Lecture 6-Arteries And Nerves To Abdominal Organs I Flashcards
The aortic hiatus is formed by?
The right and left crus of the diaphragm
At what vertebral body does the abdominal aorta terminate?
-Bifurcates into?
- L4
- Bifurcates into right and left common iliac arteries
Where is the IVC relative to the aorta?
The IVC is to the right of the aorta
Where is the left renal vein relative to the aorta?
The left renal vein crosses anterior to the aorta
Where is the anterior longitudinal ligament relative to the aorta?
The anterior longitudinal ligament is POSTERIOR to the aorta
Where are the thoracic duct and the cisterna chyli relative to the aorta?
The thoracic duct and the cisterna chyli are to the right of the aorta
The thoracic duct drains which subclavian vein?
The thoracic duct drains the LEFT subclavian vein
Arteries that supply GI structures vs those that supply non-GI structures?
- Arteries that supply GI structures, branch anteriorly and are unpaired
- Arteries that supply non-GI structures branch laterally and are paired
Abdominal Aortic Aneurysm (AAA)
- What is it?
- Where is it usually located?
- Primarily due to?
- Presentation?
- Balloon-like dilation of the abdominal aorta
- Usually arises below the renal arteries and above the aortic bifurcation
- Primarily due to atherosclerosis
- Presents as pulsatile abdominal mass that grows with time
Palpation of aorta
Aorta should be no larger than 3 cm
Major complication of Abdominal Aortic Aneurysm?
Rupture (especially when greater than 5 cm)
Embryonic Gut regions
-Foregut-nerve plexus?
Celiac
Foregut-sympathetic innervation level?
T5-T9 greater splanchnic n
The abdominal aorta enters the abdomen through the?
Aortic hiatus
Structures located within the foregut?
Stomach, 1st and 2nd part of duodenum, liver, gall bladder, pancreas, spleen (mesoderm)
Midgut-sympathetic innervation level?
T10-T11 lesser splanchnic n
Midgut-nerve plexus?
SM
Structures located within midgut?
3rd and 4th part of duodenum, to proximal 2/3 of transverse colon
Hindgut-nerve plexus?
IM
Hindgut-sympathetic innervation level?
T12-L2 least splanchnic n
Structures located within the hindgut?
Distal 1/3 of transverse colon to upper portion of rectum
Celiac trunk
-Where does it branch off the aorta?
- T12-L1 immediately inferior to aortic hiatus
- Very short before branching
- Base of artery surrounded by celiac plexus and ganglion
Celiac trunk
-3 branches?
- Left gastric a
- Splenic a
- Common hepatic a
Celiac trunk branches
- Left gastric gives off?
- Anastomoses with?
- Gives off esophageal branches
- Will follow lesser curvature of stomach
- Anastomoses with right gastric artery along lesser curvature
Celiac trunk branches
- Splenic artery-Characteristics?
- Contained within what ligament?
- Runs posterior to stomach, superior to pancreas
- VERY TORTUOUS
- WITHIN SPLENORENAL LIGAMENT
Celiac trunk branches
-Splenic artery-branches?
- Short gastric arteries
- Left gastro-omental a
- Pancreatic branches-dorsal and inferior pancreatic arteries
Celiac trunk branches
- Splenic artery-Short gastric arteries
- Where are they located?
- Contained within what ligament?
- Upper part of the greater curvature
- Within gastrosplenic ligament
- Poor anastomoses
Celiac trunk branches
- Splenic artery-Left gastro-omental a
- Where is it located?
- Anastomoses with?
- Greater curvature of stomach
- Anastomoses with right gastro-ometal a
Common hepatic artery branches into 2 main arteries
-Which is superior and which is inferior?
- Proper hepatic artery (superior)
- Gastro-duodenal artery (inferior)
Proper hepatic artery gives off?
-Terminates as?
- Gives off right gastric artery
- Terminates as right and left hepatic arteries
Cystic artery is usually a branch off what artery?
Right hepatic artery
Gastroduodenal a
-Where is it located relative to the duodenum?
- Runs posterior to the duodenum
- May give off supraduodenal a
Gastroduodenal a
-Bifurcates into?
Bifurcates into right gastro-omental a and superior pancreaticoduodenal
Cholecystectomy
-Dissection is through?
Dissection is through hepatoduodenal ligament to reach the cystic artery which must be ligated before removing the gall bladder
Cholecystectomy
- Calot’s triangle
- Medially?
Common hepatic duct
Cholecystectomy
- Calot’s triangle
- Laterally?
Cystic duct
Cholecystectomy
- Calot’s triangle
- Superiorly?
Edge of liver
Cholecystectomy
- Calot’s triangle
- What artery crosses the middle of the triangle?
Cystic artery
Cholecystectomy
- Calot’s triangle
- Calot’s node?
Main route of lymphatic drainage of gallbladder
Superior Mesenteric artery
-Where does it emerge from aorta?
Posterior to the neck of the pancreas
Blood supply to the pancreas
-Pancreas receives branches from?
The pancreas receives branches from both the celiac and superior mesenteric arteries
Pancreatic blood supply
- The pancreas receives branches from both the celiac and superior mesenteric arteries
- Celiac?
- Branch of gastroduodenal
- Anterior and posterior superior pancreaticoduodenal arteries
Pancreatic blood supply
- The pancreas receives branches from both the celiac and superior mesenteric arteries
- Superior mesenteric a
Anterior and posterior inferior pancreaticoduodenal
Pancreatic blood supply
-Where is the anastomosis?
The branches from the superior mesenteric artery meet the branches from the gastroduodenal, forming anastomosing arcades on the anterior and posterior surfaces on the head of the pancreas
Pancreatic blood supply
- Anastomosis-If abdominal aorta is blocked between?
- What happens?
If the abdominal aorta is blocked between celiac trunk and SMA the superior and inferior pancreaticoduodenal aas compensate
Superior mesenteric artery
-Supplies branches to?
Supplies branches to the “free” small intestine and part of the large intestine (midgut derivatives)
Superior mesenteric artery
-Emerges from the aorta where? Then where does it go?
SMA emerges from the aorta posterior to the neck of the pancreas, to the left of the SMV, enters THE mesentery and runs between its layers to reach the ileum and jejunum
Superior mesenteric artery
-Branches to the small intestine?
- Inferior pancreaticoduodenal a
- Jejunal aa
- Ileal aa
SMA
-Jejunal aa characteristics?
Long vasa recta, simple arcades
SMA
-Ileal aa characteristics?
Short vasa recta, complex arcades
SMA branches to the large intestine?
- Ileocolic a
- Right colic
- Middle colic
SMA branches to the large intestine
-Ileocolic a-branches?
- Ileal branches
- Colic branch
- Anterior and posterior cecal branches
- Appendicular branch
SMA branches to large intestine
-Right colic a-branches?
- Branches to ascending colon
- Branches to right colic flexure
SMA branches to large intestine
-Middle colic a-branches?
- Right colic flexure
- Transverse colon
SMA branches to large intestine
-Marginal artery?
A continuous anastomoses
IMA branches?
- Left colic a (ascending and descending branches)
- Sigmoid aa
- superior rectal a
- marginal a
Ischemic colitis-risk factors?
Advanced age, clotting abnormalities, hypercholesterolemia, severe hypertension, adhesions, marathons
Ischemic colitis-Etiology?
Atherosclerosis, severe hypotension, blood clot/venous thrombosis, lupus or sickle cell, cocaine
Ischemic colitis
Tissue death perforation or bowel destruction
Rectal arteries and veins
-Superior rectal arteries and veins drain to?
Inferior mesenteric vein
Middle rectal arteries and veins drain to?
Internal iliac veins
Inferior rectal arteries and veins drain to?
Internal pudendal veins
Rectal arteries and veins
-Where do they anastomose?
Anastomose within the walls of the rectum and anus
Lymphatics of the GI system
-intestinal lymphatic trunk and cisterna chyli
Picture slide 38
Nerve plexi
- Several nerve plexi and ganglia located on the anterior and lateral surfaces of the aorta
- prevertebral sympathetic ganglia
- Named for nearest branch of the aorta or their location on the aorta
Nerve plexi
-Each plexus is a mix of?
Each plexus is a mix of sympathetic (fibers and cells), parasympathetic fibers and afferent fibers
Where are the sympathetic trunks located relative to the aorta?
The sympathetic trunks are lateral to the aorta
Nerve plexi (sympathetics)
- Sympathetic innervation?
- Where do the preganglionic fibers arise?
- Travel in?
- where do they synapse?
- Preganglionic fibers arise at T5-L1
- Travel in respective splanchnic nerves
- Synapse in prevertebral sympathetic ganglia
Nerve plexi (sympathetics) -Postganglionic fibers travel from?
Postganglionic fibers travel from ganglia to abdominal organs
Nerve plexi (parasympathetics)
- Parasympathetic innervation
- Preganglionic fibers travel through?
- Where do they synapse?
- Preganglionic fibers travel through celiac plexus but DO NOT SYNAPSE
- Synapse in nerve plexi of enteric (intrinsic) nervous system contained in gut wall
Nerve plexi (parasympathetics) -Parasympathetic innervation-supplied bby
Vagus and pelvic nerves
Nerve plexi (parasympathetics)
- Parasympathetic innervation
- Vagus innervates what portion(s) of the gut?
Foregut and midgut
Nerve plexi (parasympathetics)
- Parasympathetic innervation
- Pelvic nerves arise? Innervate?
Arise S2-S4
Innervate hindgut
Enteric Nervous System
- Composed of a series of?
- 2 components?
- Composed of a series of ganglionic nerve plexi contained within the gut wall
- Two components-Myenteric (Auerbach’s) and submucosal (Meissner’s)
Enteric Nervous System
- Myenteric plexus
- Between which layers?
- Function?
- Between outer longitudinal and inner circular muscle layers
- Motility
Enteric nervous system
- Submucosal plexus
- Function?
Secretions, blood flow, absorption
Hirschprung disease
-Pathology?
- Failure of neural crest cells to migrate during intestinal developement
- No myenteric plexus
- Neural crest cells become the enteric ganglion cells
- No parasympathetics so the gut cannot relax, causing constriction and megacolon of the proximal colon segments
Hirschsprung disease
-Where do most cases occur in the gut?
Rectosigmoid junction
Chagas disease
- Megacolon
- T. cruzi destroys autonomic nervous system MAINLY myenteric plexus
Nerves of the superior mesenteric plexus
-Sympathetics?
- Sympathetic fibers from the greater, lesser, and least splanchnic nerves synapse in the superior mesenteric ganglia
- Postganglionic fibers follow branches of the SMA to target organs
- GVA pain fibers follow sympathetics
Nerves of the superior mesenteric plexus
-Parasympathetics?
- Parasympathetics are from the vagus nerve
- They follow branches of the SMA to synapse in the walls of the target organ
- Accompanied by GVA fibers for visceral reflexes
Nerves of the inferior mesenteric plexus
-Part of the large intestine proximal to the splenic flexure is derived from?
- The part of the large intestine proximal to the splenic flexure is derived from midgut
- It is supplied by PS from the vagus nerve (+ GVA reflex fibers)
Nerves of the inferior mesenteric plexus
-Part of the large intestine distal to the splenic flexure is derived from?
The part of the large intestine distal to the splenic flexure is derived from hindgut and its PS are from sacral levels 2-4
At what vertebra does the abdominal aorta begin?
T12
Nerves of the inferior mesenteric plexus
-Sympathetic nerves follow?
Sympathetic nerves follow the superior or inferior mensenteric arteries from aortic plexi or from sacral splanchnic nerves (+ GVA pain fibers)
