593
CHAPTER FIFTEEN
Cardiovascular System
Arteries to the Brain, Head, and Neck
Branches of the subclavian and common carotid arter-
ies supply blood to structures in the brain, head, and neck
(f
gs. 15.44
and
15.45)
. The main divisions of the subclavian
artery to these regions are the vertebral, thyrocervical, and
costocervical arteries. The common carotid artery communi-
cates with these regions by means of the internal and exter-
nal carotid arteries.
The
vertebral arteries
arise from the subclavian arteries
in the base of the neck near the tips of the lungs. They pass
upward through the foramina of the transverse processes of
the cervical vertebrae and enter the skull by way of the fora-
men magnum. Along their paths, these vessels supply blood
to vertebrae and to their associated ligaments and muscles.
In the cranial cavity, the vertebral arteries unite to form
a single
basilar artery.
This vessel passes along the ventral
brainstem and gives rise to branches leading to the pons,
midbrain, and cerebellum. The basilar artery terminates by
dividing into two
posterior cerebral arteries
that supply por-
tions of the occipital and temporal lobes of the cerebrum.
The posterior cerebral arteries also help form the
cerebral
arterial circle
(
circle of Willis
) at the base of the brain, which
connects the vertebral artery and internal carotid artery sys-
tems
(f
g. 15.46)
. The union of these systems provides alter-
nate pathways for blood to circumvent blockages and reach
brain tissues. It also equalizes blood pressure in the brain’s
5.
Renal
(re
nal)
arteries.
The renal arteries pass laterally
from the aorta into the kidneys. Each artery then divides
into several lobar branches in the kidney tissues.
6.
Gonadal
(go
nad-al)
arteries.
In a female, paired
ovarian arteries arise from the aorta and pass into the
pelvis to supply the ovaries. In a male,
spermatic arteries
originate in similar locations. They course downward
and pass through the body wall by way of the
inguinal
canal
to supply the testes.
7.
Inferior mesenteric artery.
Branches of this single
artery lead to the descending colon, the sigmoid colon,
and the rectum.
8.
Lumbar arteries.
Three or four pairs of lumbar arteries
arise from the posterior surface of the aorta in the region
of the lumbar vertebrae. These arteries supply muscles
of the skin and the posterior abdominal wall.
9.
Middle sacral artery.
This small, single vessel descends
medially from the aorta along the anterior surfaces
of the lower lumbar vertebrae. It carries blood to the
sacrum and coccyx.
The abdominal aorta terminates near the brim of the
pelvis, where it divides into right and left
common iliac
arteries.
These vessels supply blood to lower regions of the
abdominal wall, the pelvic organs, and the lower extremi-
ties
(f
g. 15.43)
.
Table 15.4
summarizes the major branches
of the aorta.
Right common carotid a.
Right internal jugular v.
Right subclavian a.
Brachiocephalic a.
Brachiocephalic vv.
Superior vena cava
Right pulmonary a.
Right pulmonary vv.
Right auricle
Pulmonary trunk
Left common carotid a.
Left internal jugular v.
Left subclavian a.
Aortic arch
Ligamentum arteriosum
Left pulmonary a.
Left pulmonary vv.
Left auricle
FIGURE 15.42
The major blood vessels associated with the heart. (
a.
stands for artery,
v.
stands for vein,
vv.
stands for veins.)
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