GB 7. Superior Mesenteric Vessels, Bowels and Pancreas Flashcards
What vertebral level does the coeliac artery branch off from the abdominal aorta?
T12
What vertebral level does the superior mesenteric artery branch off from the abdominal aorta?
L1
What vertebral level does the inferior mesenteric artery branch off from the abdominal aorta?
L3
What are the 4 parts of the pancreas?
[1] Head - the Uncinate Process is part of the head [2] Neck [3] Body [4] Tail
Where is the pancreas located and how is it oriented?
The pancreas is mostly retroperitoneal except for the tail - the tail lies in the splenorenal ligament/lienorenal ligament
It runs from the duodenum to spleen
What type of gland is the pancreas?
It is an exocrine gland (secretes substances - enzymes - into the ducts) AND an endocrine gland!
What are the 3 main enzymes that the pancreas excretes into the exocrine ducts?
[1] Amylase
[2] Trypsin
[3] Lipase
What are the main substances/hormones that the pancreas secretes into the endocrine glands?
[1] Insulin
[2] Glucagon
The common bile duct opens up into which opening in the duodenum?
the Common Bile Duct opens into the Major Duodenal Papilla
What is the name for the pancreatic duct that is located in the body and tail of the pancreas?
Duct of Wirsung
What is the name of the duct that opens into the Minor Duodenal Papilla?
Duct of Santorini
What does the Duct of Santorini open up into?
Minor Duodenal Papilla
What is the Ampulla of Vater?
- is an important landmark halfway along the second part of the duodenum that marks the anatomical transition from foregut to midgut
- it is where the common bile duct and pancreatic duct combine
What is the Sphincter of Oddi?
the sphincter near the major duodenal papilla
Where is pancreatic pain felt posteriorly and anteriorly?
Posteriorly - Back
Anteriorly - Abdomen
What is pancreatitis and what can it be caused by?
Pancreatitis: the inflammation of the pancreas
- a possible cause is a pancreatic psuedocyst
If there is a cancer in the head of the pancreas, what can this lead to?
This can lead to blockage of the common bile duct
- this will lead to build up of bilirubin and yellowing of the eyes and skin
What is an example of a congenital abnormality of the pancreas?
Annular Pancreas - the head of the pancreas extends around the duodenum, constricting it and not allowing passage of food
What are the lengths of small intestine and mesentery? *hint: main idea, not numbers
Length of Small Intestine: 6 meters/24 feet
Length of Mesentery Base: 15 cm/6 inches
The mesentery is short while the small intestine is longer - kind of like a fan
Where is the jejunum and the ileum located?
Jejunum - upper left region
Ileum - lower right
What are some characteristics of the jejunum?
- thick wall
- wide lumen
- valvulae conniventes
- plicae circulares (mucosal folds - more prominent in jejunum than ileum)
What are some characteristics of the ileum?
- thinner wall
- small lumen
- mesenteric fat encroaches on bowel wall
- peyer’s patches (lymphoid tissue controls bacteria)
Compare and contrast the length of the arterial arcades and vasa recta in both the jejunum and ileum.
JEJUNUM:
Arterial Arcades: small
Vasa Recta: long
ILEUM:
Arterial Arcades: larger
Vasa Recta: small
What is the junction/valve between the ileum and caecum called?
Ileocaecal Valve
What are some characteristic features on the large intestine/colon? (e.g. muscles…)
[1] Haustrations - they give the colon its segmented appearance
[2] Taenia Coli - the longitudinal muscle of the colon
[3] Appendices Epiploicae - they are small pouches of the peritoneum that are filled with fat
What is Diverticulosis? What are some causes of it?
It is development of small sacs/out-pouchings in the wall of the colon (diverticula)
Possible Causes:
[1] due to increased pressure on weakened spots of intestinal walls (e.g. straining during constipation)
[2] may result in inflammation (diverticulitis)/rectal bleeding
What is the mesoappendix?
It is part of the mesentery connecting the ileum to the appendix.
What are the 5 different locations that the appendix may be found in?
[1] Preileal [2] Postileal [3] Pelvic [4] Subcecal [5] Retrocecal
What is the two different sensory neurons associated with the appendix and the abdominal wall?
Appendix has visceral sensory nerves
The Parietal Peritoneum has somatic sensory nerves
What is Meckel’s Diverticulum? What is it a remnant of (embryology)? What may it contain that will lead to serious conditions in the individual?
- it is an outpouching of the intestines (lower part of the small intestine)
- it is a remnant of the embryonic vitellointestinal duct (or yolk stalk)
- it may contain Ectopic Gastric Mucosa which secretes acid and causes BLEEDING from intestinal mucosa
What are the branches of the Superior Mesenteric Artery?
[1] Inferior Pancreaticduodenal Artery [2] Jejunal Arteries [3] Ileal Arteries [4] Ileocolic Arteries [5] Right Colic Artery [6] Middle Colic Artery
What are the branches of the Inferior Mesenteric Artery?
[1] Left Colic Artery
[2] Superior Rectal Artery
[3] Sigmoid Arteries
What is the Marginal Artery of Drummond?
It is the anastomoses of the terminal branches of the Superior Mesenteric Artery and Inferior Mesenteric Artery
What does the Superior Mesenteric Artery and Inferior Mesenteric Artery anastomose to create?
Marginal Artery of Drummond
What is the importance of the porto-systemic anastomoses?
The importance of portosystemic anastomoses is to provide alternative routes of circulation when there is a blockage in the liver or portal vein.
- the blood will flow through the systemic veins into the heart (even though this is dangerous too)
Where are some of the porto-systemic anastomoses? [3]
[1] Lower Esophagus
- between Left Gastric Vein and Esophageal Veins
[2] Upper Part of Anal Canal
- between Superior Rectal Vein and Middle + Inferior Rectal Veins
[3] Umbilicus
- between Paraumbilical Veins and Epigastric Veins (small)
What happens to the esophageal porto-systemic anastomosis when there is portal hypertension?
ESOPHAGEAL VARICES
- they are enlarged veins in the esophagus
- occurs when there is a problem draining blood and the systemic veins take over
- the veins can start bleeding and they become dilated
- can be fatal
What happens to the umbilicus porto-systemic anastomosis when there is portal hypertension?
CAPUT MEDUSAE
- enlarged veins in abdominal wall radiating from umbilicus (looks like varicose veins)
- due to high blood pressure in the veins when portal system is blocked
- DO THIS - SLIDE 32
At what vertebral level does the abdominal aorta split into the left and right common iliac?
L4
