Download Arteries - Princeton ISD

Blood Vessels

Blood is carried in a closed system of vessels that
begins and ends at the heart

The three major types of vessels are arteries,
capillaries, and veins

Arteries carry blood away from the heart, veins
carry blood toward the heart

Capillaries contact tissue cells and directly serve
cellular needs
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Generalized Structure of Blood Vessels



Arteries and veins are composed of three tunics –
tunica interna, tunica media, and tunica externa
Lumen – central blood-containing space
surrounded by tunics
Capillaries are composed of endothelium with
sparse basal lamina
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Generalized Structure of Blood Vessels
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.1b
Blood Vessel Anatomy
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Table 19.1
Elastic (Conducting) Arteries

Thick-walled arteries near the heart; the aorta and
its major branches

Large lumen allow low-resistance conduction of
blood

Contain elastin in all three tunics

Withstand and smooth out large blood pressure
fluctuations

Serve as pressure reservoirs
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Muscular (Distributing) Arteries and Arterioles


Muscular arteries – distal to elastic arteries; deliver
blood to body organs

Have thick tunica media with more smooth muscle

Active in vasoconstriction
Arterioles – smallest arteries; lead to capillary beds

Control flow into capillary beds via vasodilation
and constriction
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Capillaries


Capillaries are the smallest blood vessels

Walls consisting of a thin tunica interna, one cell
thick

Allow only a single RBC to pass at a time

Pericytes on the outer surface stabilize their walls
There are three structural types of capillaries:
continuous, fenestrated, and sinusoids
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Vascular Components
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.2a, b
Continuous Capillaries

Continuous capillaries are abundant in the skin and
muscles

Endothelial cells provide an uninterrupted lining

Adjacent cells are connected with tight junctions

Intercellular clefts allow the passage of fluids
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Continuous Capillaries

Continuous capillaries of the brain:

Have tight junctions completely around the
endothelium

Constitute the blood-brain barrier
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Continuous Capillaries
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.3a
Fenestrated Capillaries

Found wherever active capillary absorption or
filtrate formation occurs (e.g., small intestines,
endocrine glands, and kidneys)

Characterized by:

An endothelium riddled with pores (fenestrations)

Greater permeability than other capillaries
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Fenestrated Capillaries
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.3b
Sinusoids

Highly modified, leaky, fenestrated capillaries with
large lumens

Found in the liver, bone marrow, lymphoid tissue,
and in some endocrine organs

Allow large molecules (proteins and blood cells) to
pass between the blood and surrounding tissues

Blood flows sluggishly, allowing for modification
in various ways
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Sinusoids
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.3c
Capillary Beds

A microcirculation of interwoven networks of
capillaries, consisting of:


Vascular shunts – metarteriole–thoroughfare
channel connecting an arteriole directly with a
postcapillary venule
True capillaries – 10 to 100 per capillary bed,
capillaries branch off the metarteriole and return to
the thoroughfare channel at the distal end of the
bed
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Capillary Beds
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.4a
Capillary Beds
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.4b
Blood Flow Through Capillary Beds


Precapillary sphincter

Cuff of smooth muscle that surrounds each true
capillary

Regulates blood flow into the capillary
Blood flow is regulated by vasomotor nerves and
local chemical conditions
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Venous System: Venules

Venules are formed when capillary beds unite



Allow fluids and WBCs to pass from the
bloodstream to tissues
Postcapillary venules – smallest venules,
composed of endothelium and a few pericytes
Large venules have one or two layers of smooth
muscle (tunica media)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Venous System: Veins

Veins are:

Formed when venules converge

Composed of three tunics, with a thin tunica media
and a thick tunica externa consisting of collagen
fibers and elastic networks

Capacitance vessels (blood reservoirs) that contain
65% of the blood supply
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Venous System: Veins

Veins have much lower blood pressure and thinner
walls than arteries

To return blood to the heart, veins have special
adaptations


Large-diameter lumens, which offer little resistance
to flow

Valves (resembling semilunar heart valves), which
prevent backflow of blood
Venous sinuses – specialized, flattened veins with
extremely thin walls (e.g., coronary sinus of the
heart and dural sinuses of the brain)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Vascular Anastomoses

Merging blood vessels, more common in veins
than arteries

Arterial anastomoses provide alternate pathways
(collateral channels) for blood to reach a given
body region


If one branch is blocked, the collateral channel can
supply the area with adequate blood supply
Thoroughfare channels are examples of
arteriovenous anastomoses
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Blood Flow

Actual volume of blood flowing through a vessel,
an organ, or the entire circulation in a given
period:

Is measured in ml per min.

Is equivalent to cardiac output (CO), considering
the entire vascular system

Is relatively constant when at rest

Varies widely through individual organs
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Blood Pressure (BP)


Force per unit area exerted on the wall of a blood
vessel by its contained blood

Expressed in millimeters of mercury (mm Hg)

Measured in reference to systemic arterial BP in
large arteries near the heart
The differences in BP within the vascular system
provide the driving force that keeps blood moving
from higher to lower pressure areas
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Resistance


Resistance – opposition to flow

Measure of the amount of friction blood encounters

Generally encountered in the systemic circulation

Referred to as peripheral resistance (PR)
The three important sources of resistance are blood
viscosity, total blood vessel length, and blood
vessel diameter
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Factors Aiding Venous Return

Venous BP alone is too low to promote adequate
blood return and is aided by the:



Respiratory “pump” – pressure changes created
during breathing suck blood toward the heart by
squeezing local veins
Muscular “pump” – contraction of skeletal muscles
“milk” blood toward the heart
Valves prevent backflow during venous return
PLAY
InterActive Physiology ®: Anatomy Review:
Blood Vessel Structure and Function, pages 3–27
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Factors Aiding Venous Return
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.6
Maintaining Blood Pressure

Maintaining blood pressure requires:

Cooperation of the heart, blood vessels, and
kidneys

Supervision of the brain
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Maintaining Blood Pressure

The main factors influencing blood pressure are:

Cardiac output (CO)

Peripheral resistance (PR)

Blood volume

Blood pressure = CO x PR

Blood pressure varies directly with CO, PR, and
blood volume
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Temperature Regulation


As temperature rises (e.g., heat exposure, fever,
vigorous exercise):

Hypothalamic signals reduce vasomotor
stimulation of the skin vessels

Heat radiates from the skin
Sweat also causes vasodilation via bradykinin in
perspiration


Bradykinin stimulates the release of NO
As temperature decreases, blood is shunted to
deeper, more vital organs
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Circulatory Pathways

The vascular system has two distinct circulations


Pulmonary circulation – short loop that runs from
the heart to the lungs and back to the heart
Systemic circulation – routes blood through a long
loop to all parts of the body and returns to the heart
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Differences Between Arteries and Veins
Arteries
Veins
Delivery
Blood pumped into single
systemic artery – the aorta
Blood returns via superior and
interior venae cavae and the
coronary sinus
Location
Deep, and protected by
tissue
Both deep and superficial
Pathways
Fair, clear, and defined
Convergent interconnections
Supply/drainage
Predictable supply
Dural sinuses and hepatic portal
circulation
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Pulmonary Circulation
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.18b
Systemic Circulation
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.19
Internal carotid artery
External carotid artery
Vertebral artery
Brachiocephalic trunk
Axillary artery
Ascending aorta
Brachial artery
Abdominal aorta
Superior mesenteric artery
Gonadal artery
Inferior mesenteric
artery
Common iliac artery
External iliac artery
Digital arteries
Femoral artery
Common carotid arteries
Subclavian artery
Aortic arch
Coronary artery
Thoracic aorta
Branches of celiac trunk:
• Left gastric artery
• Splenic artery
• Common hepatic artery
Renal artery
Radial artery
Ulnar artery
Internal iliac artery
Deep palmar arch
Superficial palmar arch
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Arcuate artery
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.20b
Superficial
temporal artery
Basilar artery
Occipital artery
Vertebral artery
Internal
carotid artery
External
carotid artery
Common
carotid artery
Thyrocervical
trunk
Costocervical
trunk
Subclavian
artery
Axillary
artery
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Ophthalmic artery
Maxillary artery
Facial artery
Lingual artery
Superior thyroid
artery
Larynx
Thyroid gland
(overlying trachea)
Clavicle (cut)
Brachiocephalic
trunk
Internal thoracic
artery
Figure 19.21b
Arteries of the Brain
Anterior
Frontal lobe
Optic chiasma
Middle
cerebral
artery
Internal
carotid
artery
Pituitary
gland
Cerebral arterial
circle
(circle of Willis)
• Anterior
communicating
artery
• Anterior
cerebral artery
• Posterior
communicating
artery
• Posterior
cerebral artery
Basilar artery
Temporal
lobe
Pons
Occipital
lobe
Vertebral artery
Cerebellum
(c)
(d)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Posterior
Figure 19.21c,d
Common carotid
arteries
Right subclavian
artery
Left subclavian
artery
Left axillary
artery
Brachiocephalic
trunk
Vertebral artery
Thyrocervical trunk
Costocervical trunk
Suprascapular artery
Thoracoacromial artery
Axillary artery
Subscapular artery
Posterior circumflex
humeral artery
Anterior circumflex
humeral artery
Brachial artery
Posterior
intercostal
arteries
Anterior
intercostal
artery
Internal
thoracic
artery
Descending
aorta
Lateral
thoracic
artery
Deep artery
of arm
Common
interosseous
artery
Radial
artery
Ulnar
artery
Deep palmar arch
Superficial palmar arch
Digitals
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.22b
Arteries of the Abdomen
Liver (cut)
Inferior vena cava
Celiac trunk
Hepatic artery
proper
Common hepatic
artery
Right gastric artery
Gallbladder
Gastroduodenal
artery
Right gastroepiploic
artery
Duodenum
Abdominal aorta
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Diaphragm
Esophagus
Left gastric
artery
Left gastroepiploic
artery
Splenic artery
Spleen
Stomach
Pancreas
(major portion
lies posterior
to stomach)
Superior
mesenteric
artery
Figure 19.23b
Arteries of the Abdomen
Opening
for inferior
vena cava
Hiatus (opening)
for esophagus
Celiac trunk
Diaphragm
Inferior phrenic
artery
Middle suprarenal
artery
Renal artery
Kidney
Superior
mesenteric artery
Lumbar arteries
Abdominal aorta
Median sacral
artery
Gonadal (testicular
or ovarian) artery
Inferior
mesenteric artery
Common iliac artery
Ureter
(c)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.23c
Arteries of the Abdomen
Celiac trunk
Middle colic artery
Right colic artery
Ileocolic artery
Ascending colon
Ileum
Superior rectal
artery
Cecum
Appendix
Transverse colon
Superior
mesenteric artery
Intestinal arteries
Left colic artery
Inferior
mesenteric artery
Aorta
Sigmoidal arteries
Descending colon
Left common
iliac artery
Sigmoid colon
Rectum
(d)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.23d
Arteries of the
Lower Limbs
Common iliac artery
Internal iliac artery
Superior gluteal artery
External iliac artery
Deep artery of thigh
Lateral circumflex
femoral artery
Medial circumflex
femoral artery
Obturator artery
Femoral artery
Adductor hiatus
Popliteal artery
Anterior tibial artery
Posterior tibial artery
Fibular artery
Popliteal
artery
Posterior
tibial
artery
Lateral
plantar
artery
Medial
plantar
artery
Anterior
tibial
artery
Fibular
artery
Dorsalis
pedis artery
(from top
of foot)
Plantar
arch
(c)
Dorsalis pedis artery
Arcuate artery
Metatarsal arteries
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.24b, c
Dural sinuses
External jugular vein
Vertebral vein
Internal jugular vein
Superior vena cava
Axillary vein
Great cardiac vein
Hepatic veins
Hepatic portal vein
Superior mesenteric
vein
Inferior vena cava
Ulnar vein
Radial vein
Digital veins
Common iliac vein
External iliac vein
Femoral vein
Great saphenous vein
Popliteal vein
Posterior tibial vein
Anterior tibial vein
Fibular vein
Dorsal venous arch
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Subclavian vein
Right and left
brachiocephalic veins
Cephalic vein
Brachial vein
Basilic vein
Splenic vein
Median cubital vein
Renal vein
Inferior mesenteric vein
Internal iliac vein
Dorsal digital
veins
Figure 19.25b
Veins of the Head and Neck
Ophthalmic vein
Superficial
temporal vein
Facial vein
Occipital vein
(b)
Posterior
auricular vein
External
jugular vein
Vertebral vein
Internal
jugular vein
Superior and middle
thyroid veins
Brachiocephalic
vein
Subclavian
vein
Superior
vena cava
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.26b
Veins of the Brain
Superior sagittal
sinus
Falx cerebri
Inferior sagittal
sinus
Straight sinus
Cavernous sinus
Junction of sinuses
Transverse sinuses
Sigmoid sinus
Jugular foramen
(c)
Right internal
jugular vein
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.26c
Veins of the Upper Limbs and Thorax
Internal jugular vein
External jugular vein
Brachiocephalic veins
Left subclavian vein
Right subclavian vein
Superior vena cava
Axillary vein
Azygos vein
Accessory hemiazygos vein
Brachial vein
Cephalic vein
Basilic vein
Hemiazygos vein
Posterior
intercostals
Inferior
vena cava
Ascending
lumbar vein
Median
cubital vein
Median
antebrachial
vein
Cephalic
vein
Radial
vein
Basilic vein
Ulnar vein
Deep palmar
venous arch
Superficial palmar
venous arch
Digital veins
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.27b
Veins of the Abdomen
Hepatic veins
Inferior
phrenic vein
Inferior vena cava
Right
suprarenal vein
Left
suprarenal vein
Renal veins
Right
gonadal vein
External iliac vein
Left ascending
lumbar vein
Lumbar veins
Left
gonadal vein
Common iliac vein
Internal iliac vein
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.28b
Veins of the Abdomen
Hepatic veins
Liver
Hepatic portal vein
Gastric veins
Spleen
Inferior vena cava
Splenic vein
Right
gastroepiploic vein
Inferior
mesenteric vein
Superior
mesenteric vein
Small intestine
Large intestine
Rectum
(c)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 19.28c
Common iliac vein
Internal iliac vein
External iliac vein
Inguinal ligament
Femoral vein
Great saphenous
vein (superficial)
Great saphenous vein
Popliteal vein
Anterior tibial vein
Fibular (peroneal) vein
Popliteal vein
Fibular (peroneal)
vein
Anterior tibial vein
Small saphenous vein
(superficial)
Dorsalis pedis vein
Dorsal venous arch
Metatarsal veins
Plantar veins
(b)
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Posterior tibial vein
Plantar arch
Digital veins
(c)
Figure 19.29b, c