small intestine, pancreas, large intestine and mesenteric arteries Flashcards
1st part of the duodenum
- mucosa is smooth
- also referred to bulb, ampulla, cap
2nd-4th part of the duodenum
-mucosa and submucosa form numerous folds
circular folds
- mucosa and submucosa form these in the 2nd-4th parts of the duodenum
- spiral chyme onward for continuous break up and mixing
major duodenal papilla
- near head of pancreas
- contains opening to hepatopancreatic ampulla
- longitudinal fold right below this in the dudoenum
- has a hood over it.
minor duodenal papilla
- superior to major duodenal papilla
- contains opening of accessory pancreatic duct
What keeps the jejunum and Ileum attached to the abdominal wall?
the mesenteric root of the mesentery of the small intestine, posteriorly
Arcades of mesentery in Jejunum
1-2 loops
Arcades of mesentery in the Ileum
3+ loops
Arcades of mesentery
Where ileo/jejunal branches anastomes
Vasa Recta of mesentery
straight arteries that come off arcades
Vasa recta of jejunum
Long
Vasa recta of Ileum
short
circular folds of ileum
few and small
circular fold of jejunem
large and many
Histology of duodenum
Brunner’s glands of the submucosa
Brunner’s glands
in the submucoas of duodenum, secret mucus
Histology of Ileum
Peyer’s pathes of the Mucosa (lamina Propria) and submucosa
Peter’s Patches
In the lamina propria of the mucosa and submucosa in the ileum
lymphatic nodules
Histology of Jejunum
nothing special
Pancreatic cells
99% exocrine
Acini
clusters of exocrine cells in pancreas that produces digestive enzymes which flow into the GI tract though a network of ducts
What do cells that are associated with acinar cells priduce?
sodium bicarbonate which makes the fluid alkaline
pancreatic juices
the collective secretions from the exocrine cells
-will digest carbs, proteins, and fats
main pancreatic duct
-exits pancreas and merges with the common bile duct
common bile duct
from the liver and gallbladder
hepatopancreatic ampulla
the combined common bile duct and main pancreatic duct that enters the duodenum (visibile as the major duodenal papilla)
accessory pancreatic duct
-smaller, second duct exits the pancreas to empty into the duodenum
Where does the accessory pancreatic duct empty into in the duodenum?
minor dudodenal papilla
Path of Bile flow from the liver into the duodenum
R/L hepatic ducts—common hepatic duct (joined by cystic duct)—-common bile duct (joins main pancreatic duct)—-hepatopancreatic ampulla (delivery route of bile into the duodenum at the major duodenal papilla)
identifying external features of the large intestine
- Teniae Coli
- Omental appendices (epiploic appendices)
- Haustra
Teniae Coli
ligament-type things that are running along the length of the large intestine. they are shorter than the actual large intestine causing it to “scrunch” up and form haustra
omental appendices (epiploic appendices)
unique to large intestine
-NOT in rectum
Haustra
- Large intestine
- Pouches
internal features of Large intestine
- Ileal orifice
- superior and inferior lips
- orifice of the appendix
Ileal orifice
- internal feature of LI
- keeps the ileum from releasing too much into cecum all at once
- located on medial wall
superior and inferior lips of the ileal orifice
- LI
- form the ileocecal valve POSTMORTEM
Ileal papilla
- LI
- form the ileocecal valve IN VIVO
orifice of the appendix
- LI
- located inferior to the ileal orifice
Large intestine histology
- goblet cells abundant in the mucosa
- allows for easier movement of fecal matter in large intestine
Appendix
-contains large groupings of lymphatic nodules (similar to Peyer’s patches) that are located in the lamina propria and A LITTLE in the submucosa
Appendicitis onset
-mild pain near umbilicus
Why is there mild pain near umbilicus with onset of appendicitis?
sensory fibers of appendix goes to umbilical region at first
appendicitis a couple hours in
pain/tenderness to touch is located in RLQ over McBurney’s point
-normal to experience nausea and vomitting
McBurney’s point
Draw imaginary line from umbilicus to iliac crest and at about the lateral 3rd of that line is where the appendix USUALLY sits, it can vary greatly
superior mesenteric artery
- L1
- unpaired branch from abdominal aorta
what does the superior mesenteric artery supply?
- head of pancreas
- distal part of duodenum
- jejunum
- ileum
- cecum
- appendix
- ascending colon
- proximal 2/3 of transverse colon
Branches of the superior mesenteric artery
- inferior pancreaticoduodenal artery
- Middle Colic artery
- right colic artery
- ileocecal artery
- intestinal /jejunal and ileal arteries
inferior pancreaticoduodenal artery
- 1st branch from the superior mesenteric artery
- smallest
SUPPLIES
- lower part of head of pancreas
- distal half of duodenum
Middle colic artery
-branch from superior mesenteric artery
SUPPLIES
-proximal 2/3 of transverse colon
Right colic artery
-branch from superior mesenteric artery
SUPPLIES
- ascending colon
- beginning of transverse colon
Ileocolic artery
-branch from the superior mesenteric artery
SUPPLIES
- terminal ileum
- cecum
- appendix
- begging of ascending colon
Intestinal/Jejunal and Ileal arteries
- branch from the superior mesenteric artery
- form arterial arcades which give rise to straight arteries that supply intetinal wall (12-15 off to the left)
Inferior mesenteric
- unpaired branch of abdonimal aorta at L3
- supplies distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, and upper half of anal canal
branches of the inferior mesenteric artery
- left colic artery
- sigmoid arteries
- superior rectal artery
Left colic artery
-branch from inferior mesenteric artery
SUPPLIES
- distal 1/3 of transverse colon
- descending colon
Sigmoid arteries
-branch from the inferior mesenteric artery
SUPPLIES
-sigmoid colon
Superior rectal artery
-branch from the inferior mesenteric artery
SUPPLIES
- rectum
- upper half of anal canal
sympathetic innervation of abdominal part of GI tract and accessory organs
- preganglionic fibers origiante in lower thoracic and upper lumabr spinal cord segments
- leave spinal cord in corresponding spinal nerves
- white communicating rami
- pass THROUGH symp trunk (don’t synapse)
- leave in splanchnic nerves (greater,lesser,least)
- terminate in prevertebral ganglia (associated with abdominal aorta) where they synapse with postganglionic neurons
celiac ganglion
- prevertebral ganglion (infant of vertebral column)
- supplies postganglionic fibers to:
- somtach
- upper duodenum
- pancreas
- liver
- gallbladder
- spleen
superior mesenteric ganglion (structures supplied by mesenteric artery)
- prevertebral ganglion
- supplies postganaglionic symp fibers to:
- lower duodenum
- jejunum
- ileum
- cecum
- appendix
- ascending colon
- proximal 2/3 transverse colon
inferior mesenteric ganglion (structures supplied by inferior mesenteric artery)
- prevertebral ganglion
- supplies postganglionic symp fibers to:
- distal 1/3 transverse colon
- descending colon
- sigmoid colon
- rectum
- upper anal canal
*same as artery
symp innervation of ab/GI
- postganglionic fibers originate from prevertebral ganglia
- form plexuses around corresponding arteries and their branches to reach target organs (innervate same organs arteries supply)
Parasympathetic innervation of Ab/GI
- Vagus nerve and pelvic splanchnic carry pre/postganglionic fibers
- vagus enters abdomen as the anterior and posterior vagal trunks
- vagal branches join celiac plexus and superior mesenteric plexus
- target organs are reached via these plexuses
- synapse with postganglionic neurons in walls of target organs
- distributed along with branches of the abdominal aorta
what carries preganglionic parasymp fibers?
vagus nerves and pelvic splanchnic nerves
Where does the vagus nerve vary preganglionic parasympathetic fibers from?
spinal cord segments S2-S4
Where do the preganglionic parasymp fibers enter from the vagus nerve?
inferior hypogastric plexus and inferior mesenteric plexus
-target organs are reached via these plexuses
Where preganglionic parasymp fibers synapse once they go to the inferior hypogastric plexus and inferior mesenteric plexus?
synapse with postganglionic fibers in walls of target organs
-distributed along with branches of the inferior mesenteric artery
