Blood Vessels And Nerves Of The Abdominal Cavity

Front 1

structures associated with the posterior abdominal wall include

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Back 1

a) vertebral column - projects into abdominal cavity, forming a gutter on either side
b) muscles of posterior wall - quadratus lumborum, psoas major
c) thoracic diaphragm - dome shaped; extends downward to overlap supeior ends of posterior abdominal wall muscles (psoas major & quadratus lumborum)
d) kidneys & suprarenal (adrenal) glands - located in gutters lateral to vertebral column, overlying posterior wall muscles
e) abdominal aorta, inferior vena cava and branches of each
f) sympathetic trunk with associated chain ganglia
g) lumbar plexus of nerves

Front 2

Abdominal Aorta

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Back 2

1) starts at entry into abdominal cavity through aortic hiatus of diaphragm and ends by bifurcating at level L4 vertebrae into right and left common iliac arteries
a) runs down midline of abdominal cavity; overlies vertebral bodies
2) unpaired branches of abdominal aorta:
a) celiac trunk - branches
1) left gastric artery - to lesser curvature of stomach
2) splenic artery - to pancreas and spleen
3) common hepatic artery - branches:
a) gastroduodenal artery - to stomach and duodenum
b) proper hepatic artery - to liver as part of portal triad; divides into right and left hepatic arteries (to right and left lobes of liver)

Front 3

Abdominal Aorta

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Back 3

b) superior mesenteric artery - through mesentery proper
1) supplies small intestine, cecum, ascending colon and 1/2 of transverse colon
c) inferior mesenteric artery
1) supplies second 1/2 of transverse colon, descending colon, sigmoid colon, rectum
3) paired branches of abdominal aorta
a) renal arteries - to kidneys
b) gonadal (testicular or ovarian) arteries - one pair per vertebral level; supply muscles of posterior & lateral abdominal wall
d) common iliac arteries - divide into external iliac artery and internal iliac artery

Front 4

Inferior Vena Cava

Back 4

1) begins at level of L5 vertebrae - formed by junction of common iliac veins
2) runs along right side of abdominal aorta
3) receives hepatic veins, renal veins, lumbar veins (from posterior body wall), right gonadal vein
4) passes through thoracic diaphragm via caval hiatus

Front 5

Portal venous drainage

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Back 5

1) liver functions in the metabolic processing & storage of nutrients after their absorption from the digestive tract
a) venous blood from stomach, small intestine & colon goes directlyto liver
b) liver cells store nutrients & remove toxins
c) blood exits liver via hepatic veins (usually 3) - drain into inferior vena cava
2) Hepatic portal venous system
a) arterial blood goes to capillaries of digestive tract - absorbs nutrients
b) leaves digestive tract in veins & goes to liver via hepatic portal vein
c) blood filters through capillaries between liver cells - exits liver via hepatic vein
d) hepatic vein empties into inferior vena cava - returns blood to heart

Front 6

Portal venous drainage

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Back 6

3) hepatic portal vein
a) formed by union of superior mesenteric vein & splenic vein
1) superior mesenteric vein receives blood from small intestine, ascending colon, & first part of transverse colon
2) splenic vein - receives drainage from stomach and spleen
b) inferior mesenteric vein drains second part of trancsverse colon, descending colon, sigmoid colon, & rectum; empties into splenic vein
c) left gastric vein from stomach - drains into hepatic portal vein
d) hepatic portal vein enters liver as part of portal triad (with common bile duct & proper hepatic artery)

Front 7

Blood flow through the liver

Back 7

1) the liver recieves 2 sources of blood:
a) arterial blood - from proper bepatic artery
b) portal venous blood - from hepatic portal vein
2) arterial & portal venous blood mix within capillaries of liver
3) blood exits liver via hepatic veins - drain into inferior vena cava for return to heart

Front 8

lumbar plexus

Back 8

formed by ventral rami of spinal cord nerves L1-L4; major branches:
1) femoral nerve - to muscles of anterior thigh; descends lateral to psoas major muscle
2) obturator nerve - to muscles of medial thigh; descends medial to psoas major muscle

Front 9

Autonomic Nervous System

Sympathic Trunk & Collateral ganglia and plexuses

Back 9

1) located alon either side of vertebral column
a) chain ganglia - location of postganglionic sympathetic neurons
b) white rami communicantes - from T1-L2 spinal nerves to sympathetic trunk (carry preganglionic sympathetic axons)
c) gray rami communicantes - from sympathetic trunk to all spinal nerves (carry postganglionic sympathetic axons)
2) collateral ganglia & plexuses
a) several sympathetic collateral ganglia located along abdominal aorta, at the base of the major arterial branches from the aorta
1) ganglia named for associated artery - celiac, superior mesenteric, and inferior mesenteric ganglia
b) ganglia receive splanchnic nerves - preganglionic sympathetic fibers from thoracic sympathetic trunk
1) splanchnic nerves exit sympathetic trunk in thorax - descend along lateral side of vertebral column and pass through diaphragm to enter abdomen
2) in abdomen, preganglionic sympathetic fibers pass to anterior side of aorta where they synapse onto postganglionic sympathetic neurons in collateral ganglia
a) collateral ganglia located at base of major arteries branching off of aorta
3) postganglionic sympathetic fibers distribute to target organs by following artery & its branches

Front 10

Autonomic Nervous System

vagal nerve fibers

Back 10

c) vagal nerve fibers - preganglionic parasympathetic fibers from vagus (X) nerve
1) vagus nerve descend through neck & thorax - pass through diaphragm with the esophagus to enter abdomen
2) in abdomen, vagal preganglionic parasympathetic fibers pass to anterior side of aorta where they mix with pre-and postganglionic sympathetic fibers
a) preganglionic parasympathetic do not synapse in collateral ganglia
b) mixture of sympathetic & parasympathetic fibers called a plexus (each plexus is named for associated artery - celiac, supeior & inferior mesenteric plexuses)
3) preganglionic parasympathetic fibers distribute with artery and its branches synapse in terminal ganglia located within walls of target organs
d) preganglionic parasympathetic fibers also exit from sacral (S2-S4) spinal cord - distribute to pelvic organs and synapse in terminal ganglia embedded in wall of target organ (bladder, uterus, prostate gland)
1) stimulate contraction of bladder during urination
*note: adrenal medulla also receives direct splanchnic (preganglionic sympathetic) nerve innervation
a) adrenal medulla secretes epinephrine when activated by sympathetic nervous system