Part 5: Gastrointestinal Tract Flashcards
What binds oesophagus to diaphragm?
Phreno-oesophageal ligaments (firmly bound)
What is the surface marking of the oesophagus projecting through diaphragm?
7th CC, thumbs breadth to left of sternum and level with T10
The posterior oesophagus is said to scarcely possess a serous coat why?
Posterior oesophagus is much short than anterior due to slope of diaphragm and stomach. Fold of peritoneum is not firmly attached due to the shortness of abdominal oesophagus and also allows elongation of oesophagus in movement
What are the different parts to the stomach?
Cardia (where oesophagus enters) Fundus (above level of cardia) Body (fundus to angular notch) Pylorus (angular notch to gastroduodenal junction Greater and lesser curvatures
How is the stomach fixed to abdomen?
Entire stomach is within peritoneum. Fixed at pylorus and cardia, relatively mobile in middle to allow for distension
What is the blood supply of the stomach?
L + R gastric
L + R gastroepiploic
Short gastric
What is the venous drainage of stomach?
Same as arterial
L + R gastric veins
L + R gastroepiploic veins
Short gastric vein
Venous drainage into portal vein, SMA or splenic vein
1 vein without arterial companion is prepyloric vein which overlies pylorus and drains to portal vein
What is the lymph drainage of the stomach?
Lymphoid follicles in mucosa to outlying nodes to coeliac nodes to cisterna chyli
What is the nerve supply to the stomach?
Sympathetic fibres run with arteries
Parasympathetic control motility and secretion and come from anterior and posterior vagal trunk. Anterior trunk gives hepatic branch and posterior branch gives coeliac branch to coeliac ganglion
The stomach has an extra muscle layer, what is it?
Innermost oblique muscle.
Fibres loop over fundus, pass in oblique direction to axis of organ, lie vertical in erect trunk providing gravitational support
What is the stomach mucosa?
Parietal (acid secreting cells) in body
Pyloric type G cells in pylorus (gastrin secreting)
What is the shape of the duodenum?
C-shaped around head of pancreas
What are the parts of duodenum?
1st (superior): 2”. L1. Runs upwards and backwards.
2nd (descending): 3”. R L2. Curves downwards over hilum of R kidney. Bile duct on posteriormedial wall. Lies in both supra and infracolic compartments (crossed by transverse mesocolon)
3rd (Horizontal): 4” L3. R to L. Lies on aorta at commencement IMA. Crossed by bowel mesentery (in both L + R infracolic spaces)
4th (ascending): 1”. Lt of L2. ascends to L of aorta on the L psoas which fixes DJ flexure
What are the lengths of the duodenum parts?
2,3,4 and 1 inches respectively
What supports the DJ flexure?
Suspensory muscle of the diaphragm (muscle/ligament of Trietz)
What is the mucosa of the duodenum?
Plicae circularis
Apart from 1st portion which is smooth (duodenal cap on barium)
What is the blood supply of the duodenum?
Superior and inferior pancreaticoduodenal arteries
1st part may recieve supply from heaptic, CH, GD, sup PD R gastric or R GE
Where does the jejunum begin?
DJ flexure, jejunum is defined as having mesentery where as duodenum is retroperitoneal
How can one differentiate between ileum and jejunum?
Jejunum is wider bore, thicker wall when palpated with long straight arteries in mesentery.
Ileum is narrower with thinner wall. Straight arteries of arcade are normally shorted with more fat in mesentery. Also Peyer’s patches can often be seen on ileum.
How long is the jejunum and ileum?
4-6 metres of which jejunum is 2/5ths
What is the blood supply for jejunum and ileum?
Arterial arcade arising from SMA with ileocolic contribution near terminal ileum
What are the bounds of the caecum?
Below ileocecal junction to appendix, blind pouch
What are the tineae coli?
Longitudinal muscle of large bowel form 3 flat bands, one anterior, one posteromedial and one posterolateral.
Converge on appendix
What is the ileocecal recess?
Recess between fold of terminal ileum mesentery and ant wall of caecum. Can be site of internal hernia
What is the commonest position of appendix?
Retrocolic in operations but thought to be retroileal in health
What supplies appendix?
Mesoappendix - appendicular artery (often double)
What are appendices epiploicae?
Bulbous pouches of peritoneum distended with fat projecting through serous coat of large bowel. When mucous membranes herniate through these vascular perforations it is known as diverticulosis
What are the approximate lenghts of different parts of colon?
Ascending: 15cm
Transverse: 45cm
Descending: 30cm
Sigmoid: 45cm
Describe the mesentery attachment to sigmoid colon
Hinged on mesentery but not completely fused - forms a A base with diverging limbs. Apex is at bifurcation of common artery. Lateral limb attached to external iliac 1/2 down to inguinal ligament
Medial extends to midline at S3. Mesentery fans out from 10cm base to a 40cm border with sigmoid
Which part of bowel has most extensive appendices epiploicae and is therefore most likely to get diverticulosis?
Sigmoid colon
