The Gastrointestinal System - Super mesenteric artery

Question 1

What does the super mesenteric artery arise from?

Where does it move?

Answer 1

• The superior mesenteric artery arises from the aorta at L1 vertebrae level.
• It moves between the layers of the mesentery, splitting into approximately 20 branches.
• These branches anastomose to form loops, called arcades. From the arcades, long and straight arteries arise, called vasa recta.

Question 2

What does the mesentery attach to?

What part of the mesentery attaches to the duodenum and ileum?

Answer 2

• The attachment of the mesentery to the posterior abdominal wall is known as the root of the mesentery.
• The two sections of the mesentery are one proximal (jejunum) and the other distal (ileum). Examine the pattern of the arteries closely (the arterial arcades).

Question 3

• Can you see a difference? Examine both sections. Are they the same diameter?
• Open both sections of the small intestine and look at the internal surface (mucosa). How do they differ?

Answer 3

On image pg 10

• A mesentery is a double layer of peritoneum which attaches an abdominal organ to the posterior abdominal wall and allows the passage of blood vessels, nerves and lymphatics to and from the organ.
• Follow the ileum to its termination at the ileocaecal junction.