Lab 18 Flashcards
Blood vessels are a closed system of passages that transport
blood around the body.
The heart pumps blood away
from the heart through a series of arteries.
Arteries branch as they pass through organs and tissues to form progressively smaller vessels until they branch into
tiny capillary beds,
tiny capillary beds,
where gas, nutrient, and waste exchange take place.
The blood is drained from the capillaries via a
series of veins that return the blood to the heart.
The three major circuits of blood flow in the body are the following:
systemic; coronary; pulmonary
- Systemic.
The systemic circuit consists of a series of arteries that deliver oxygenated blood to capillary beds within the body’s tissues, and a set of veins that return deoxygenated blood back to the heart.
- Coronary.
The coronary circuit is similar to the systemic circuit except its arteries, capillary beds, and veins supply and drain only the heart.
- Pulmonary.
The pulmonary circuit features a set of arteries that deliver deoxygenated blood to the capillary beds of the lungs, and a set of veins that return oxygenated blood to the heart.
The systemic arterial circuit begins with the
largest artery in the body, the aorta.
The aorta originates from the
left ventricle as the ascending aorta, which ascends until it curves around to form the aortic arch.
There are three major branches off the aortic arch:
the brachiocephalic trunk, the left common carotid artery, and the left subclavian artery.
The brachiocephalic trunk (bray-kee-oh-seh-FAL-ik)
is a small trunk that veers to the right. Shortly after passing deep to the clavicle, it splits into the right common carotid and right subclavian arteries.
The arterial supply of the head and neck comes primarily from the
right and left common carotid arteries (kuh-RAWT-id;
Notice that the right and left common carotid arteries have different origins—the right side branches from the
brachiocephalic trunk, and the left side from the aortic arch.
In the neck, these arteries branch into the
internal and external carotid arteries.
The external carotid artery gives off many branches that supply the
structures of the head, neck, and face.
One of its terminal branches is the
large superficial temporal artery, which crosses the temporal bone to supply the scalp.
The internal carotid arteries pass through the
carotid canals to enter the cranial cavity, where they give off branches called the anterior and middle cerebral arteries that supply the brain.
The two anterior cerebral arteries are connected by a
small anterior communicating artery.
Also supplying the brain are the
vertebral arteries, which branch from the subclavian arteries.
The vertebral arteries then pass through the
vertebral foramina of the cervical vertebrae and enter the cranial cavity through the foramen magnum.
At the brainstem, the two vertebral arteries fuse to become the
single basilar artery (BAY-zih-lur), splitting again near the pituitary gland into the posterior cerebral arteries. These vessels give off small posterior communicating arteries, connecting the circulation of the basilar artery with that of the internal carotid arteries.
These vessels form a continuous structure known as the
cerebral arterial circle.
The connection provides
alternate routes of circulation to the brain if one of the arteries supplying the brain becomes blocked.
The arterial supply to the upper limb begins with the
right and left subclavian arteries (sub-KLAY-vee-in; Fig. 18.6). The
The subclavian artery becomes the
axillary artery near the axilla.
In the arm, the axillary artery becomes the
brachial artery
brachial artery (BRAY-kee-uhl), which splits into the
radial artery and the ulnar artery just distal to the antecubital fossa.
As you would expect, these arteries travel alongside the bones for which they are named—
the radial artery is lateral and the ulnar artery is medial.
Near the left superior sternal border, the aortic arch curves inferiorly to become
the thoracic aorta.
The thoracic aorta descends through the thoracic cavity posterior to the heart, giving off
posterior intercostal arteries, after which it passes through the diaphragm to become the abdominal aorta.
The six major branches of the abdominal aorta, include the following:
celiac trunk; middle suprarenal arteries; renal arteries; superior mesenteric artery; gonadal arteries; inferior mesenteric artery
- Celiac trunk.
The short, stubby celiac trunk is the first branch of the abdominal aorta.
The celiac trunk spilts almost immediately into the
common hepatic artery
common hepatic artery supplies the
liver, stomach, pancreas, and duodenum (part of the small intestine);
the splenic artery (SPLEN-ik), which supplies the
spleen, stomach, and pancreas;
and the left gastric artery,
which supplies the stomach.
- Middle suprarenal arteries.
Just inferior to the celiac trunk are the small middle suprarenal arteries, which supply the adrenal glands that are located on top of the kidneys.
- Renal arteries.
Inferior to the celiac trunk we find the two renal arteries (REE-nuhl), which serve the kidneys. Note that the kidneys are posterior to the other abdominal organs in Figure 18.7 and so the renal arteries are slightly obscured by other organs and vessels. They are also seen more clearly in Figure 18.3.
- Superior mesenteric artery.
In the same vicinity of the renal arteries is another branch called the superior mesenteric artery (mez-en-TEHR-ik). As its name implies, it travels through the membranes of the intestines (called the mesentery) and supplies the small and much of the large intestine.
- Gonadal arteries.
Inferior to the superior mesenteric arteries we find a small pair of arteries that serve the reproductive organs, or gonads, and so are called the gonadal arteries.
- Inferior mesenteric artery.
The last large branch off the abdominal aorta is the inferior mesenteric artery, which supplies the remainder of the large intestine.
The abdominal aorta terminates by
bifurcating into two common iliac arteries (ILL-ee-ak), which themselves bifurcate into an internal iliac artery and an external iliac artery (Figs. 18.7 and 18.8).
The internal iliac artery supplies structures of the
pelvis, and the external iliac artery passes deep to the inguinal ligament to enter the anterior thigh, where it becomes the femoral artery.
In the proximal thigh, the femoral artery gives off
the deep femoral artery, which travels posteriorly to supply the hip joint, femur, and other structures in the thigh.
The femoral artery remains anterior until
about midway down the thigh when it also passes posteriorly to become the popliteal artery (pahp-lih-TEE-uhl;
popliteal artery (pahp-lih-TEE-uhl;
named for the popliteal fossa, or the posterior knee).
Just distal to the popliteal fossa, the popliteal artery divides
into its two main branches: the anterior tibial artery, which continues in the anterior foot as the dorsalis pedis artery (dohr-SAL-iss PEE-diss), and the posterior tibial artery,
dorsalis pedis artery (dohr-SAL-iss PEE-diss), and the posterior tibial artery,
which curls underneath the medial malleolus and continues to the plantar surface of the foot.
Arteries of the Trunk
aorta; brachiocephalic trunk; subclavian artery; celiac trunk middle suprarenal artery; superior mesenteric artery; gonadal arteries; inferior mesenteric artery; common iliac artery
- Aortaa.
Ascending aortab. Aortic archc. Thoracic aortad. Abdominal aorta
- Celiac trunka.
Common hepatic arteryb. Splenic arteryc. Left gastric artery
- Middle suprarenal arteries
- Renal arteries
- Common iliac artery
a. Internal iliac arteryb. External iliac artery
Arteries of the Head and Neck
- Common carotid arteries; 2. External carotid artery; 3. Internal carotid artery; 4. Vertebral artery; 5. Basilar artery; 6. Cerebral arterial circle