b.
Hepatic portal circulation
Inferior vena cava
Stomach
Hepatic vein
Liver
Hepatic portal vein
Superior mesenteric vein
^
Heart.
^
Inferior vena
cava
Abdominal
aorta
Hepatic
veins
Hepatic
artery
Splenic
vein
\
Superior
mesenteric
vein
Tributaries from portions
of stomach, pancreas, and
portions of large intestine
Tributaries from small intestine and
portions of large intestine,
stomach, and pancreas
Spleen
Splenic vein
Inferior mesenteric
vein
vein. This is an exception to the
general
principle
that
venous
blood
returns
directly
to
the
heart. However, because this ve-
nous blood is rich in substances
absorbed from the gastrointestinal tract, this setup al-
lows the liver to process the absorbed substances before
they pass into the general circulation. This allows nutri-
ent levels to be relatively stable throughout the body. The
liver also receives oxygenated blood from the hepatic ar-
tery. Within the liver, oxygenated blood mixes with portal
venous blood, and all venous blood exits via the hepatic
veins, where the blood enters the general circulation.
portal vein
A vein
that carries blood
from one capillary
network to another.
CONCEPT CHECK
1.
What
blood vessel structure is unique to
veins?
2.
What
forces drive the exchange of fluid across
the capillary wall?
3.
How
does the skeletal muscle pump work?
4.
How
is the pulmonary circulation different
from the systemic circulation?
Blood Vessels Are the Body's Plumbing 331
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