Midgut and Hindgut

Question 1

Midgut

• Consists of
• Contains
• Blood supply

Answer 1

• 2nd half of the duodenum, jejunum, ileum, caecum, appendix, ascending colon to 2/3rds of the way across the transverse colon
• Small and large intestine
• Branches from the superior mesenteric artery (Aorta L1)

Question 2

Hindgut

• Consists of
• Blood supply

Answer 2

• Rest of transverse colon, descending colon, sigmoid colon, rectum and anal canal
• Branches from the inferior mesenteric artery (Aorta L3)

Question 3

Jejunum and Ileum

• Proportions
• Attached to
• Arterial supply
• Venous drainage
• Lymphatics
• Nerves

Answer 3

• Jejunum makes up proximal 2/5ths and ileum makes up distal 3/5ths
• Mesentery. Fan shaped fold of peritoneum enclosing the gut tube.
• Jejunal and ileal branches of superior mesenteric artery. These form arcades. Lower ileum by parts of ileocolic artery.
• Drain into superior mesenteric veins
• Mesenteric nodes and pre-aortic nodes at L1
• ANS superior mesenteric plexus. Pain to umbilical region.

Question 4

Large intestine

• Function
• Haustra
• Appendicies epiploicae
• Teniae coli

Answer 4

• Absorbs water and electrolytes, and stores undigested material before expulsion
• Sacculations of the wall (small intestine smooth)
• Fatty tags
• Longitudinal muscle which is collected into 3 bands

Question 5

Caecum

• Opening
• Arterial supply
• Veins
• Lymph
• Nerves

Answer 5

• 2 folds forming the ileocaecal valve
• Caecal arteries from the ileocolic (superior mesenteric)
• To superior mesenteric
• To mesenteric then superior mesenteric nodes (L1)
• ANS superior mesenteric plexus

Question 6

Appendix

• Arterial supply
• Veins
• Lymph and nerves
• Pain

Answer 6

• Apendicular artery
• To posterior caecal vein
• Same as caecum
• Referred to umbilicus @T10

Question 7

Ascending Colon

• Peritoneum
• Arteries
• Veins
• Lymph
• Nerves

Answer 7

• Retroperitoneal
• Ileocolic and right colic branches of superior mesenteric
• To superior mesenteric vein
• To superior mesenteric nodes @L1
• ANS from superior mesenteric plexus

Question 8

Transverse Colon

• Arteries
• Veins
• Lymph
• Nerves

Answer 8

• Proximal 2/3 from middle colic (sup mesen) and distal 1/3 from left colic (inf mesen)
• To superior and inferior mesenteric veins
• Proximal 2/3 to superior mesenteric nodes @L1, distal 1/3 to inferior mesenteric nodes @L3.
• ANS from superior and inferior mesenteric plexuses. Vagus to proximal 2/3rds and distal 1/3 parasympathetic from pelvis

Question 9

Descending Colon

• Arteries
• Veins
• Lymph
• Nerves

Answer 9

• Left colic and sigmoid arteries
• To inferior mesenteric
• Inferior mesenteric pre-aortic nodes @L3
• Sympathetic from inferior mesenteric plexus and parasympathetic from pelvis

Question 10

Sigmoid Colon

• Arteries
• Veins
• Lymph
• Nerves
• Attachments

Answer 10

• Sigmoid branches of the inferior mesenteric artery
• To inferior mesenteric vein
• Inferior mesenteric nodes @L3 aorta
• ANS from inferior hypogastric plexus
• Attached to posterior pelvic wall by the mesocolon

Question 11

Intestinal Arteries

Answer 11

Question 12

Rectum

• Arteries
• Veins
• Lymph
• Nerves

Answer 12

• Superior, middle and inferior rectal arteries
• Superior vein goes to portal via the inferior mesenteric. Middle and inferior veins go to internal iliac and internal pudendal portal - systemic anastomosis.
• Upper to inferior mesenteric nodes @L3, lower to internal iliac nodes
• From inferior hypogastric plexus

Question 13

Intestinal Table

Answer 13