerves
What are the 2 layers of muscularis externae?
Outer = longitudinal Inner = circular
What is the of IgA?
Secreted in saliva to bind to bacteria and prevent them getting though the epithelium
Describe the innervation to the oesophagus
Myenteric plexus = between the 2 muscle layers
Submucosal plexus = between the muscularis externae and the submucosa
What are the 3 layers of muscle in the stomach called?
Circular
Longitudinal
Oblique
What are Brunner’s glands?
Glands that secrete bicarbonate rich mucus to neutralise the acidic chyme from the stomach
What are plicae circulares?
Circular folds of mucosa and submucosa that project into the lumen of the jejunum to increase SA
What does the duodenum absorb?
Iron
What does the jejunum absorb?
Most sugars, amino acids and fatty acids
What does the ileum absorb?
Vitamin B12, bile acids and remaining nutrients
Where do GI contents await expulsion?
Colon
Where do you find most of the GI bacteria?
Colon
What type of bacteria are found in the colon?
99% anaerobic
How much do we ingest per day?
Approx 1 kg
How much saliva do we produce a day?
Approx 1.5 litres
How much does the stomach secrete a day?
Approx 2.5 litres
Which absorbs more water, the small or large intestine?
Small intestine
How much faeces do we produce a day?
Approx 150g
Which cells release gastrin?
G cells in the stomach
What is secretin?
Produced by the duodenum to promote bicarbonate production in the pancreas
What does ERCP stand for?
Endoscopic retrograde cholangiography and pancreatography
What is a hiatus hernia of the oesophagus?
Weakness in the oesophageal hiatus allows the cardia and fundus of the stomach to herniate into the thorax
What is the blood supply to the upper 2/3 of the oesophagus?
Inferior thyroid artery
Aortic branches
Drains = inferior thyroid vein and azygous branches
What is the blood supply to the lower 1/3 oesophagus?
Left gastric branch of coeliac trunk
Left inferior phrenic artery
Drains = left gastric vein (portal system)
Define achalasia
A condition in which the muscles of the lower oesophagus fail to relax, preventing food passing into the stomach
What mechanisms do we have to reduce reflux?
Acute angle of entry of oesophagus into stomach (valve like)
Mucosal folds at oesophagogastric jucntion act as a valve
Right crus of the diaphragm acts as a ‘pinch-cock’
Positive intra-abdominal pressure compresses the walls of the abdominal oesophagus
What is the pyloric sphincter?
The muscular sphincter of the stomach the controls the passage of stomach contents into the duodenum
Where is gastric ulceration often found?
Lesser curve at the angulus
What ligament supports the duodenojejunal flexure?
Ligament of Treitz
At what vertebral level does the duodenum commence?
L1
How many divisions of the duodenum are there?
4
Describe the superior portion of the duodenum
5cm Intraperitoneal Overlapped by liver and gall bladder Gall stones may cause erosion - can lead to fistulae here Ulcers common
Describe the descending part of the duodenum
Retroperitoneal 7.5cm Curves round head of pancreas Major duodenal papilla half way along (sphincter of Oddi here) Transition from foregut to midgut
What is Zollinger-Ellison Syndrome?
A gastrin secretion tumour of the pancreas that stimulates acid secreting cells of the stomach
Describe the horizontal part of the duodenum
10cm
Crosses aorta at L2/3
Can lead to aorta-duodenal fistulae (rare)
Describe the ascending portion of the duodenum
2.5cm
Duodenojejunal flexure
Retroperitoneal
What ducts form the common hepatic duct?
Left and right hepatic ducts
Which ducts form the common bile duct?
Cystic duct from gall bladder and common hepatic duct
What is the epiploic foreman of Winslow?
Foramen from the greater to the lesser sacs of peritoneum
How do we control hepatic haemorrhage?
Pringle manoeuvre - occlude the portal vein and hepatic artery by applying pressure to the free edge of the lesser sac
What is the anatomical difference in coeliac disease?
The jejunum crypts and villi atrophy
Why does the colonic wall have haustrations?
The lengths of muscle are shorter than the colon itself so bunch the colonic wall
Why is there a valve at the ileocaecal junction?
To prevent backflow of colonic contents
Where is the appendix?
Arises from posterior-medial aspect of the caecum
Approx 3 cm below the ileocaecal valve
Why does the sigmoid colon often twist?
It’s very long
Has a loose mesenteric attachment
What percentage of colon cancers are found in the rectum?
50%
What are haemorrhoids?
Dilatations of superior rectal veins
What distinguishes whether haemorrhoids are painful or not?
Origin:
Above pectinate line = painless
Below pectinate line = painful (extremely)
Which pair of glands produces the most saliva?
Submandibular
What is kallkrein?
An enzyme that helps produce bradykinin to help vasodilation - allow blood flow to get to glands
