53. GI anatomy part 3 Flashcards
What is the most common position of the appendix?
Pelvic (5 o’clock)- google
retrocecal (11 o’clock)- teach me anatomy
How is the appendix supplied?
How is the appendix lymphatically drained?
Appendicular artery
Ileoceacal nodes
What is the function of the cecum?
Reservoir for chyme
How is the cecum supplied?
The ileocolic artery
What is the hepatic flexure?
Marks the end of the ascending and beginning of transverse colon.
What is the splenic flexure?
Where the transverse colon stops and the descending colon begins. Attached to the diaphragm by the phrenicocolic ligament
What distinctive features differentiate the large colon from the rest of the GI tract?
Omental appendices- small pouches of perinternum filled with fat
Teniae coli- three strips of muscle that shorten the wall of the bowel
Haustra- segmented structures formed when the haustra contract
How is the ascending colon supplied by arteries?
Supplied by the superior mesenteric artery:
ileocolic and right colic arteries
How is the transverse colon supplied arterially?
Right colic artery (superior mesenteric artery)
Middle colic artery (superior mesenteric artery)
Left colic artery (inferior mesenteric artery)
How is the descending colon supplied?
Left colic artery (branch of superior mesenteric artery)
Why is the marginal artery of drummond important?
Provides collateral supply to the colon incase of occlusion or stenosis.
How is the rectum supplied/drained?
Superior rectal artery/vein
Middle rectal artery/vein
Inferior rectal artery/vein
What structure of the anus relaxes to promote feacal loading?
The ampulla
Discuss the histology of the anal canal?
Contains a pectinate line where the anus is divided in tow
Upper part is keratinised squamous epithelium
Lower part is non keratinised stratified squamous epithelium
What is the function of the liver?
Glycogen storage
Detoxification
production of clotting factors
Bile synthesis
What are the major ligaments of the liver (4)
Falciform Ligament- divides liver into left and right
Coronary ligament (anterior and posterior fold)- demarcates bare area of liver. Liver to diaphragm
Triangular ligament (left and right)- edges of liver to diaphragm
Lesser Omentum- combination of hepatoduodenal ligament and hepogastric ligament
Where is peritoneal fluid most likely to collect in a supine patient
Morison’s pouch
potential space between the visceral surface of the liver and the right kidney
deepest part of peritoneal cavity
Describe the four lobes of the liver?
Right and left lobe separated by the falciform ligament
Caudate lobe- lies on the superior aspecty of the visceral surface (underside) beside the IVC.
Caudate- Lies on inferior aspect of visceral surface,lies between the gallbladder and ligamentum teres
What separates the caudate and quadate lobe?
known as the porta hepatis. It transmits all the vessels, nerves and ducts entering or leaving the liver with the exception of the hepatic veins
Describe the arrangement of the liver microscopically
hexagonal arrangement of hepatocytes with a central vein in the middle. At the periphery of the hexagon are the portal triad (arteriole, venule and bile duct)
Sinusoids act as fenestrated capillaries to allow for filtration
Explain the blood supply to the liver?
hepatic artery (25%)
Hepatic portal vein (75%)- contains nutrients and partially deoxygenated blood
What are the indications for a liver biopsy
Abnormal LFT’s
Liver Malignancy
Hep C
Following liver trasnplant
What are the two types of liver biopsy?
Subcostal approach
Transvenous biopsy (clotting disorder)
