6: Abdominal Midgut And Hindgut Flashcards
Are jejunum and ileum retro or intraperitoneal?
Intraperitoneal
How much of the SI is jejunum vs ileum
Jejunum: proximal 2/5ths
Ileum: distal 3/5ths
Blood supply to jejunum and ileum
Jejunum: long vasa recta off SMA
Ileum: short vasa recta off SMA
Colon length
1.5 meters
What are the fatty appendages on haustra called?
Appendices epiploicae
Where are ileal papilla?
Cecum
Ileocecal valve
Regulates passage into cecum
What does the appendix contain
Several lymphoid nodules
Where is the appendix?
Attached to posteromedial cecum, supported by mesoappendix
What two parts of the colon are secondarily retroperitoneal
Ascending and descending colon
At what level does the sigmoid colon join rectum?
S3
What suspends the transverse and sigmoid colons?
Transverse: transverse mesocolon mesentery
Sigmoid: sigmoid mesocolon
Rectum is both retroperitoneal and what?
Sub-peritoneal
Three transverse rectal folds
Superior, middle, and inferior folds in rectum
Pectinate line location
At inferior ends of anal valves
Of the many anastomoses between SMA and IMA, name one
Marginal artery (of Drummond)
Three arteries to the rectum and what they branch from
- Superior rectal: IMA
- middle rectal: internal iliac A
- Inferior rectal: internal pudendal
Three plexuses where the portal venous system has anastomoses with the systemic system
Gastroesophageal plexus, umbilicus, rectal venous plexus
What is notable at the plexuses where portal and systemic blood can mix?
Varices can occur here due to decreased blood flow through liver
What artery’s branches do the sacral splanchnics run with on the way to the pelvic viscera
Internal iliac A
Four parts of the preaortic plexus
Celiac ganglia, SMA ganglia, IMA ganglia, aorticorenal ganglia
Somatic vs visceral afferent pathways
Somatic: pain from irritation of peritoneum
Visceral: pain from organ itself
How does the somatic afferent pathway work?
Brain interprets pain as though irritation occurred in skin of region supplied by same sensory ganglia and SC segments
How does the visceral afferent pathway work?
Pain is transmitted via splanchnic nerves to spinal cord, but is poorly localized so it radiates to same dermatome level receiving visceral afferents
