Chapter 23
*Lecture Outline
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Chapter 23 Outline
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Anatomy of Blood Vessels
Blood Pressure
Systemic Circulation
Pulmonary Circulation
Review of Heart, Systemic, and
Pulmonary Circulation
• Aging and the Cardiovascular System
• Blood Vessel Development
Anatomy of Blood Vessels
• The three classes of blood vessels are
arteries, capillaries, and veins.
• Arteries carry blood away from the heart
and become progressively smaller as they
branch and finally result in capillaries.
• Veins return blood to the heart and
become progressively larger as they
merge and are closer to the heart.
Blood Vessel Tunics
Both artery and vein walls have three layers,
called tunics. From outer to inner:
1. Tunica externa (adventitia)—connective
tissue that helps anchor the blood vessel
to an organ; larger blood vessels require
their own blood supply; smaller arteries
that supply the larger arteries are called
vasa vasorum, which run through the
tunica externa
Blood Vessel Tunics—continued
2. Tunic media—comprised of circularly
arranged smooth muscle; sympathetic input
causes this smooth muscle to contract
resulting in vasoconstriction;
parasympathetic input results in vasodilation
3. Tunica intima (interna)—composed of an
endothelium (simple squamous epithelium
lining the inside of the arteries and veins) and
a subendothelial layer of areola connective
tissue
Blood Vessel Tunics
Figure 23.1
Comparison of Companion Vessels
Figure 23.3
Microscopic Comparison of
Arteries and Veins
Figure 23.2
Comparison of Arteries and Veins
Types of Arteries
Arteries are blood vessels that transport
blood away from the heart. There are three
types of arteries:
1. Elastic arteries
2. Muscular arteries
3. Arterioles
Types of Arteries
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Tunica intima
Tunica media
Elastic fibers throughout
tunica media
Tunica externa
LM 100x
(a) Elastic artery
Tunica intima
Internal elastic lamina
Tunica media
External elastic lamina
Tunica externa
LM 100x
(b) Muscular artery
Tunica media with few
layers of smooth muscle
Figure 23.4
LM 220x
(c)Arteriole
(all): © The McGraw-Hill Companies, Inc./Photo by Dr. Alvin Telser
Elastic Arteries
• Largest of the arteries (aorta, pulmonary,
brachiocephalic, common carotids, subclavians)
• Most examples are near the heart
• The elastic fibers present in all three tunics
allows these arteries to stretch under the
increased pressure generated by bloodflow from
the heart
• Elastic arteries branch into muscular arteries
Muscular Arteries
•
•
Medium diameter arteries
Possess elastic fibers in two concentric rings
between the three tunics:
1.
2.
•
the internal elastic lamina, which separates the
tunica intima and tunica media
the external elastic lamina, which separates the
tunica media and the tunica externa
Muscular arteries have a proportionately
thicker tunica media
Arterioles
• Smallest arteries
• Have less than six cell layers of smooth muscle
in their tunica media
• Sympathetic innervation to the muscle fiber cells
of the tunica media causes vasoconstriction
resulting in elevation of blood pressure
• Parasympathetic innervation causes
vasodilation and a lowering of blood pressure
Capillaries=Functional Units
• Smallest of all blood vessels
• Diameter only slightly larger than an
erythrocyte
• Wall consists solely of the tunica intima (a
single layer of endothelial cells)
• Only type of blood vessel where metabolic
exchange can occur between blood and
cells outside of the bloodstream
Capillaries
• Form capillary beds
• Each bed is fed by a metarteriole whose
proximal end is surrounded by smooth muscles
while the distal end, called the thoroughfare
channel, lacks smooth muscles
• The thoroughfare channel connects to a
postcapillary venule
• Branches from the metarteriole that begin with a
ring of smooth muscle on their walls are called
true capillaries
Capillary Bed Structure
Figure 23.5
Types of Capillaries
There are three types of capillaries:
1. Continuous—most common type; endothelial
cells form a continuous and complete lining (no
physical holes) aided by the presence of tight
junctions. Muscle, skin, thymus, CNS, lungs
2. Fenestrated—endothelial cells possess small
“holes” to allow fluid exchange between blood
and interstitial fluid. Kidneys, small intestine,
endocrine glands
3. Sinusoid—have big gaps between endothelial
cells that promotes transport of large
molecules and cells to and from the blood.
Bone marrow, anterior pituitary,
Parathyroid gland, spleen, liver
Types of Capillaries
Figure 23.6
Veins
• Veins are blood vessels that drain
capillaries and return blood to the heart.
• Pressure in veins is much lower than in
arteries.
• At rest, the body’s veins hold about 60% of
the body’s blood. Thus, veins function as
blood reservoirs.
Venules
• Smallest veins
• Companion vessels with arterioles
• Smallest ones are located at the distal end of a
capillary bed and are called postcapillary
venules
• Diapedesis (the migration of leukocytes from
the bloodstream to the body) occurs through the
walls of the postcapillary venules
• Venules merge to form veins
Veins
• Veins are larger than venules.
• Smaller and medium-sized veins travel with
muscular arteries.
• Large veins travel with elastic arteries.
• Blood pressure in veins is too low to overcome
the forces of gravity and possess valves.
• Valves are formed from the tunica intima and
prevent blood from pooling in the limbs.
• In addition, as skeletal muscles contract, they
also pump blood toward the heart. This process
is called the skeletal muscle pump.
Vein Valves and the Skeletal
Muscle Pump
Figure 23.7
Blood Pressure
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Systolic pressure
Blood pressure (mm Hg)
120
100
80
60
40
20
0
(a)
(b)
a: © Royalty-Free/Corbis
Figure 23.8
Diastolic
pressure
Fig13.25
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Blood volume
increases
Heart rate
increases
Stroke volume
increases
Blood pressure increases
Blood viscosity
increases
Peripheral resistance
increases
25
Systemic Circulation
• Consists of arteries and veins that travel to
and from all parts of the body except the
lungs.
Anterior View of Systemic Arteries
Figure 23.9
Anterior View of Systemic Veins
Figure 23.9
General Arterial Flow
Out of the Heart
•
Oxygenated blood is pumped out of left
ventricle into ascending aorta; ascending
aorta gives off two branches:
1.
2.
•
Left coronary artery
Right coronary artery
Aortic arch gives off three branches:
1.
2.
3.
Brachiocephalic trunk, which bifurcates into
right common carotid and right subclavian
arteries
Left common carotid artery
Left subclavian artery
General Arterial Flow
Out of the Heart
• Descending thoracic aorta follows the aortic
arch and gives off several branches to the
thoracic wall
• Renamed descending abdominal aorta when it
passes inferior and posterior to the diaphragm
• At the fourth lumbar vertebra, the aorta
bifurcates into left and right common iliac
veins
• Common iliac veins further divide into internal
and external iliac arteries
Insert Figure 23.9a
Figure 23.9
General Venous Return
to the Heart
• Inferior vena cava returns blood to the
right atrium from the lower limbs, pelvis
and perineum, and abdominal structures
• Superior vena cava is formed from a
fusion of the right and left
brachiocephalic veins and drains into the
right atrium
Insert Figure 23.9b
Figure 23.9
Blood Flow Through
the Head and Neck
• Left and right common carotid arteries
supply most of the blood to the head and
neck.
• At the superior border of the thyroid
cartilage, they divide into internal and
external carotid arteries.
Blood Flow Through Head and Neck
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Superficial temporal artery
Posterior auricular artery
Occipital artery
Maxillary artery
Facial artery
Ascending pharyngeal artery
Internal carotid artery
Lingual artery
External carotid artery
Carotid sinus
Common carotid artery
Superior thyroid artery
Vertebral artery
Thyrocervical trunk
Subclavian artery
Brachiocephalic trunk
Internal thoracic artery
(a) Arteries, right lateral view
Figure 23.10
Branches of
external carotid
artery
Branches of the External
Carotid Artery
1.
2.
3.
4.
5.
6.
Superior thyroid artery
Ascending pharyngeal artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular artery
*The external carotid artery then divides into the
maxillary artery and superficial temporal artery
Branches of the External
Carotid Artery
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Superficial temporal artery
Posterior auricular artery
Occipital artery
Maxillary artery
Facial artery
Ascending pharyngeal artery
Internal carotid artery
Lingual artery
External carotid artery
Carotid sinus
Common carotid artery
Superior thyroid artery
Vertebral artery
Thyrocervical trunk
Subclavian artery
Brachiocephalic trunk
Internal thoracic artery
(a) Arteries, right lateral view
Figure 23.10
Branches of
external carotid
artery
Blood Flow Through
the Head and Neck
• Venous blood return is through the
internal jugular vein or the external
jugular vein.
• These two veins drain into the subclavian
vein and then into the brachiocephalic
vein.
Blood Flow Through
the Head and Neck
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Superficial temporal vein
Posterior auricular vein
Maxillary vein
Pharyngeal vein
Facial vein
Lingual vein
Vertebral vein
External jugular vein
Internal jugular vein
Superior thyroid vein
Subclavian vein
Right brachiocephalic vein
Internal thoracic vein
(b) Veins, right lateral view
Figure 23.10
Blood Flow Through
the Cranium
• Internal carotid arteries enter the cranium
through the carotid canal.
• They divide into anterior and middle
cerebral arteries, which supply the brain,
and the ophthalmic arteries, which
supply the eyes.
Blood Flow Through
the Cranium
Figure 23.11
Blood Flow Through
the Cranium
• Vertebral arteries branch from the subclavian
arteries and travel through the transverse
foramina of the cervical vertebrae.
• They enter the cranium through the foramen
magnum where they merge to form the basilar
artery.
• The basilar artery and the internal carotid
arteries give off several branches that create an
anastomosis of arteries just superior to the sella
turcica called the cerebral arterial circle (circle
of Willis).
Blood Flow Through
the Cranium
• Most of the venous blood of the cranium
drains through the dural venous sinuses.
• These large veins are formed between the
two layers of dura mater.
• There are no valves in the dural venous
sinus system so blood can flow in more
than just one direction.
Major Components of the Dural
Venous Sinus System
1.
2.
3.
4.
5.
Superior sagittal sinus
Inferior sagittal sinus
Straight sinus
Left and right transverse sinuses
Left and right sigmoid sinuses
Major Components of the Dural
Venous Sinus System
Figure 23.11
Blood Flow Through the
Thoracic and Abdominal Walls
• The internal thoracic artery arises from the
subclavian artery.
• It gives rise to the upper anterior intercostal
arteries (1–6) and then continues on to become
the superior epigastric artery, which supplies
blood to the superior abdominal wall.
• The inferior epigastric artery is a branch of the
external iliac artery and supplies blood to the
inferior abdominal wall and forms an
anastomosis with the superior epigastric artery.
Blood Flow Through the
Thoracic and Abdominal Walls
Figure 23.12
Blood Flow Through the
Thoracic and Abdominal Walls
• All venous drainage from these areas drain on
the left side into the hemiazygos and
accessory hemiazygos veins.
• Venous drainage from the right side of these
areas drain into the azygos vein.
• The azygos vein receives blood from the
hemiazygos and accessory hemiazygos veins.
• Blood from the azygos vein drains into the
superior vena cava just before the superior vena
cava enters the right atrium.
Blood Flow Through the
Thoracic and Abdominal Walls
Figure 23.13
Blood Flow Through the
Thoracic Organs
•
•
•
The lungs are supplied by several bronchial arteries
that branch from the descending thoracic aorta.
The esophagus is mostly supplied by esophageal
arteries that branch from the descending aorta.
The diaphragm is supplied from three sources:
1.
2.
3.
Superior phrenic arteries—branches from the descending
thoracic aorta
Musculophrenic arteries—branches from the internal
thoracic arteries
Inferior phrenic arteries—branches from the descending
abdominal aorta
Blood Flow Through the Thoracic
and Abdominal Walls
Figure 23.12
Blood Flow Through the
Gastrointestinal Tract
•
•
Three unpaired arteries emerge from the
anterior wall of the descending
abdominal aorta.
These three arteries are responsible for
supplying the organs of the
gastrointestinal tract. They are:
–
–
–
celiac trunk
superior mesenteric artery
inferior mesenteric artery
Celiac Trunk
Located just inferior to the aortic opening of the
diaphragm, the celiac trunk gives off three
branches:
1. Left gastric artery—supplies lesser curvature
of stomach and lower esophagus
2. Splenic artery—supplies the spleen and part
of the stomach
3. Common hepatic artery—supplies the liver,
gall bladder, and a portion of the stomach
Celiac Trunk
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Diaphragm
Esophageal branches of
left gastric artery
Liver (cut)
Celiac trunk
Esophagus
Left gastric artery
Common hepatic artery
Hepatic artery proper
Left hepatic artery
Right hepatic artery
Gastroduodenal artery
Gallbladder
Right gastric artery
Duodenum
Right gastroepiploic artery
Splenic artery
Short gastric arteries
Pancreatic arteries
Spleen
Left gastroepiploic artery
Pancreas
Superior mesenteric artery
Descending abdominal aorta
Inferior vena cava
(a) Celiac trunk branches
Figure 23.15
Superior Mesenteric Artery
Located just inferior to the celiac trunk, the superior
mesenteric artery gives off the following branches:
1. Inferior pancreaticoduodenal arteries—supplies
portions of the pancreas and duodenum
2. Intestinal arteries—(18–20) that supply the jejunum
and ileum
3. Ileocolic artery—supplies the ileum, cecum, and
appendix
4. Right colic artery—supplies the ascending colon
5. Middle colic artery—supplies most of the transverse
colon
Superior Mesenteric Artery
Figure 23.15
Inferior Mesenteric Artery
Located just above the bifurcation of the
descending abdominal aorta at vertebral level L3,
the inferior mesenteric artery gives off the
following branches:
1. Left colic artery—supplies distal part of
transverse colon and proximal part of
descending colon
2. Sigmoid arteries—supplies the distal
descending colon and the sigmoid colon
3. Superior rectal artery—supplies the rectum
and upper half of the anal canal
Inferior Mesenteric Artery
Figure 23.15
Venous Return
from the Abdomen
• The hepatic portal system is a network
of veins that drains blood from the
gastrointestinal organs and shunts the
blood to the liver.
• The hepatic portal vein delivers nutrientrich blood to the liver is formed by a fusion
of three abdominal veins.
Hepatic Portal System
Figure 23.16
Hepatic Portal Vein
The three veins that merge to form the hepatic portal vein
are:
1. Inferior mesenteric vein—draining the distal
part of the colon
2. Splenic vein—draining the spleen, pancreas,
and stomach
3. Superior mesenteric vein—draining blood
from the small intestines, proximal part of colon,
pancreas, and stomach
Hepatic veins collect blood from liver and return it to the
inferior vena cava.
Hepatic Portal System
Figure 23.16
Blood Flow Through the
Posterior Abdominal Organs
Three paired arteries from the descending
abdominal aorta are:
1. Middle suprarenal arteries—supply the
adrenal gland
2. Renal arteries—supply the kidneys
3. Gonadal arteries—termed either the
testicular or ovarian arteries supplying
the gonads
Blood Flow Through the Posterior
Abdominal Organs
Figure 23.15
Blood Flow Through the Pelvis
and Perineum
The primary arterial supply to the pelvis and perineum is
the internal iliac artery; some of the branches from this
artery are:
1. Superior and inferior gluteal arteries—supply the
gluteal region
2. Obturator artery—supplies the medial thigh
3. Internal pudendal artery—supplies the anal canal and
the perineum
4. Middle rectal artery—supplies the lower portion of the
rectum
5. Uterine and vaginal arteries—supply the uterus and
vagina
Arterial Supply to the Pelvis
Insert Figure 23.18
Figure 23.18
Arterial Flow Through
the Upper Limb
• The right and left subclavian arteries supply
blood to the upper limbs.
• As the subclavian artery passes over the lateral
border of the first rib, its name changes to the
axillary artery.
• The axillary artery supplies the shoulder and
thoracic region.
• As the axillary artery passes the inferior border
of the teres major muscle, its name changes to
the brachial artery.
Arterial Flow Through
the Upper Limb
• In the cubital fossa, the brachial artery
bifurcates into the ulnar and radial
arteries.
• These arteries of the forearm anastomose
and form the superficial and deep
palmar arches in the palm of the hand.
• Digital arteries emerge from the arches to
supply the fingers.
Arterial
Flow to
the
Upper
Limb
Figure 23.19
Superficial Venous Drainage
of the Upper Limb
• On the dorsum of the hand, a dorsal
venous network drains into the basilic
and cephalic veins.
• In the cubital fossa, these two veins are
connected by the median cubital vein,
which is a common vein used for
venipuncture.
Venous Drainage from the Upper Limb
Figure 23.19
Deep Venous Drainage
of the Upper Limb
• The digital veins and superficial and deep
palmer venous arches drain into pairs of radial
and ulnar veins in the forearm.
• At the cubital fossa, the radial and ulnar veins
merge to form a pair of brachial veins.
• The brachial veins merge with the basilic vein to
form the axillary vein.
• The axillary vein changes its name to the
subclavian vein as it crosses superior to the
lateral border of the first rib.
Arterial Flow Through
the Lower Limb
• The right and left external iliac arteries
supply blood to the lower limb.
• As the external iliac passes inferior to the
inguinal ligament, its name changes to the
femoral artery, which gives off a branch
called the deep femoral artery.
• The deep femoral artery supplies the hip
joint via medial and lateral circumflex
arteries.
Arterial Flow to the Lower Limb
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Anterior view
Posterior view
Common iliac artery
External iliac artery
Internal iliac artery
Inguinal ligament
Obturator artery
Femoral circumflex arteries
Femoral circumflex
arteries
Femoral artery
Deep femoral artery
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Fibular artery
Fibular artery
Dorsalis pedis artery
Lateral plantar artery
Digital arteries
Medial plantar artery
Plantar arch
Figure 23.20
(a) Arteries of right lower limb
Arterial Flow Through
the Lower Limb
• The femoral artery enters the posterior
popliteal fossa, where its name is changed
to the popliteal artery.
• The popliteal artery supplies the knee joint
and muscles in that region.
• The popliteal artery divides into the
anterior and posterior tibial arteries,
which supply the anterior and posterior
compartments of the leg, respectively.
Arterial Flow Through
the Lower Limb
• The posterior tibial artery gives off a branch
called the fibular artery, which supplies the
lateral compartment of the leg.
• The posterior tibial artery divides into the medial
and lateral plantar arteries in the foot.
• The anterior tibial artery changes its name to the
dorsalis pedis artery at the anterior surface of
the ankle. It and a branch of the lateral plantar
artery unite to form the plantar arch.
• Digital arteries extend from the arch to supply
the toes.
Superficial Venous Drainage
of the Lower Limb
• On the dorsum of the foot, a dorsal
venous arch drains into the great
saphenous vein medially and the small
saphenous vein laterally.
• The great saphenous vein drains into the
femoral vein and the small saphenous vein
drains into the popliteal vein.
Venous Drainage
of the Lower Limb
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Anterior view
Posterior view
Common iliac vein
External iliac vein
Internal iliac vein
Femoral circumflex veins
Femoral circumflex veins
Deep femoral vein
Femoral vein
Great saphenous vein
Popliteal vein
Small saphenous vein
Anterior tibial veins
Fibular veins
Fibular veins
Posterior tibial veins
Great saphenous vein
Medial plantar veins
Dorsal venous arch
Lateral plantar veins
Figure 23.20
Deep veins
Superficial veins
Digital veins
(b) Veins of right lower limb
Deep Venous Drainage
of the Lower Limb
• Digital veins and deep veins of the foot drain into
pairs of medial and lateral plantar veins.
• These veins drain into a pair of posterior tibial
veins.
• On the dorsum of the foot and ankle, deep veins
drain into a pair of anterior tibial veins.
• The anterior and posterior tibial veins merge to
form the popliteal vein in the popliteal fossa.
Deep Venous Drainage
of the Lower Limb
• The popliteal vein curves onto the anterior thigh
compartment and becomes the femoral vein.
• Once the femoral vein passes superior to the
inguinal ligament, it changes its name to the
external iliac vein.
• When the external iliac vein fuses with the
internal iliac vein, the new vein becomes the
common iliac vein.
• The left and right common iliac veins merge to
form the inferior vena cava.
Pulmonary Circulation
• Responsible for carrying deoxygenated
blood from the right side of the heart to the
lungs and returning newly oxygenated to
the left side of the heart
• In this circulation, arteries carry
deoxygenated blood and veins carry
oxygenated blood
• This is opposite the systemic circulation
Pulmonary Circulation
• Deoxygenated blood exits the right
ventricle into the pulmonary trunk, which
bifurcates into right and left pulmonary
arteries that go to the lungs.
• These arteries branch into arterioles and
then capillaries and finally return to the left
atrium as pulmonary veins.
Pulmonary Circulation
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Aortic arch
Pulmonary
trunk
Left pulmonary artery
Right pulmonary artery
Right pulmonary veins
Left pulmonary veins
Left atrium
Right atrium
Left ventricle
Right ventricle
(a)
Branch of
pulmonary artery
Branch of
pulmonary vein
Pulmonary
capillaries
Arteriole
Venule
Alveoli
Figure 23.22
(b)
Circulatory Routes
Figure 23.23
Thoracic Artery Development
Figure 23.24
Development of Vitelline
and Umbilical Veins
Figure 23.25
Cardinal Vein Development
Figure 23.26
Fetal and Newborn Circulation
Figure 23.27