Chapter 19
The Cardiovascular System: Blood Vessels
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19
their companion arteries. Superficial veins run just beneath
the skin and are readily seen, especially in the limbs, face,
and neck. Because there are no superficial arteries, the names
of the superficial veins do not correspond to the names of
any of the arteries.
Venous pathways are more interconnected.
Unlike the fairly
distinct arterial pathways, venous pathways tend to have nu-
merous interconnections, and many veins are represented by
not one but two similarly named vessels. As a result, venous
pathways are more difficult to follow.
The brain and digestive systems have unique venous drain-
age systems.
Most body regions have a similar pattern for
their arterial supply and venous drainage. However, the
venous drainage pattern in at least two important body ar-
eas is unique. First, venous blood draining from the brain
enters large
dural venous sinuses
rather than typical veins.
Second, blood draining from the digestive organs enters a
special subcirculation, the
hepatic portal system
, and perfuses
through the liver before it reenters the general systemic cir-
culation (see Table 19.12).
Principal Vessels of the
Systemic Circulation
Name and give the location of the major arteries and veins
in the systemic circulation.
Describe the structure and special function of the hepatic
portal system.
Except for special vessels and shunts of the fetal circulation (de-
scribed in Chapter 28), the principal arteries and veins of the sys-
temic circulation are described in
Tables 19.4
through
19.13
.
Notice that by convention, oxygen-rich blood is shown red,
while blood that is relatively oxygen-poor is depicted blue,
regardless of vessel type. ±e schematic flowcharts (pipe dia-
grams) that accompany each table show the vessels that would
be closer to the viewer in brighter, more intense colors than ves-
sels deeper or farther from the viewer. For example, darker blue
veins would be closer to the viewer than lighter blue veins in the
body region shown.
PART 3
Circulatory Pathways:
Blood Vessels of the Body
The Two Main Circulations
of the Body
Trace the pathway of blood through the pulmonary circuit,
and state the importance of this special circulation.
Describe the general functions of the systemic circuit.
±e term
vascular system
is o²en used to describe the body’s
complex network of blood vessels. However, the heart is actu-
ally a double pump that serves two distinct circulations, each
with its own set of arteries, capillaries, and veins. ±e
pulmo-
nary circulation
is the short loop that runs from the heart to
the lungs and back to the heart. ±e
systemic circulation
routes
blood through a long loop to all parts of the body before re-
turning it to the heart.
Table 19.3
on pp. 722–723 shows both
circuits schematically.
Systemic Arteries and Veins:
Differences in Pathways
and Courses
As we saw in Chapter 18, the heart pumps all of its blood into a
single systemic artery—the aorta. In contrast, blood returning
to the heart is delivered largely by two terminal systemic veins,
the superior and inferior venae cavae. ±e single exception to
this is the blood draining from the myocardium of the heart,
which is collected by the cardiac veins and reenters the right
atrium via the coronary sinus.
In addition to these differences between arteries and veins
connecting to the heart, there are three important differences
between systemic arteries and veins:
Arteries run deep while veins are both deep and superficial.
Deep veins parallel the course of the systemic arteries and
both are protected by body tissues along most of their course.
With a few exceptions, these veins are named identically to
(Text continues on p. 745.)
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