GI Flashcards
approximately how long is the oesophagus?
25cm
from which vertebral levels does the oesophagus extend?
C6-T11
what two parts can the oesophagus be divided into?
thoracic and abdominal
what level does the oesophagus pierce the diaphragm?
T10
which ligament connects the oesophagus to the border of the oesophageal hiatus?
the phrenicoesophageal ligament
what are the three muscular layers of the oesophagus and are they voluntary or smooth muscle?
-superior third- voluntary striated -middle third- voluntary striated and smooth muscle -inferior third- smooth muscle
what level does the oesophagus enter the stomach?
T11
which of the oesophageal sphincters is anatomical?
upper
which of the oesophageal sphincters is physiological?
lower
what forces cause the lower oesophageal sphincter?
-acute angle -positive intra abdominal pressure -folds of the mucosa present -the right crus of the diaphragm has a ‘pinch cock’ effect
what arteries supply the thoracic part of the oesophagus?
-branches of the thoracic aorta and the inferior thyroid arteries
what veins supply the thoracic part of the oesophagus?
azygous veins and the inferior thyroid veins
what arteries supply the abdominal section of the oesophagus?
left gastric artery and left inferior phrenic nerve.
in what two ways is the venous drainage of the abdominal part of the oesophagus supplied?
-to the portal circulation via the left gastric vein -the the systemic circulation via the azygous vein
what is the clinical significance of the different venous drainage of the oesophagus.
it drains into the portal circulation, so when the intra hepatic pressure increases (like in liver failure) the veins can be damaged- oesophageal varicies
what is barrettes’ oesophagus?
metaplasia of lower oesophagus squamous epithelia to gastric columnar epithelia. Usually due to chronic acid exposure.
what are the two major types of oesophageal carcinoma?
-squamous cell carcinoma -adenocarcinoma
where is it most likely to find an adenocarcinoma of the oesophagus? (except from the oesophagus smart ass)
-inferior 1/3 -associated with barrettes’ oesophagus
where is it most likely to find a squamous cell carcinoma of the oesophagus?
any level !
between which vertebral levels does the stomach extend?
T7-L3
what are the 4 main sections of the stomach?
-cardia -fundus -body -pylorus
what arteries supply the greater curvature of the stomach?
the short gastric arteries, the right and left gesture-omental arteries.
Which ligament attaches to the lesser curvature of the stomach and what travels within it?
hepatogastric ligament with the hepatic triad within.
which arteries supply the lesser curvature of the stomach?
left gastric artery and right gastric branch of the hepatic artery.
where is the pyloric sphincter located?
between the pylorus and duodenum
what is the role of the pyloric sphincter?
controls the exit of chyme from the stomach
is the pyloric sphincter an anatomical or physiological sphincter?
anatomical
what characteristic of the pyloric sphincter makes sure food stays in the stomach for a suitable amount of time?
the pylorus in normally tonically contracted so the orifice is small
why is the greater omentum often called the policeman of the abdomen?
it contains lymph nodes and macrophages which help combat infections and wall off infections in the abdomen.
what is the main function of the lesser omentum?
attach the stomach and duodenum to the liver
what do the omen separate the abdomen into?
the greater and lesser sacs
through what structure do the greater and lesser sacs communicate?
the epiploic foramen
which arteries supply the stomach?
-right gastric -left gastric -right gastro-omental -left gastro-omental
which nerve supplies the parasympathetic innervation of the stomach?
posterior vagal trunks derived from the vagus nerve
which nerve supplies the sympathetic innervation of the stomach?
T6-T9 spinal cord segment
what six cells are found in the stomach and what do they secrete?
-mucous neck cells-mucus -parietal cells-HCL and intrinsic factor -enterochromaffin cells-histamine -chief cells- pepsinogen and lipase -D cells- somatostatin -G cells- Gastrin
what are the effects of gastrin?
-stimulates parietal cells to secrete HCL -stimulates chief cells to secrete pepsinogen -contracts the lower oesophageal sphincter -increases stomach motility -relaxes pyloric sphincter -digestion
What is GORD?
-Gastro-osophageal reflux disease -gastric acid and food moves past the lower oesophageal sphincter into the oesophagus
what are the common symptoms of GORD?
-chronic heartburn -dysphagia -unpleasant sour taste in the mouth
what are the three main causes of reflux disease?
-dysfunction of the lower oesophageal sphincter -delayed gastric emptying -hiatal hernia
what are the methods of treatment of GORD?
-lifestyle changes -medication -surgery as a last resort
give a brief description of a hiatus hernia.
when part of the stomach protrudes into he chest through the oesophageal hiatus in the diaphragm.
what are the two types of hiatus hernia?
-sliding hernia- lower oesophageal sphincter slides superiorly -rolling hernia- the lower oesophageal sphincter remains in place, but a part of the stomach herniates into the chest next it
where do the four sections of the duodenum lie in relation to the vertebrae?
-superior-L1 -descending-L1-L3 -inferior-L3 -Ascending-L3-L2
which part of the duodenum are duodenal ulcers most common?
Superior
what marks the descending duodenum?
the major duodenal papilla and sphincter of oddi
which part of the duodenum crosses the aorta and vena cava?
inferior
what vessel passes anteriorly to the front of the inferior duodenum?
SMA
which muscle decreases the angle of the duodenojunal flexure and thus helps movement of intestinal contents into the jejunum?
suspensory muscle of the duodenum
what forms the ilioceacal valve?
ileum invaginate into the ceacum
which of the jejunum and ileum have longer vasa recta?
jejunum
which of the jejunum and ileum have more arcades?
ileum
what are the two most common causes of duodenal ulcers?
-helicobacter pylori infection -chronic NSAIDs
which two arteries supply the duodenum?
-initial part- gasproduodenal artery -distal to the duodenal papilla- inferior pancreaticoduodenal
what does the change in blood supply of the duodenum signify?
the change from the embryological foregut to midgut
which artery supplies the jejunum and ileum?
SMA
which vain drains the jejunum and ileum?
superior mesenteric vein
which vein combines with the SMV to form the hepatic portal vein?
the splenic vein
what are the four sections that the large intestine can be split into?
-cecum and appendix -colon -rectum -anal canal
what are the three tenia coli which can be located on the large bowel?
-free tenia -mesenteric tenia -omental tenia
what is the action of the tenia coli?
contract to shorten the wall of the bowel, producing sacculations known as haustra.
what artery supplies the caecum?
ileocolic artey
which vein drains the caecum?
ileocolic artery
what is the appendix?
acute inflammation of the appendix?
where in the abdomen is most tender in appendicitis?
-McBurneys point -1/3 of the distance from the right anterior superior iliac spine to the umbilicus.
what are the four parts of the colon?
ascending, transverse, descending and sigmoid
what is the change of angle in the colon in the RUQ called?
hepatic flexure (right colic flexure)
what is the change of angle in the colon in the LUQ called?
splenic flexure (left colic flexure)
what are the spaces lateral to and between the ascending and descending colon and the abdominal called?
the left and right parabolic gutters
what is the marginal artery of the colon?
form anastomosis between the superior and inferior mesenteric arteries
what is the arterial supply and venous drainage of the transverse colon?
-artery-ileocolic and right colic (branches of the SMA) -vein-ileocolic and right colic (branches of the SMV)