Download 21-7 The Systemic Circuit

An Introduction to Blood Vessels and
Circulation
• Blood Vessels
• Are classified by size and histological organization
• Are instrumental in overall cardiovascular
regulation
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21-1 Classes of Blood Vessels
• Arteries
• Carry blood away from heart
• Arterioles
• Are smallest branches of arteries
• Capillaries
• Are smallest blood vessels
• Location of exchange between blood and interstitial fluid
• Venules
• Collect blood from capillaries
• Veins
• Return blood to heart
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Figure 21-1 Comparisons of a Typical Artery and a Typical Vein (Part 1 of 2).
Tunica externa
Tunica media
Tunica intima
Smooth muscle
Lumen
of vein
Internal elastic
membrane
External
elastic
membrane
Endothelium
Lumen
of
artery
Elastic fiber
ARTERY
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Artery and vein
LM × 60
Figure 21-1 Comparisons of a Typical Artery and a Typical Vein (Part 2 of 2).
Tunica externa
Tunica media
Tunica intima
Lumen
of vein
Smooth
muscle
Lumen
of
artery
Artery and vein
© 2015 Pearson Education, Inc.
Endothelium
LM × 60
VEIN
21-1 Blood Vessels
• Differences between Arteries and Veins
• Arteries and veins run side by side
• Arteries have thicker walls and higher blood
pressure
• Collapsed artery has small, round lumen (internal
space)
• Vein has a large, flat lumen
• Vein lining contracts, artery lining does not
• Artery lining folds
• Arteries more elastic
• Veins have valves
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21-1 Structure and Function of Arteries
• Arteries
• Elasticity allows arteries to absorb pressure waves
that come with each heartbeat
• Contractility
• Arteries change diameter
• Controlled by sympathetic division of ANS
• Vasoconstriction
• The contraction of arterial smooth muscle by the
ANS
• Vasodilation
• The relaxation of arterial smooth muscle
• Enlarging the lumen
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21-1 Structure and Function of Arteries
• Vasoconstriction and Vasodilation
• Affect:
1. Afterload on heart
2. Peripheral blood pressure
3. Capillary blood flow
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21-1 Structure and Function of Arteries
• Arteries
• From heart to capillaries, arteries change
• From elastic arteries
• To muscular arteries
• To arterioles
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21-1 Structure and Function of Arteries
• Elastic Arteries
• Also called conducting arteries
• Large vessels (e.g., pulmonary trunk and aorta)
• Tunica media has many elastic fibers and few
muscle cells
• Elasticity evens out pulse force
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21-1 Structure and Function of Arteries
• Muscular Arteries
• Also called distribution arteries
• Are medium sized (most arteries)
• Tunica media has many muscle cells
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21-1 Structure and Function of Arteries
• Arterioles
• Are small
• Have little or no tunica externa
• Have thin or incomplete tunica media
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21-1 Structure and Function of Arteries
• Artery Diameter
• Small muscular arteries and arterioles
• Change with sympathetic or endocrine stimulation
• Constricted arteries oppose blood flow
• Resistance (R)
• Resistance vessels – arterioles
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21-1 Structure and Function of Arteries
• Aneurysm
• A bulge in an arterial wall
• Is caused by weak spot in elastic fibers
• Pressure may rupture vessel
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Figure 21-2 Histological Structure of Blood Vessels.
Veins
Arteries
Large Vein
Elastic Artery
Internal elastic
membrane
Tunica externa
Tunica media
Endothelium
Endothelium
Tunica
intima
Tunica media
Tunica intima
Tunica externa
Medium-sized Vein
Muscular Artery
Tunica externa
Tunica externa
Tunica media
Tunica media
Endothelium
Endothelium
Tunica
intima
Tunica intima
Venule
Arteriole
Smooth muscle cells (tunica media)
Tunica externa
Endothelium
Endothelium
Basement membrane
Capillaries
Fenestrated Capillary
Pores
Endothelial cells
Basement membrane
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Continuous Capillary
Endothelial
cells
Basement membrane
21-1 Structure and Function of Capillaries
• Capillary Structure
•
•
•
•
Endothelial tube, inside thin basement membrane
No tunica media
No tunica externa
Diameter is similar to red blood cell
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Figure 21-3 Capillary Structure.
Basement
membrane
Endothelial cell
Nucleus
Endosomes
Fenestrations,
or pores
Endosomes
Basement
membrane
Boundary
between
endothelial
cells
a Continuous capillary
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Boundary
between
endothelial
cells
Basement
membrane
b Fenestrated capillary
Gap between
adjacent cells
c Sinusoid
Figure 21-4a The Organization of a Capillary Bed.
Vein
Smooth
muscle cells
Collateral
arteries
Venule
Arteriole
Metarterioles
Thoroughfare
channel
Capillaries
Section of
precapillary
sphincter
Small
venule
Precapillary
sphincters
Arteriovenous
anastomosis
a A typical capillary bed. Solid arrows
indicate consistent blood flow;
dashed arrows indicate variable or
pulsating blood flow.
© 2015 Pearson Education, Inc.
KEY
Consistent
blood flow
Variable
blood flow
21-1 Structure and Function of Capillaries
• Thoroughfare Channels
• Direct capillary connections between arterioles
and venules
• Controlled by smooth muscle segments
(metarterioles)
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21-1 Structure and Function of Capillaries
• Collaterals
• Multiple arteries that contribute to one capillary
bed
• Allow circulation if one artery is blocked
• Arterial anastomosis
• Fusion of two collateral arteries
• Arteriovenous anastomoses
• Direct connections between arterioles and venules
• Bypass the capillary bed
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21-1 Structure and Function of Capillaries
• Angiogenesis
• Formation of new blood vessels
• Vascular endothelial growth factor (VEGF)
• Occurs in the embryo as tissues and organs
develop
• Occurs in response to factors released by cells
that are hypoxic, or oxygen-starved
• Most important in cardiac muscle, where it takes
place in response to a chronically constricted or
occluded vessel
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21-1 Structure and Function of Capillaries
• Vasomotion
• Contraction and relaxation cycle of capillary
sphincters
• Causes blood flow in capillary beds to constantly
change routes
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21-1 Structure and Function of Veins
• Veins
• Collect blood from capillaries in tissues and
organs
• Return blood to heart
• Are larger in diameter than arteries
• Have thinner walls than arteries
• Have lower blood pressure
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21-1 Structure and Function of Veins
• Venules
• Very small veins
• Collect blood from capillaries
• Medium-Sized Veins
• Thin tunica media and few smooth muscle cells
• Tunica externa with longitudinal bundles of elastic
fibers
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21-1 Structure and Function of Veins
• Large Veins
• Have all three tunica layers
• Thick tunica externa
• Thin tunica media
• Venous Valves
• Folds of tunica intima
• Prevent blood from flowing backward
• Compression pushes blood toward heart
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Figure 21-5 The Function of Valves in the Venous System.
Valve
closed
Valve opens superior
to contracting muscle
Valve
closed
Valve closes inferior
to contracting muscle
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Figure 21-6 The Distribution of Blood in the Cardiovascular System.
Large veins
18%
Large venous
networks (liver,
bone marrow, skin)
21%
Venules and
medium-sized veins
25%
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21-1 Blood Vessels
• Capacitance of a Blood Vessel
• The ability to stretch
• Relationship between blood volume and blood
pressure
• Veins (capacitance vessels) stretch more than
arteries
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21-1 Blood Vessels
• Venous Response to Blood Loss
• Vasomotor center stimulates sympathetic nerves
• Systemic veins constrict (venoconstriction)
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21-2 Pressure and Resistance
• Total Capillary Blood Flow
• Equals cardiac output
• Is determined by:
• Pressure (P) and resistance (R) in the
cardiovascular system
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21-2 Pressure and Resistance
• Pressure (P)
• The heart generates P to overcome resistance
• The Pressure Gradient (∆P)
• Circulatory pressure
• The difference between:
• Pressure at the heart
• And pressure at peripheral capillary beds
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21-2 Pressure and Resistance
• Flow (F)
• Is proportional to the pressure difference (∆P)
• Divided by R
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21-2 Pressure and Resistance
• Measuring Pressure
• Blood pressure (BP)
• Arterial pressure (mm Hg)
• Capillary hydrostatic pressure (CHP)
• Pressure within the capillary beds
• Venous pressure
• Pressure in the venous system
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21-2 Pressure and Resistance
• Circulatory Pressure
• ∆P across the systemic circuit (about 100 mm Hg)
• Circulatory pressure must overcome total
peripheral resistance
• R of entire cardiovascular system
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21-2 Pressure and Resistance
• Total Peripheral Resistance
• Vascular resistance
• Blood viscosity
• Turbulence
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21-2 Pressure and Resistance
• Vascular Resistance
• Due to friction between blood and vessel walls
• Depends on vessel length and vessel diameter
• Adult vessel length is constant
• Vessel diameter varies by vasodilation and
vasoconstriction
• R increases exponentially as vessel diameter
decreases
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21-2 Pressure and Resistance
• Viscosity
• R caused by molecules and suspended materials
in a liquid
• Whole blood viscosity is about four times that of
water
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21-2 Pressure and Resistance
• Turbulence
• Swirling action that disturbs smooth flow of liquid
• Occurs in heart chambers and great vessels
• Atherosclerotic plaques cause abnormal
turbulence
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21-2 Pressure and Resistance
• Arterial Blood Pressure
• Systolic pressure
• Peak arterial pressure during ventricular systole
• Diastolic pressure
• Minimum arterial pressure during diastole
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21-2 Pressure and Resistance
• Abnormal Blood Pressure
• Normal = 120/80
• Hypertension
• Abnormally high blood pressure
• Greater than 140/90
• Hypotension
• Abnormally low blood pressure
© 2015 Pearson Education, Inc.
Case Study – Blood Pressure
William, a 5'6", 210 lb., 64-year-old male business executive had a
physical exam prior to his retirement from corporate work. His
blood pressure was >180/115 on three separate days. Further
examination showed normal to low plasma renin activity,
elevated peripheral resistance (PR), cardiac output (CO) of 7.2
L/min (normal approx 5L/min), x-ray evidence of left
ventricular hypertrophy, retinal hemorrhages, and mild
polyuria. Recommended therapy was weight reduction to his ideal
level, a low-salt diet (<2 gm/day sodium), prudent exercise, and a
reduction in alcohol consumption (<3 oz whiskey/day). This
change in lifestyle did little to change the condition. Medication
was initiated in the form of an oral diuretic and progressed to a
beta-blocker; eventually a vasodilator was included to reduce the
blood pressure to <140/90.
© 2015 Pearson Education, Inc.
© 2015 Pearson Education,
Mean Arterial Pressure can be defined as the average arterial pressure
during a single cardiac cycle.
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Pressure is generated as blood is pumped out of the
left ventricle into the aorta and distributing arteries.
Mean Aterial Pressure (MAP)
MAP = CO x PR (SVP-Systemic Vascular
Resistance)
Cardiac Output (CO)
* The amount of blood pumped by HEART per minute
(ml/min) ( 5 L/m rest; up to 21 L/min)
* CO=SV x HR (e.g 70 ml/beat x 71 BPM = 4,970 ml/min)
SV: Stroke volume of blood pumped w/ each heart beat
HR: Heart rate or number of times heart beats per minute
* CO changes w/ stress, anxiety, drugs, heart disease or 
body temp
Peripheral Resistance (PR)
* Opposition to flow through BLOOD VESSELS. It is an
Index of friction or drag
* Determined by:
blood vessels diameter (the most significant regulator of
blood flow)
blood viscosity (doesn’t change much from moment to
moment)
 viscosity with anemia, hypoproteinemia
 viscosity with polycythemia , dehydration
blood vessel length (doesn’t change much from moment to
moment)
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CVP – Central Venous Pressure
Which is usually 0
Cardiovascular Regulation
• Controlling Cardiac Output, Peripheral
Resistance and, therefore, Blood Pressure
– Autoregulation
• Causes immediate, localized homeostatic adjustments
– Neural mechanisms
• Respond quickly to changes at specific sites
– Endocrine mechanisms
• Direct long-term changes
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Autoregulation
Autoregulation involves
changes in the pattern of
blood flow within capillary
beds as precapillary
sphincters open and close
in response to chemical
changes in the interstitial
fluid. Factors that promote
the dilation of blood vessels
are called vasodilators.
Local vasodilators such as
lactic acid accelerate blood
flow through their tissue of
origin.
HOMEOSTASIS
RESTORED
Local decrease
in resistance
and increase in
blood flow
HOMEOSTASIS
Local vasodilators
released
Inadequate
local blood
pressure and
blood flow
HOMEOSTASIS DISTURBED
• Physical stress (trauma,
high temperature)
• Chemical changes
(decreased O2 or pH,
increased CO2)
• Increased tissue activity
© 2015 Pearson Education, Inc.
Normal
blood pressure
and volume
Start
Central Regulation
Central regulation involves both
neural and endocrine mechanisms.
Activation of the cardiovascular center
involves both the cardioacceleratory
center (which stimulates the heart)
and the vasomotor center (which
controls the degree of peripheral
vasoconstriction). Neural mechanisms
Neural
mechanisms
Stimulation of
receptors sensitive
to changes in
systemic blood
pressure or
chemistry
Activation of
cardiovascular
center
Short-term elevation
of blood pressure by
sympathetic
stimulation of the
heart and peripheral
vasoconstriction
elevate cardiac output and reduce
blood flow to nonessential or inactive
tissues. The primary vasoconstrictor
involved in neural regulation is
norepinephrine (NE). Endocrine
mechanisms involve long-term
increases in blood volume and blood
pressure.
Stimulation
of endocrine
response
Long-term increase
in blood volume
and blood pressure
Endocrine mechanisms
If autoregulation is ineffective
HOMEOSTASIS
RESTORED
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Cardiovascular Regulation
• Autoregulation of Blood Flow within Tissues
– Adjusted by peripheral resistance while cardiac
output stays the same
• Local vasodilators accelerate blood flow at tissue level
– Low O2 or high CO2 levels
– Low pH (acids)
– Nitric oxide (NO) released by endothelium cells of blood
vessels causes relaxation of smooth muscle
– High K+ or H+ concentrations
– Chemicals released by inflammation (histamine)
– Elevated local temperature
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Cardiovascular Regulation
• Autoregulation of Blood Flow within Tissues
– Adjusted by peripheral resistance while cardiac
output stays the same
• Local vasoconstrictors
– Examples: endothelins (peptides that constrict blood vessels
and raise blood pressure)
– Clotting factors released by damaged tissues
– Constrict precapillary sphincters
– Affect a single capillary bed
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Cardiovascular Regulation
• Neural Mechanisms
– Cardiovascular (CV) centers of the medulla
oblongata
• Cardiac centers
– Cardioacceleratory center increases cardiac output
– Cardioinhibitory center reduces cardiac output
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Cardiovascular Regulation
• Angiotensin II
– Responds to fall in renal blood pressure
– Stimulates:
•
•
•
•
Aldosterone production
ADH production
Thirst
Cardiac output and peripheral vasoconstriction
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Cardiovascular Regulation
• Erythropoietin (EPO)
– Released at kidneys
– Responds to low blood pressure, low O2 content in
blood
– Stimulates red blood cell production
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The Hormonal Regulation of Blood Pressure and Blood Volume.
HOMEOSTASIS
Normal blood
pressure and
volume
HOMEOSTASIS
DISTURBED
Start
HOMEOSTASIS
RESTORED
Blood pressure
and volume decrease
Decreasing blood
pressure and
volume
Blood pressure
and volume increase
Short-term
Long-term
Sympathetic activation
and release of adrenal
hormones E and NE
Endocrine Response
of Kidneys
Renin release leads
to angiotensin II
activation
Erythropoietin (EPO)
is released
Increased cardiac
output and
peripheral
vasoconstriction
Angiotensin II Effects
Antidiuretic hormone
released
Aldosterone secreted
Thirst stimulated
a Factors that compensate
for decreased blood
pressure and volume
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Increased red blood
cell formation
Combined Short-Term
and Long-Term Effects
Increased
blood
pressure
Increased
blood
volume
Cardiovascular Regulation
• Natriuretic Peptides
– Atrial natriuretic peptide (ANP)
• Produced by cells in right atrium
– Brain natriuretic peptide (BNP)
• Produced by ventricular muscle cells
– Respond to excessive diastolic stretching
– Lower blood volume and blood pressure
– Reduce stress on heart
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The Hormonal Regulation of Blood Pressure and Blood Volume.
Responses to ANP and BNP
Increased Na + loss in urine
Increased water loss in urine
Natriuretic
peptides released
by the heart
Decreased thirst
Combined Effects
Inhibition of ADH, aldosterone,
epinephrine, and
norepinephrine release
Decreased blood
volume
Peripheral vasodilation
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Increasing blood
pressure and
volume
Decreasing blood
pressure and
volume
HOMEOSTASIS
Increasing blood
pressure and
volume
b Factors that compensate for
increased blood pressure and
volume
© 2015 Pearson Education, Inc.
Normal
blood pressure
and volume
Case Study – Blood Pressure
William, a 5'6", 210 lb., 64-year-old male business executive had a physical exam prior
to his retirement from corporate work. His blood pressure was >180/115 on three
separate days. Further examination showed normal to low plasma renin activity, elevated
total peripheral resistance (TPR), cardiac output (CO) of 7.2 L/min (normal approx
5L/min), x-ray evidence of left ventricular hypertrophy, retinal hemorrhages, and mild
polyuria (hypertension causes excessive kidney filtration). Recommended therapy was
weight reduction to his ideal level, a low-salt diet (<2 gm/day sodium), prudent exercise,
and a reduction in alcohol consumption (<3 oz whiskey/day). This change in lifestyle did
little to change the condition. Medication was initiated in the form of an oral diuretic
(excess water excretion and lower blood volume) and progressed to a beta-blocker
(blocks receptors for epinephrine and norepinephrine which slows down your heart rate
and reduce the force of heart contraction, also blocks kidneys from producing a
angiotensin II, reducing the amount of angiotensin so blood vessels relax and widen,
making it easier for blood to flow through; eventually a vasodilator was included to
reduce the blood pressure to <140/90.
© 2015 Pearson Education, Inc.
© 2015 Pearson Education,
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Venous Pressure and Venous Return
• Determines the amount of blood arriving at right
atrium each minute
• Low effective pressure in venous system
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21-2 Pressure and Resistance
• Venous Pressure and Venous Return
• Low venous resistance is assisted by:
• Muscular compression of peripheral veins
• Compression of skeletal muscles pushes blood
toward heart (one-way valves)
• The respiratory pump
• Thoracic cavity action
• Inhaling decreases thoracic pressure
• Exhaling raises thoracic pressure
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21-2 Pressure and Resistance
• Capillary Pressures and Capillary Exchange
• Vital to homeostasis
• Moves materials across capillary walls by:
• Diffusion
• Filtration
• Reabsorption
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21-2 Pressure and Resistance
• Diffusion
• Movement of ions or molecules
• From high concentration
• To lower concentration
• Along the concentration gradient
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21-2 Pressure and Resistance
• Diffusion Routes
1. Water, ions, and small molecules such as
glucose
• Diffuse between adjacent endothelial cells
• Or through fenestrated capillaries
2. Some ions (Na+, K+, Ca2+, Cl−)
• Diffuse through channels in plasma membranes
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21-2 Pressure and Resistance
• Diffusion Routes
3. Large, water-soluble compounds
• Pass through fenestrated capillaries
4. Lipids and lipid-soluble materials such as O2 and
CO2
• Diffuse through endothelial plasma membranes
5. Plasma proteins
• Cross endothelial lining in sinusoids
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21-2 Pressure and Resistance
• Filtration
• Driven by hydrostatic pressure
• Water and small solutes forced through capillary
wall
• Leaves larger solutes in bloodstream
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21-2 Pressure and Resistance
• Reabsorption
• The result of osmotic pressure (OP)
• Blood colloid osmotic pressure (BCOP)
• Equals pressure required to prevent osmosis
• Caused by suspended blood proteins that are too
large to cross capillary walls
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Figure 21-10 Capillary Filtration.
Capillary
hydrostatic
pressure
(CHP)
Amino acid
Blood protein
Glucose
Ions
Interstitial
fluid
Small solutes
Hydrogen
bond
Water
molecule
Endothelial
cell 1
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Endothelial
cell 2
21-2 Pressure and Resistance
• Interplay between Filtration and Reabsorption
1. Ensures that plasma and interstitial fluid are in
constant communication and mutual exchange
2. Accelerates distribution of:
• Nutrients, hormones, and dissolved gases
throughout tissues
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Interplay between Filtration and Reabsorption
3. Assists in the transport of:
• Insoluble lipids and tissue proteins that cannot
enter bloodstream by crossing capillary walls
4. Has a flushing action that carries bacterial toxins
and other chemical stimuli to:
• Lymphatic tissues and organs responsible for
providing immunity to disease
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Interplay between Filtration and Reabsorption
• Net hydrostatic pressure
• Forces water out of solution
• Net osmotic pressure
• Forces water into solution
• Both control filtration and reabsorption through
capillaries
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Factors that Contribute to Net Hydrostatic
Pressure
1. Capillary hydrostatic pressure (CHP)
2. Interstitial fluid hydrostatic pressure (IHP)
• Net capillary hydrostatic pressure tends to push
water and solutes:
• Out of capillaries
• Into interstitial fluid
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Net Capillary Colloid Osmotic Pressure
• Is the difference between:
1. Blood colloid osmotic pressure (BCOP) and
2. Interstitial fluid colloid osmotic pressure (ICOP)
• Pulls water and solutes:
• Into a capillary
• From interstitial fluid
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Net Filtration Pressure (NFP)
• The difference between:
• Net hydrostatic pressure
• Net osmotic pressure
NFP = (CHP – IHP) – (BCOP – ICOP)
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Capillary Exchange
• At arterial end of capillary:
• Fluid moves out of capillary
• Into interstitial fluid
• At venous end of capillary:
• Fluid moves into capillary
• Out of interstitial fluid
© 2015 Pearson Education, Inc.
21-2 Pressure and Resistance
• Capillary Exchange
• Transition point between filtration and reabsorption
• Is closer to venous end than arterial end
• Capillaries filter more than they reabsorb
• Excess fluid enters lymphatic vessels
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Figure 21-11 Forces Acting across Capillary Walls.
Return to
circulation
3.6 L/day flows
into lymphatic
vessels
Arteriole
Venule
Filtration
24 L/day
35
25
mm mm
Hg
Hg
Reabsorption
No net fluid
movement
25
mm
Hg
25
mm
Hg
20.4 L/day
18
mm
Hg
25
mm
Hg
NFP = +10 mm Hg
NFP = 0
NFP = 7 mm Hg
CHP > BCOP
Fluid forced
out of capillary
CHP = BCOP
No net
movement
of fluid
BCOP > CHP
Fluid moves
into capillary
© 2015 Pearson Education, Inc.
KEY
CHP (Capillary
hydrostatic pressure)
BOP (Blood
osmotic pressure)
NFP (Net filtration
pressure)
21-2 Pressure and Resistance
• Capillary Dynamics
• Hemorrhaging
• Reduces CHP and NFP
• Increases reabsorption of interstitial fluid (recall of
fluids)
• Dehydration
• Increases BCOP
• Accelerates reabsorption
• Increase in CHP or BCOP declines
• Fluid moves out of blood
• Builds up in peripheral tissues (edema)
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Tissue Perfusion
•
•
•
•
Blood flow through the tissues
Carries O2 and nutrients to tissues and organs
Carries CO2 and wastes away
Is affected by:
• Cardiac output
• Peripheral resistance
• Blood pressure
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Cardiovascular Regulation Changes Blood Flow
to a Specific Area
1. At an appropriate time
2. In the right area
3. Without changing blood pressure and blood flow
to vital organs
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Controlling Cardiac Output and Blood Pressure
• Autoregulation
• Causes immediate, localized homeostatic
adjustments
• Neural mechanisms
• Respond quickly to changes at specific sites
• Endocrine mechanisms
• Direct long-term changes
© 2015 Pearson Education, Inc.
Figure 21-12 Short-Term and Long-Term Cardiovascular Responses (Part 2 of 2).
Autoregulation
Autoregulation involves
changes in the pattern of
blood flow within capillary
beds as precapillary
sphincters open and close
in response to chemical
changes in the interstitial
fluid. Factors that promote
the dilation of blood vessels
are called vasodilators.
Local vasodilators such as
lactic acid accelerate blood
flow through their tissue of
origin.
HOMEOSTASIS
RESTORED
Local decrease
in resistance
and increase in
blood flow
HOMEOSTASIS
Local vasodilators
released
Inadequate
local blood
pressure and
blood flow
HOMEOSTASIS DISTURBED
• Physical stress (trauma,
high temperature)
• Chemical changes
(decreased O2 or pH,
increased CO2 or
prostaglandins)
• Increased tissue activity
© 2015 Pearson Education, Inc.
Normal
blood pressure
and volume
Start
Figure 21-12 Short-Term and Long-Term Cardiovascular Responses (Part 1 of 2).
Central Regulation
Central regulation involves both
neural and endocrine mechanisms.
Activation of the cardiovascular center
involves both the cardioacceleratory
center (which stimulates the heart)
and the vasomotor center (which
controls the degree of peripheral
vasoconstriction). Neural mechanisms
Neural
mechanisms
Stimulation of
receptors sensitive
to changes in
systemic blood
pressure or
chemistry
Activation of
cardiovascular
center
Short-term elevation
of blood pressure by
sympathetic
stimulation of the
heart and peripheral
vasoconstriction
elevate cardiac output and reduce
blood flow to nonessential or inactive
tissues. The primary vasoconstrictor
involved in neural regulation is
norepinephrine (NE). Endocrine
mechanisms involve long-term
increases in blood volume and blood
pressure.
Stimulation
of endocrine
response
Long-term increase
in blood volume
and blood pressure
Endocrine mechanisms
If autoregulation is ineffective
HOMEOSTASIS
RESTORED
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Autoregulation of Blood Flow within Tissues
• Adjusted by peripheral resistance while cardiac
output stays the same
• Local vasodilators accelerate blood flow at tissue
level
•
•
•
•
•
•
© 2015 Pearson Education, Inc.
Low O2 or high CO2 levels
Low pH (acids)
Nitric oxide (NO)
High K+ or H+ concentrations
Chemicals released by inflammation (histamine)
Elevated local temperature
21-3 Cardiovascular Regulation
• Autoregulation of Blood Flow within Tissues
• Adjusted by peripheral resistance while cardiac
output stays the same
• Local vasoconstrictors
•
•
•
•
© 2015 Pearson Education, Inc.
Examples: prostaglandins and thromboxanes
Released by damaged tissues
Constrict precapillary sphincters
Affect a single capillary bed
21-3 Cardiovascular Regulation
• Neural Mechanisms
• Cardiovascular (CV) centers of the medulla
oblongata
• Cardiac centers
• Cardioacceleratory center increases cardiac output
• Cardioinhibitory center reduces cardiac output
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Vasomotor Center
• Control of vasoconstriction
• Controlled by adrenergic nerves (NE)
• Stimulates smooth muscle contraction in arteriole
walls
• Control of vasodilation
• Controlled by cholinergic nerves (NO)
• Relaxes smooth muscle
• Vasomotor Tone
• Produced by constant action of sympathetic
vasoconstrictor nerves
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Reflex Control of Cardiovascular Function
• Cardiovascular centers monitor arterial blood
• Baroreceptor reflexes
• Respond to changes in blood pressure
• Chemoreceptor reflexes
• Respond to changes in chemical composition,
particularly pH and dissolved gases
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Baroreceptor Reflexes
• Stretch receptors in walls of:
1. Carotid sinuses (maintain blood flow to brain)
2. Aortic sinuses (monitor start of systemic circuit)
3. Right atrium (monitors end of systemic circuit)
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Baroreceptor Reflexes
• When blood pressure rises, CV centers:
• Decrease cardiac output
• Cause peripheral vasodilation
• When blood pressure falls, CV centers:
• Increase cardiac output
• Cause peripheral vasoconstriction
© 2015 Pearson Education, Inc.
Figure 21-13 Baroreceptor Reflexes of the Carotid and Aortic Sinuses (Part 1 of 2).
Cardioinhibitory
center stimulated
Cardioacceleratory
center inhibited
Responses to Increased
Baroreceptor Stimulation
Decreased
cardiac
output
Vasomotor center
inhibited
Baroreceptors
stimulated
Vasodilation
occurs
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Increasing blood
pressure
Blood pressure
decreases
Start
HOMEOSTASIS
Normal range
of blood
pressure
© 2015 Pearson Education, Inc.
Figure 21-13 Baroreceptor Reflexes of the Carotid and Aortic Sinuses (Part 2 of 2).
HOMEOSTASIS
Start
Normal range
of blood
pressure
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Decreasing blood
pressure
Blood pressure
increases
Vasoconstriction
occurs
Baroreceptors
inhibited
Vasomotor center
stimulated
Responses to Decreased
Baroreceptor Stimulation
Cardioacceleratory
center stimulated
Cardioinhibitory
center inhibited
© 2015 Pearson Education, Inc.
Increased
cardiac
output
21-3 Cardiovascular Regulation
• Chemoreceptor Reflexes
• Peripheral chemoreceptors in carotid bodies and
aortic bodies monitor blood
• Central chemoreceptors below medulla oblongata
• Monitor cerebrospinal fluid
• Control respiratory function
• Control blood flow to brain
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Chemoreceptor Reflexes
• Changes in pH, O2, and CO2 concentrations
• Produced by coordinating cardiovascular and
respiratory activities
© 2015 Pearson Education, Inc.
Figure 21-14 The Chemoreceptor Reflexes.
Respiratory centers in
the medulla oblongata
stimulated
Increasing CO2 levels,
decreasing pH
and O2 levels
Effects on
Cardiovascular Center
Reflex Response
Chemoreceptors
stimulated
Respiratory Response
Respiratory rate
increases
Cardiovascular
Responses
Cardioacceleratory
center stimulated
Cardioinhibitory
center inhibited
Vasomotor center
stimulated
Start
Vasoconstriction
occurs
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Increased CO2 levels,
decreased pH and O2
levels in blood and CSF
Decreased CO2 levels,
increased pH and O2
levels in blood and CSF
HOMEOSTASIS
Normal pH, O2,
and CO2 levels in
blood and CSF
© 2015 Pearson Education, Inc.
Increased cardiac
output and blood
pressure
21-3 Cardiovascular Regulation
• CNS Activities and the Cardiovascular Centers
• Thought processes and emotional states can
elevate blood pressure by:
• Cardiac stimulation and vasoconstriction
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Hormones and Cardiovascular Regulation
• Hormones have short-term and long-term effects
on cardiovascular regulation
• For example, E and NE from adrenal medullae
stimulate cardiac output and peripheral
vasoconstriction
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Antidiuretic Hormone (ADH)
• Released by neurohypophysis (posterior lobe of
pituitary)
• Elevates blood pressure
• Reduces water loss at kidneys
• ADH responds to:
• Low blood volume
• High plasma osmotic concentration
• Circulating angiotensin II
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Angiotensin II
• Responds to fall in renal blood pressure
• Stimulates:
•
•
•
•
Aldosterone production
ADH production
Thirst
Cardiac output and peripheral vasoconstriction
© 2015 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Erythropoietin (EPO)
• Released at kidneys
• Responds to low blood pressure, low O2 content in
blood
• Stimulates red blood cell production
© 2015 Pearson Education, Inc.
Figure 21-15a The Hormonal Regulation of Blood Pressure and Blood Volume.
HOMEOSTASIS
Normal blood
pressure and
volume
HOMEOSTASIS
DISTURBED
Start
HOMEOSTASIS
RESTORED
Blood pressure
and volume decrease
Decreasing blood
pressure and
volume
Blood pressure
and volume increase
Short-term
Long-term
Sympathetic activation
and release of adrenal
hormones E and NE
Endocrine Response
of Kidneys
Renin release leads
to angiotensin II
activation
Erythropoietin (EPO)
is released
Increased cardiac
output and
peripheral
vasoconstriction
Angiotensin II Effects
Antidiuretic hormone
released
Aldosterone secreted
Thirst stimulated
a Factors that compensate
for decreased blood
pressure and volume
© 2015 Pearson Education, Inc.
Increased red blood
cell formation
Combined Short-Term
and Long-Term Effects
Increased
blood
pressure
Increased
blood
volume
21-3 Cardiovascular Regulation
• Natriuretic Peptides
• Atrial natriuretic peptide (ANP)
• Produced by cells in right atrium
• Brain natriuretic peptide (BNP)
• Produced by ventricular muscle cells
• Respond to excessive diastolic stretching
• Lower blood volume and blood pressure
• Reduce stress on heart
© 2015 Pearson Education, Inc.
Figure 21-15b The Hormonal Regulation of Blood Pressure and Blood Volume.
Responses to ANP and BNP
Increased Na + loss in urine
Increased water loss in urine
Natriuretic
peptides released
by the heart
Decreased thirst
Combined Effects
Inhibition of ADH, aldosterone,
epinephrine, and
norepinephrine release
Decreased blood
volume
Peripheral vasodilation
HOMEOSTASIS
DISTURBED
HOMEOSTASIS
RESTORED
Increasing blood
pressure and
volume
Decreasing blood
pressure and
volume
HOMEOSTASIS
Increasing blood
pressure and
volume
b Factors that compensate for
increased blood pressure and
volume
© 2015 Pearson Education, Inc.
Normal
blood pressure
and volume
21-4 Cardiovascular Adaptation
• Blood, Heart, and Cardiovascular System
• Work together as unit
• Respond to physical and physiological changes
(for example, exercise and blood loss)
• Maintain homeostasis
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• The Cardiovascular Response to Exercise
• Light Exercise
• Extensive vasodilation occurs, increasing
circulation
• Venous return increases with muscle contractions
• Cardiac output rises
• Venous return (Frank–Starling principle)
• Atrial stretching
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• The Cardiovascular Response to Exercise
• Heavy Exercise
• Activates sympathetic nervous system
• Cardiac output increases to maximum
• About four times resting level
• Restricts blood flow to “nonessential” organs (e.g.,
digestive system)
• Redirects blood flow to skeletal muscles, lungs,
and heart
• Blood supply to brain is unaffected
© 2015 Pearson Education, Inc.
Table 21-2 Changes in Blood Distribution during Exercise.
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Exercise, Cardiovascular Fitness, and Health
• Regular moderate exercise
• Lowers total blood cholesterol levels
• Intense exercise
• Can cause severe physiological stress
© 2015 Pearson Education, Inc.
Table 21-3 Effects of Training on Cardiovascular Performance.
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• The Cardiovascular Response to Hemorrhaging
• Entire cardiovascular system adjusts to:
• Maintain blood pressure
• Restore blood volume
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Short-Term Elevation of Blood Pressure
• Carotid and aortic reflexes
• Increase cardiac output (increasing heart rate)
• Cause peripheral vasoconstriction
• Sympathetic nervous system
• Triggers hypothalamus
• Further constricts arterioles
• Venoconstriction improves venous return
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Short-Term Elevation of Blood Pressure
• Hormonal effects
• Increase cardiac output
• Increase peripheral vasoconstriction (E, NE, ADH,
angiotensin II)
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Shock
• Short-term responses compensate after blood
losses of up to 20 percent of total blood volume
• Failure to restore blood pressure results in shock
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Long-Term Restoration of Blood Volume
• Recall of fluids from interstitial spaces
• Aldosterone and ADH promote fluid retention and
reabsorption
• Thirst increases
• Erythropoietin stimulates red blood cell production
© 2015 Pearson Education, Inc.
Figure 21-16 Cardiovascular Responses to Blood Loss.
HOMEOSTASIS
Normal blood
pressure and
volume
HOMEOSTASIS
DISTURBED
Blood pressure
and volume increase
Extensive bleeding
decreases blood
pressure and volume
Decreasing blood
pressure and
volume
Increase
in blood
volume
Responses
coordinated by the
endocrine system
Responses
directed by the
nervous system
Pain, stress,
anxiety, fear
Long-Term Hormonal Response
Cardiovascular Responses
ADH, angiotensin II, aldosterone,
and EPO released
Peripheral
vasoconstriction;
mobilization of
venous reserve
Stimulation of
baroreceptors and
chemoreceptors
Higher Centers
Stimulation of
cardiovascular
center
© 2015 Pearson Education, Inc.
HOMEOSTASIS
RESTORED
General
sympathetic
activation
Increased
cardiac
output
21-4 Cardiovascular Adaptation
• Vascular Supply to Special Regions
• Through organs with separate mechanisms to
control blood flow
• Three important examples
1. Brain
2. Heart
3. Lungs
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Blood Flow to the Brain
• Is top priority
• Brain has high oxygen demand
• When peripheral vessels constrict, cerebral
vessels dilate, normalizing blood flow
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Stroke
• Also called cerebrovascular accident (CVA)
• Blockage or rupture in a cerebral artery
• Stops blood flow
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Blood Flow to the Heart
• Through coronary arteries
• Oxygen demand increases with activity
• Lactic acid and low O2 levels
• Dilate coronary vessels
• Increase coronary blood flow
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Blood Flow to the Heart
• Epinephrine
• Dilates coronary vessels
• Increases heart rate
• Strengthens contractions
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Heart Attack
• A blockage of coronary blood flow
• Can cause:
•
•
•
•
Angina (chest pain)
Tissue damage
Heart failure
Death
© 2015 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Blood Flow to the Lungs
• Regulated by O2 levels in alveoli
• High O2 content
• Vessels dilate
• Low O2 content
• Vessels constrict
© 2015 Pearson Education, Inc.
21-5 Pulmonary and Systemic Patterns
• Three General Functional Patterns
1. Peripheral artery and vein distribution is the
same on right and left, except near the heart
2. The same vessel may have different names in
different locations
3. Tissues and organs usually have multiple
arteries and veins
• Vessels may be interconnected with anastomoses
© 2015 Pearson Education, Inc.
Figure 21-17 A Schematic Overview of the Pattern of Circulation (Part 1 of 2).
Brain
Upper limbs
Pulmonary
circuit
(veins)
Lungs
LA
Left
ventricle
Systemic
circuit
(arteries)
Kidneys
Spleen
Liver
Digestive
organs
Gonads
Lower limbs
© 2015 Pearson Education, Inc.
Figure 21-17 A Schematic Overview of the Pattern of Circulation (Part 2 of 2).
Brain
Upper limbs
Pulmonary
circuit
(arteries)
Lungs
RA
Systemic
circuit
(veins)
Right
ventricle
Kidneys
Liver
Digestive
organs
Gonads
Lower limbs
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
21-6 The Pulmonary Circuit
• Deoxygenated Blood Arrives at Heart from
Systemic Circuit
• Passes through right atrium and right ventricle
• Enters pulmonary trunk
• At the lungs
• CO2 is removed
• O2 is added
• Oxygenated blood
• Returns to the heart
• Is distributed to systemic circuit
© 2015 Pearson Education, Inc.
21-6 The Pulmonary Circuit
• Pulmonary Vessels
• Pulmonary arteries
• Carry deoxygenated blood
• Pulmonary trunk
• Branches to left and right pulmonary arteries
• Pulmonary arteries
• Branch into pulmonary arterioles
• Pulmonary arterioles
• Branch into capillary networks that surround alveoli
© 2015 Pearson Education, Inc.
21-6 The Pulmonary Circuit
• Pulmonary Vessels
• Pulmonary veins
• Carry oxygenated blood
• Capillary networks around alveoli
• Join to form venules
• Venules
• Join to form four pulmonary veins
• Pulmonary veins
• Empty into left atrium
© 2015 Pearson Education, Inc.
Figure 21-18 The Pulmonary Circuit (Part 1 of 2).
Ascending aorta
Superior vena cava
Right lung
Right
pulmonary
arteries
Right
pulmonary
veins
Inferior vena
cava
Descending
aorta
© 2015 Pearson Education, Inc.
Figure 21-18 The Pulmonary Circuit (Part 2 of 2).
Aortic arch
Pulmonary trunk
Left lung
Left pulmonary
arteries
Left pulmonary
veins
Alveolus
Capillary
O2
Inferior vena
cava
Descending
aorta
© 2015 Pearson Education, Inc.
CO2
21-7 The Systemic Circuit
• The Systemic Circuit
• Contains 84 percent of blood volume
• Supplies entire body
• Except for pulmonary circuit
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Systemic Arteries
• Blood moves from left ventricle
• Into ascending aorta
• Coronary arteries
• Branch from aortic sinus
© 2015 Pearson Education, Inc.
Figure 21-19 An Overview of the Major Systemic Arteries (Part 1 of 2).
Vertebral
Right common carotid
Right subclavian
Left common carotid
Brachiocephalic
trunk
Left subclavian
Axillary
Pulmonary trunk
Descending aorta
Aortic arch
Ascending
aorta
Diaphragm
Celiac trunk
Superior mesenteric
Brachial
Renal
Gonadal
Inferior mesenteric
Common iliac
Radial
Internal iliac
Ulnar
External iliac
Palmar
arches
Deep
femoral
Femoral
© 2015 Pearson Education, Inc.
Figure 21-19 An Overview of the Major Systemic Arteries (Part 2 of 2).
Femoral
Popliteal
Descending
genicular
Posterior tibial
Anterior tibial
Fibular
Dorsalis pedis
Plantar arch
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Aorta
• The ascending aorta
• Rises from the left ventricle
• Curves to form aortic arch
• Turns downward to become descending aorta
© 2015 Pearson Education, Inc.
Figure 21-20 Arteries of the Chest and Upper Limb.
Right thyrocervical trunk
Right vertebral
Supplies muscles,
skin, tissues of neck,
thyroid gland,
shoulders, and upper
back (right side)
Supplies spinal cord,
cervical vertebrae (right
side); fuses with left
vertebral, forming basilar
artery after entering cranium
through foramen magnum
Left
common
carotid
Left
subclavian
Brachiocephalic
trunk
Right subclavian
Right internal thoracic
Right common
carotid
(see Figure 21–
21)
Right
thyrocervical
trunk
Supplies skin and muscles
of chest and abdomen,
mammary gland (right
side), pericardium
Right
vertebral
Right
common
carotid
Left common
carotid
Aortic arch
Thoracoacromial
Left subclavian
Right axillary
Supplies
muscles of the
right pectoral
region and axilla
Ascending aorta
Lateral thoracic
Anterior humeral
circumflex
Thoracic aorta
Posterior humeral
circumflex
LEFT
VENTRICLE
Subscapular
Deep brachial
Intercostals
Right brachial
Supplies structures
of the arm
Right
radial
Right
ulnar
Supplies
forearm,
radial
side
Supplies
forearm,
ulnar
side
Ulnar
collateral
arteries
Abdominal aorta
Anterior ulnar recurrent
Posterior ulnar recurrent
Anterior crural interosseous
The radial and ulnar arteries are
connected by anastomoses of palmar
arches that supply digital arteries
Deep palmar arch
Superficial palmar arch
Digital arteries
© 2015 Pearson Education, Inc.
Thoracic
aorta (see
Figure 21–23)
21-7 The Systemic Circuit
• Branches of the Aortic Arch
• Deliver blood to head, neck, shoulders, and upper
limbs
1. Brachiocephalic trunk
2. Left common carotid artery
3. Left subclavian artery
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Subclavian Arteries
• Leaving the thoracic cavity:
• Become axillary artery in arm
• And brachial artery distally
© 2015 Pearson Education, Inc.
Figure 21-20 Arteries of the Chest and Upper Limb (Part 1 of 2).
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Brachial Artery
• Divides at coronoid fossa of humerus
• Into radial artery and ulnar artery
• Fuse at wrist to form:
• Superficial and deep palmar arches
• Which supply digital arteries
© 2015 Pearson Education, Inc.
Figure 21-20 Arteries of the Chest and Upper Limb (Part 2 of 2).
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Common Carotid Arteries
• Each common carotid divides into:
• External carotid artery – supplies blood to
structures of the neck, lower jaw, and face
• Internal carotid artery – enters skull and delivers
blood to brain
• Divides into three branches
1. Ophthalmic artery
2. Anterior cerebral artery
3. Middle cerebral artery
© 2015 Pearson Education, Inc.
Figure 21-21 Arteries of the Neck and Head (Part 1 of 2).
Anterior cerebral
Middle cerebral
Ophthalmic
Cerebral arterial circle
Carotid canal
Posterior cerebral
Basilar
Internal carotid
Carotid sinus
Vertebral
Inferior thyroid
Thyrocervical
trunk
Transverse cervical
Suprascapular
Subclavian
Axillary
Internal thoracic
Second rib
© 2015 Pearson Education, Inc.
Figure 21-21 Arteries of the Neck and Head (Part 2 of 2).
Branches of the
External Carotid
Superficial
temporal
Maxillary
Occipital
Facial
Lingual
External
carotid
Common carotid
Brachiocephalic
trunk
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Vertebral Arteries
• Also supply brain with blood
• Left and right vertebral arteries
• Arise from subclavian arteries
• Enter cranium through foramen magnum
• Fuse to form basilar artery
• Branches to form posterior cerebral arteries
• Posterior cerebral arteries
• Become posterior communicating arteries
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Anastomoses
• The cerebral arterial circle (or circle of Willis)
interconnects:
• The internal carotid arteries
• And the basilar artery
© 2015 Pearson Education, Inc.
Figure 21-22a Arteries of the Brain.
Cerebral Arterial Circle
Anterior
cerebral
Anterior
communicating
Ophthalmic
Anterior cerebral
Internal
carotid (cut)
Posterior
communicating
Middle
cerebral
Posterior cerebral
Pituitary
gland
Basilar
Posterior
cerebral
Vertebral
Cerebellar
a Inferior surface
© 2015 Pearson Education, Inc.
Figure 21-22b Arteries of the Brain.
Middle
cerebral
Anterior
cerebral
Posterior
cerebral
Ophthalmic
Cerebral arterial
circle
Basilar
Vertebral
Internal carotid
b Lateral view
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Descending Aorta
• Thoracic aorta
• Supplies organs of the chest
•
•
•
•
Bronchial arteries
Pericardial arteries
Esophageal arteries
Mediastinal arteries
• Supplies chest wall
• Intercostal arteries
• Superior phrenic arteries
© 2015 Pearson Education, Inc.
Figure 21-23a Major Arteries of the Trunk (Part 1 of 4).
Aortic arch
Internal thoracic
Thoracic aorta
Somatic Branches of
the Thoracic Aorta
Intercostal arteries
Superior phrenic
Inferior phrenic
a A diagrammatic view, with most of the thoracic
and abdominal organs removed
© 2015 Pearson Education, Inc.
Figure 21-23a Major Arteries of the Trunk (Part 2 of 4).
Visceral Branches of
the Thoracic Aorta
Bronchial arteries
Esophageal arteries
Mediastinal artery
Pericardial artery
a A diagrammatic view, with most of the thoracic
and abdominal organs removed
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Descending Aorta
• Abdominal Aorta
• Divides at terminal segment of the aorta into:
• Left common iliac artery
• Right common iliac artery
• Unpaired branches
• Major branches to visceral organs
• Paired branches
•
•
•
•
© 2015 Pearson Education, Inc.
To body wall
Kidneys
Urinary bladder
Structures outside abdominopelvic cavity
Figure 21-23a Major Arteries of the Trunk (Part 3 of 4).
Diaphragm
Adrenal
Renal
Gonadal
Lumbar
Terminal segment
of the aorta
Common iliac
Median sacral
a A diagrammatic view, with most of the
thoracic and abdominal organs removed
© 2015 Pearson Education, Inc.
Figure 21-23a Major Arteries of the Trunk (Part 4 of 4).
Celiac Trunk
Left gastric
Splenic
Common hepatic
Superior mesenteric
Abdominal aorta
Inferior mesenteric
a A diagrammatic view, with most of the
thoracic and abdominal organs removed
© 2015 Pearson Education, Inc.
Figure 21-24 Arteries Supplying the Abdominopelvic Organs (Part 1 of 2).
Branches of the
Common Hepatic Artery
Hepatic artery proper (liver)
Gastroduodenal (stomach
and duodenum)
Liver
Cystic (gallbladder)
Right gastric (stomach)
Right gastroepiploic
(stomach and duodenum)
Superior pancreaticoduodenal (duodenum)
Ascending colon
Superior Mesenteric
Artery
Pancreas
Inferior pancreaticoduodenal (pancreas and
duodenum)
Middle colic (cut)
(large intestine)
Right colic (large intestine)
Ileocolic (large intestine)
Small intestine
Intestinal arteries (small
Intestine)
Rectum
© 2015 Pearson Education, Inc.
Figure 21-24 Arteries Supplying the Abdominopelvic Organs (Part 2 of 2).
The Celiac Trunk
Common hepatic
Left gastric
Splenic
Spleen
Stomach
Branches of the
Splenic Artery
Left gastroepiploic
(stomach)
Pancreatic
(pancreas)
Pancreas
Inferior Mesenteric
Artery
Left colic (colon)
Sigmoid (colon)
Rectal (rectum)
Small intestine
Sigmoid
colon
Rectum
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Arteries of the Pelvis and Lower Limbs
• Femoral artery
• Deep femoral artery
• Becomes popliteal artery
• Posterior to knee
• Branches to form:
• Posterior and anterior tibial arteries
• Posterior gives rise to fibular artery
© 2015 Pearson Education, Inc.
Figure 21-23b Major Arteries of the Trunk (Part 2 of 2).
Right common iliac
Left common iliac
Pelvis and right lower limb
Pelvis and left lower limb
Right
external
Iliac (see
Figure 21–25)
Right internal iliac
Pelvic muscles, skin,
urinary and reproductive
organs, perineum, gluteal,
region, and medial thigh
Superior gluteal
Hip muscles and joint
Obturator
Ilium, hip and thigh
muscles, hip joint and
femoral head
Left
internal
iliac
Internal pudendal
Lateral rotators of hip;
rectum, anus, perineal
muscles, external genitalia
Lateral sacral
Skin and muscles of sacrum
b A flowchart showing major arteries of the trunk
© 2015 Pearson Education, Inc.
Left
external
iliac
Figure 21-25a Arteries of the Lower Limb (Part 1 of 2).
Common iliac
External iliac
Internal
iliac
Superior gluteal
Lateral
sacral
Inguinal ligament
Internal
pudendal
Obturator
Deep femoral
Medial
femoral
circumflex
Lateral femoral
circumflex
Femoral
Descending
genicular
a Anterior view
© 2015 Pearson Education, Inc.
Figure 21-25a Arteries of the Lower Limb (Part 2 of 2).
Popliteal
Anterior tibial
Posterior
tibial
Fibular
Dorsalis pedis
Medial plantar
Lateral plantar
Dorsal arch
Plantar arch
a Anterior view
© 2015 Pearson Education, Inc.
Figure 21-25b Arteries of the Lower Limb (Part 1 of 2).
Superior gluteal
Right external iliac
Femoral
Internal
pudendal
Deep femoral
Obturator
Lateral
femoral
circumflex
Medial femoral
circumflex
Femoral
Descending genicular
b Posterior view
© 2015 Pearson Education, Inc.
Figure 21-25b Arteries of the Lower Limb (Part 2 of 2).
Popliteal
Anterior
tibial
Posterior
tibial
Fibular
Posterior
tibial
b Posterior view
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Systemic Veins
• Complementary Arteries and Veins
• Run side by side
• Branching patterns of peripheral veins are more
variable
• In neck and limbs
• One set of arteries (deep)
• Two sets of veins (one deep, one superficial)
• Venous system controls body temperature
© 2015 Pearson Education, Inc.
Figure 21-26 An Overview of the Major Systemic Veins (Part 1 of 2).
KEY
Superficial veins
Deep veins
Vertebral
External jugular
Subclavian
Axillary
Cephalic
Internal jugular
Brachiocephalic
Superior vena cava
Brachial
Intercostal veins
Basilic
Inferior vena cava
Hepatic veins
Renal
Median cubital
Gonadal
Radial
Lumbar veins
Median antebrachial
Left and right
common iliac
Ulnar
External iliac
Palmar venous
arches
Digital veins
Internal iliac
Deep
femoral
Femoral
© 2015 Pearson Education, Inc.
Figure 21-26 An Overview of the Major Systemic Veins (Part 2 of 2).
Great saphenous
Femoral
Popliteal
Small saphenous
Fibular
Posterior tibial
Anterior tibial
KEY
Superficial veins
Plantar venous arch
Dorsal venous arch
© 2015 Pearson Education, Inc.
Deep veins
21-7 The Systemic Circuit
• The Superior Vena Cava (SVC)
• Receives blood from the tissues and organs of:
•
•
•
•
•
Head
Neck
Chest
Shoulders
Upper limbs
© 2015 Pearson Education, Inc.
Figure 21-27c Major Veins of the Head, Neck, and Brain.
Superior sagittal sinus
Superficial cerebral veins
Temporal
Inferior sagittal sinus
Deep cerebral
Great cerebral
Cavernous sinus
Straight sinus
Maxillary
Petrosal sinuses
Right transverse sinus
Facial
Occipital sinus
Sigmoid sinus
Occipital
Vertebral
External jugular
Internal jugular
Right subclavian
Clavicle
Right brachiocephalic
Left brachiocephalic
Axillary
Superior vena cava
Internal thoracic
c Veins draining the brain and the superficial
and deep portions of the head and neck.
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Dural Sinuses
• Superficial cerebral veins and small veins of the
brain stem
• Empty into network of dural sinuses
•
•
•
•
•
© 2015 Pearson Education, Inc.
Superior and inferior sagittal sinuses
Petrosal sinuses
Occipital sinus
Left and right transverse sinuses
Straight sinus
Figure 21-27b Major Veins of the Head, Neck, and Brain.
Inferior sagittal
sinus
Superior sagittal
sinus
Great
cerebral
vein
Straight
sinus
Cavernous
sinus
Occipital
sinus
Petrosal sinuses
Right transverse
sinus
Internal jugular
Right
sigmoid sinus
Vertebral vein
b A lateral view of the brain showing
the venous distribution.
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Cerebral Veins
• Great cerebral vein
• Drains to straight sinus
• Other cerebral veins
• Drain to cavernous sinus
• Which drains to petrosal sinus
• Vertebral Veins
• Empty into brachiocephalic veins of chest
© 2015 Pearson Education, Inc.
Figure 21-27a Major Veins of the Head, Neck, and Brain.
Superior sagittal
sinus (cut)
Cavernous sinus
Cerebral veins
Petrosal sinus
Internal jugular
Sigmoid sinus
Cerebellar veins
Transverse sinus
Straight sinus
Occipital sinus
a An inferior view of the brain, showing the venous
distribution. For the relationship of these veins to
meningeal layers, see Figure 14–3, p. 466.
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Superficial Veins of the Head and Neck
• Converge to form:
• Temporal, facial, and maxillary veins
• Temporal and maxillary veins
• Drain to external jugular vein
• Facial vein
• Drains to internal jugular vein
© 2015 Pearson Education, Inc.
Figure 21-27c Major Veins of the Head, Neck, and Brain.
Superior sagittal sinus
Superficial cerebral veins
Temporal
Inferior sagittal sinus
Deep cerebral
Great cerebral
Cavernous sinus
Straight sinus
Maxillary
Petrosal sinuses
Right transverse sinus
Facial
Occipital sinus
Sigmoid sinus
Occipital
Vertebral
External jugular
Internal jugular
Right subclavian
Clavicle
Right brachiocephalic
Left brachiocephalic
Axillary
Superior vena cava
Internal thoracic
c Veins draining the brain and the superficial
and deep portions of the head and neck.
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Veins of the Hand
• Digital veins
• Empty into superficial and deep palmar veins
• Which interconnect to form palmar venous arches
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Veins of the Hand
• Superficial arch empties into:
•
•
•
•
Cephalic vein
Median antebrachial vein
Basilic vein
Median cubital vein
• Deep palmar veins drain into:
• Radial and ulnar veins
• Which fuse above elbow to form brachial vein
© 2015 Pearson Education, Inc.
Figure 21-28 The Venous Drainage of the Abdomen and Chest (Part 3 of 3).
Median cubital
KEY
Cephalic
Superficial veins
Anterior crural
interosseous
Deep veins
Radial
Basilic
Median antebrachial
Ulnar
Palmar venous
arches
Digital veins
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Brachial Vein
• Merges with basilic vein
• To become axillary vein
• Cephalic vein joins axillary vein
• To form subclavian vein
• Merges with external and internal jugular veins
• To form brachiocephalic vein
• Which enters thoracic cavity
© 2015 Pearson Education, Inc.
Figure 21-28 The Venous Drainage of the Abdomen and Chest (Part 2 of 3).
Vertebral
Internal jugular
External jugular
Subclavian
Highest intercostal
Brachiocephalic
Axillary
Cephalic
Accessory hemiazygos
Hemiazygos
Brachial
Intercostal veins
Inferior vena cava
Basilic
Phrenic veins
Adrenal veins
KEY
Superficial veins
Deep veins
Medial
sacral
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Veins of the Thoracic Cavity
• Brachiocephalic vein receives blood from:
• Vertebral vein
• Internal thoracic vein
• The Left and Right Brachiocephalic Veins
• Merge to form the superior vena cava (SVC)
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Tributaries of the Superior Vena Cava
• Azygos vein and hemiazygos vein, which
receive blood from:
• Intercostal veins
• Esophageal veins
• Veins of other mediastinal structures
© 2015 Pearson Education, Inc.
Figure 21-28 The Venous Drainage of the Abdomen and Chest (Part 1 of 3).
Superior
vena cava
Mediastinal
veins
Esophageal
veins
Azygos
Internal
thoracic
Hepatic
veins
Renal veins
Gonadal
veins
Lumbar
veins
Common iliac
Internal iliac
External iliac
KEY
Superficial veins
Deep veins
© 2015 Pearson Education, Inc.
Figure 21-29 Flowchart of Circulation to the Superior and Inferior Venae Cavae (Part 1 of 2).
Right
external
jugular
Right
vertebral
Right
internal
jugular
Collects
blood from
neck, face,
salivary
glands, scalp
Collects
blood from
cranium,
spinal cord,
vertebrae
Collects
blood from
cranium,
face,
and neck
Left
internal
jugular
Right
subclavian
Superficial veins
Deep veins
Right axillary
Right internal
thoracic
Mediastinal
veins
Collects blood
from structures
of anterior
thoracic wall
Collect blood
from the
mediastinum
Right
brachial
Right
cephalic
Right
basilic
Collects
blood from
forearm,
wrist, and
hand
Collects
blood
from lateral
surface
of upper limb
Collects
blood
from medial
surface
of upper limb
Right
radial
Right
ulnar
Radial
side of
forearm
Ulnar
side of
forearm
Venous network
of wrist and hand
© 2015 Pearson Education, Inc.
Interconnected by
median cubital
vein and median
antebrachial
network
Left
external
jugular
Left brachiocephalic
Right brachiocephalic
KEY
Left
vertebral
Superior vena cava
Through
highest
intercostal
vein
Left internal
thoracic
RIGHT
ATRIUM
Azygos
Left axillary
Hemiazygos
Right
intercostal
veins
Esophageal
veins
Left
intercostal
veins
Collect
blood from
vertebrae and
body wall
Collect
blood
from the
esophagus
Collect
blood from
vertebrae and
body wall
Inferior vena cava
Left
subclavian
Collects blood
from veins of
the left upper
limb
21-7 The Systemic Circuit
• The Inferior Vena Cava (IVC)
• Collects blood from organs inferior to the
diaphragm
© 2015 Pearson Education, Inc.
Figure 21-29 Flowchart of Circulation to the Superior and Inferior Venae Cavae (Part 2 of 2).
Inferior vena cava
KEY
Superficial veins
Deep veins
Right external
Iliac (see
Figure 21–30)
Hepatic veins
Phrenic veins
Collect blood from the
liver
Collect blood from
the diaphragm
Gonadal veins
Adrenal veins
Collect blood from the
gonads
Collect blood from
the adrenal glands
Lumbar veins
Renal veins
Collect blood from the
spinal cord and body wall
Collect blood from
the kidneys
Right common iliac
Left common iliac
Right internal iliac
Left internal iliac
Gluteal Internal
veins pudendal
vein
Collects blood
from veins of the
right lower limb
© 2015 Pearson Education, Inc.
Obturator Lateral
sacral
vein
vein
Collect blood from the pelvic muscles,
skin, and urinary and reproductive
organs of the right side of the pelvis
Collects blood from
the left gluteal,
internal pudendal,
obturator, and
lateral sacral veins
Left
external
iliac
Collects blood
from veins of the
left lower limb
21-7 The Systemic Circuit
• Veins of the Foot
• Capillaries of the sole
• Drain into a network of plantar veins
• Which supply the plantar venous arch
• Drain into deep veins of leg:
• Anterior tibial vein
• Posterior tibial vein
• Fibular vein
• All three join to become popliteal vein
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Dorsal Venous Arch
• Collects blood from:
• Superior surface of foot
• Digital veins
• Drains into two superficial veins
1. Great saphenous vein (drains into femoral vein)
2. Small saphenous vein (drains into popliteal
vein)
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Popliteal Vein
• Becomes the femoral vein
• Before entering abdominal wall, receives blood
from:
• Great saphenous vein
• Deep femoral vein
• Femoral circumflex vein
• Inside the pelvic cavity
• Becomes the external iliac vein
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The External Iliac Veins
• Are joined by internal iliac veins
• To form right and left common iliac veins
• The right and left common iliac veins
• Merge to form the inferior vena cava
© 2015 Pearson Education, Inc.
Figure 21-30a Venous Drainage from the Lower Limb.
Common iliac
Internal iliac
Superior gluteal
External iliac
Inferior gluteal
Lateral sacral
Internal pudendal
Obturator
Femoral
Femoral circumflex
Deep femoral
Femoral
Collects blood
from the thigh
Great saphenous
Great saphenous
Collects blood
from the
superficial veins
of the lower limb
Small saphenous
Collects blood
from superficial
veins of the leg
and foot
Popliteal
Small saphenous
Posterior tibial
Fibular
Anterior tibial
Fibular
The dorsal and plantar
venous arches collect blood
from the foot and toes
Dorsal venous arch
Plantar venous arch
Digital
a Anterior view
© 2015 Pearson Education, Inc.
KEY
Superficial veins
Deep veins
Figure 21-30b Venous Drainage from the Lower Limb.
Common iliac
External iliac
Superior gluteal
Inferior gluteal
Internal pudendal
Obturator
Femoral
Femoral circumflex
Deep femoral
Deep femoral
Collects blood
from the thigh
Femoral
Great saphenous
Collects blood
from the
superficial veins
of the lower limb
Small saphenous
Collects blood
from superficial
veins of the leg
and foot
Popliteal
Small saphenous
Anterior tibial
Posterior tibial
Anterior tibial
Fibular
The dorsal and plantar
venous arches collect blood
from the foot and toes
KEY
Superficial veins
Deep veins
Dorsal venous arch
Plantar venous arch
Digital
b Posterior view
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Major Tributaries of the Abdominal Inferior Vena
Cava
1.
2.
3.
4.
5.
6.
Lumbar veins
Gonadal veins
Hepatic veins
Renal veins
Adrenal veins
Phrenic veins
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Hepatic Portal System
• Connects two capillary beds
• Delivers nutrient-laden blood
• From capillaries of digestive organs
• To liver sinusoids for processing
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Tributaries of the Hepatic Portal Vein
1. Inferior mesenteric vein
• Drains part of large intestine
2. Splenic vein
• Drains spleen, part of stomach, and pancreas
3. Superior mesenteric vein
• Drains part of stomach, small intestine, and part of
large intestine
4. Left and right gastric veins
• Drain part of stomach
5. Cystic vein
• Drains gallbladder
© 2015 Pearson Education, Inc.
21-7 The Systemic Circuit
• Blood Processed in Liver
• After processing in liver sinusoids (exchange
vessels):
• Blood collects in hepatic veins and empties into
inferior vena cava
© 2015 Pearson Education, Inc.
Figure 21-31 The Hepatic Portal System (Part 1 of 2).
Inferior vena cava
Hepatic
Liver
Cystic
Hepatic portal
Superior Mesenteric
Vein and Its Tributaries
Pancreas
Pancreaticoduodenal
Middle colic (from
transverse colon)
Right colic (ascending
colon)
Ileocolic (Ileum and
ascending colon)
Intestinal (small intestine)
© 2015 Pearson Education, Inc.
Figure 21-31 The Hepatic Portal System (Part 2 of 2).
Left gastric
Right gastric
Splenic Vein and Its
Tributaries
Stomach
Left gastroepiploic
(stomach)
Spleen
Right gastroepiploic
(stomach)
Pancreatic
Pancreas
Descending colon
Inferior Mesenteric
Vein and Its Tributaries
Left colic (descending
colon)
Sigmoid
(sigmoid colon)
Superior rectal (rectum)
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Fetal and Maternal Cardiovascular Systems
Promote the Exchange of Materials
• Embryonic lungs and digestive tract nonfunctional
• Respiratory functions and nutrition provided by
placenta
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Placental Blood Supply
• Blood flows to the placenta
• Through a pair of umbilical arteries that arise from
internal iliac arteries
• Enters umbilical cord
• Blood returns from placenta
• In a single umbilical vein that drains into ductus
venosus
• Ductus venosus
• Empties into inferior vena cava
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Before Birth
• Fetal lungs are collapsed
• O2 provided by placental circulation
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Fetal Pulmonary Circulation Bypasses
• Foramen ovale
• Interatrial opening
• Covered by valve-like flap
• Directs blood from right to left atrium
• Ductus arteriosus
• Short vessel
• Connects pulmonary and aortic trunks
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Cardiovascular Changes at Birth
• Newborn breathes air
• Lungs expand
•
•
•
•
Pulmonary vessels expand
Reduced resistance allows blood flow
Rising O2 causes ductus arteriosus constriction
Rising left atrium pressure closes foramen ovale
• Pulmonary circulation provides O2
© 2015 Pearson Education, Inc.
Figure 21-32a Fetal Circulation.
Aorta
Foramen ovale (open)
Ductuc arteriosis (open)
Pulmonary trunk
Umbilical
vein
Liver
Ductus
venosus
Placenta
Umbilical
cord
a Blood flow to and from the placenta
in full-term fetus (before birth)
© 2015 Pearson Education, Inc.
Inferior
vena cava
Umbilical
arteries
Figure 21-32b Fetal Circulation.
Ductus arteriosus
(closed)
Pulmonary trunk
Left atrium
Foramen ovale
(closed)
Right atrium
Left ventricle
Inferior
vena cava
Right ventricle
b Blood flow through the neonatal
(newborn) heart after delivery
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 6 of 6).
Normal Heart Structure
Most congenital heart problems result
from abnormal formation of the heart or
problems with the connections between
the heart and the great vessels.
© 2015 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Patent Foramen Ovale and Patent Ductus
Arteriosus
• In patent (open) foramen ovale blood recirculates
through pulmonary circuit instead of entering left
ventricle
• The movement, driven by relatively high systemic
pressure, is a “left-to-right shunt”
• Arterial oxygen content is normal, but left ventricle
must work much harder than usual to provide
adequate blood flow through systemic circuit
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 1 of 6).
Patent Foramen Ovale and Patent Ductus Arteriosus
Patent ductus
arteriosus
Patent
foramen
ovale
© 2015 Pearson Education, Inc.
If the foramen ovale remains open, or patent, blood
recirculates through the pulmonary circuit instead of
entering the left ventricle. The movement, driven by
the relatively high systemic pressure, is called a
“left-to-right shunt.” Arterial oxygen content is
normal, but the left ventricle must work much
harder than usual to provide adequate blood flow
through the systemic circuit. Hence, pressures rise
in the pulmonary circuit. If the pulmonary pressures
rise enough, they may force blood into the
systemic circuit through the ductus arteriosus. This
condition—a patent ductus arteriosus—creates a
“right-to-left shunt.” Because the circulating blood is
not adequately oxygenated, it develops a deep red
color. The skin then develops the blue tones typical of
cyanosis and the infant is known as a “blue baby.”
21-8 Fetal and Maternal Circulation
• Patent Foramen Ovale and Patent Ductus
Arteriosus
• Pressures rise in the pulmonary circuit
• If pulmonary pressures rise enough, they may force
blood into systemic circuit through ductus
arteriosus
• A patent ductus arteriosus creates a “right-to-left
shunt”
• Because circulating blood is not adequately
oxygenated, it develops deep red color
• Skin develops blue tones typical of cyanosis and
infant is known as a “blue baby”
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 2 of 6).
Patent ductus
arteriosus
Pulmonary
stenosis
Ventricular
septal defect
Enlarged
right ventricle
© 2015 Pearson Education, Inc.
Tetralogy of Fallot
The tetralogy of Fallot (fa-LŌ) is a complex
group of heart and circulatory defects that affect
0.10% of newborn infants. In this condition,
(1) the pulmonary trunk is abnormally narrow
(pulmonary stenosis), (2) the interventricular
septum is incomplete, (3) the aorta originates
where the interventricular septum normally ends,
and (4) the right ventricle is enlarged and both
ventricles thicken in response to the increased
workload.
21-8 Fetal and Maternal Circulation
• Tetralogy of Fallot
• Complex group of heart and circulatory defects
that affect 0.10 percent of newborn infants
1. Pulmonary trunk is abnormally narrow (pulmonary
stenosis)
2. Interventricular septum is incomplete
3. Aorta originates where interventricular septum
normally ends
4. Right ventricle is enlarged and both ventricles
thicken in response to increased workload
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 3 of 6).
Ventricular Septal Defect
Ventricular
septal defect
Interventricular
septum
© 2015 Pearson Education, Inc.
A ventricular septal defect is an abnormal opening
in the wall (septum) between the left and right
ventricles. It affects 0.12% of newborns. The
opening between the two ventricles has an
effect similar to a connection between the atria:
When the more powerful left ventricle beats, it
ejects blood into the right ventricle and pulmonary
circuit.
21-8 Fetal and Maternal Circulation
• Ventricular Septal Defect
• Openings in interventricular septum that separate
right and left ventricles
• The most common congenital heart problems,
affecting 0.12 percent of newborns
• Opening between the two ventricles has an effect
similar to a connection between the atria
• When more powerful left ventricle beats, it ejects
blood into right ventricle and pulmonary circuit
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 4 of 6).
Atrioventricular Septal Defect
Atrial
defect
Ventricular
defect
© 2015 Pearson Education, Inc.
In an atrioventricular septal defect, both the atria
and ventricles are incompletely separated. The
results are quite variable, depending on the extent
of the defect and the effects on the atrioventricular
valves. This type of defect most commonly affects
infants with Down’s syndrome, a disorder caused by
the presence of an extra copy of chromosome 21.
21-8 Fetal and Maternal Circulation
• Atrioventricular Septal Defect
• Both the atria and ventricles are incompletely
separated
• Results are quite variable, depending on extent of
defect and effects on atrioventricular valves
• This type of defect most commonly affects infants
with Down’s syndrome, a disorder caused by the
presence of an extra copy of chromosome 21
© 2015 Pearson Education, Inc.
Figure 21-33 Congenital Heart Problems (Part 5 of 6).
Transposition of the Great Vessels
Patent ductus
arteriosus
Aorta
Pulmonary
trunk
© 2015 Pearson Education, Inc.
In the transposition of the great vessels, the
aorta is connected to the right ventricle instead
of to the left ventricle, and the pulmonary artery
is connected to the left ventricle instead of the
right ventricle. This malformation affects 0.05%
of newborn infants.
21-8 Fetal and Maternal Circulation
• Transposition of Great Vessels
• The aorta is connected to right ventricle instead of
to left ventricle
• The pulmonary artery is connected to left ventricle
instead of right ventricle
• This malformation affects 0.05 percent of newborn
infants
© 2015 Pearson Education, Inc.
21-9 Effects of Aging and the Cardiovascular
System
• Cardiovascular Capabilities Decline with Age
• Age-related changes occur in:
• Blood
• Heart
• Blood vessels
© 2015 Pearson Education, Inc.
21-9 Effects of Aging and the Cardiovascular
System
• Three Age-Related Changes in Blood
1. Decreased hematocrit
2. Peripheral blockage by blood clot (thrombus)
3. Pooling of blood in legs
• Due to venous valve deterioration
© 2015 Pearson Education, Inc.
21-9 Effects of Aging and the Cardiovascular
System
• Five Age-Related Changes in the Heart
1.
2.
3.
4.
5.
Reduced maximum cardiac output
Changes in nodal and conducting cells
Reduced elasticity of cardiac (fibrous) skeleton
Progressive atherosclerosis
Replacement of damaged cardiac muscle cells
by scar tissue
© 2015 Pearson Education, Inc.
21-9 Effects of Aging and the Cardiovascular
System
• Three Age-Related Changes in Blood Vessels
1. Arteries become less elastic
• Pressure change can cause aneurysm
2. Calcium deposits on vessel walls
• Can cause stroke or infarction
3. Thrombi can form
• At atherosclerotic plaques
© 2015 Pearson Education, Inc.
21-9 Cardiovascular System Integration
• Many Categories of Cardiovascular Disorders
• Disorders may:
• Affect all cells and systems
• Be structural or functional
• Result from disease or trauma
© 2015 Pearson Education, Inc.
Figure 21-34 diagrams the functional relationships between the cardiovascular system and the other body systems we have studied so far.
SYSTEM INTEGRATOR
Body System
Delivers immune system cells to
injury sites; clotting response seals
breaks in skin surface; carries away
toxins from sites of infection;
provides heat
Provides calcium needed for normal cardiac
muscle contraction; protects blood cells
developing in red bone marrow
Transports calcium and phosphate
for bone deposition; delivers EPO
to red bone marrow, parathyroid
hormone, and calcitonin to
osteoblasts and osteoclasts
Muscular
Stimulation of mast cells produces
localized changes in blood flow and
capillary permeability
Skeletal muscle contractions assist in
moving blood through veins; protects
superficial blood vessels, especially in
neck and limbs
Delivers oxygen and nutrients,
removes carbon dioxide, lactic acid,
and heat during skeletal muscle
activity
Controls patterns of circulation in
peripheral tissues; modifies heart
rate and regulates blood pressure;
releases ADH
Endothelial cells maintain blood–
brain barrier; helps generate CSF
Erythropoietin regulates production
of RBCs; several hormones elevate
blood pressure; epinephrine stimulates
cardiac muscle, elevating heart rate
and contractile force
Distributes hormones throughout
the body; heart secretes ANP
and BNP
Integumentary
Cardivascular System
Page 174
Skeletal
Cardivascular System
Nervous
Skeletal
Integumentary
Body System
Page 285
Nervous
Page 380
Endocrine
Endocrine
Page 558
Page 647
Respiratory
Page 874
Digestive
The most extensive communication
occurs between the cardiovascular and
lymphatic systems. Not only are the two
systems physically interconnected, but
cells of the lymphatic system also move
from one part of the body to another within
the vessels of the cardiovascular system.
we examine the lymphatic system in detail,
including its role in the immune response,
in the next chapter.
Page 824
Page 929
Urinary
The section on vessel
distribution demonstrated
the extent of the anatomical
connections between the
cardiovascular system and other
organ systems. This figure summarizes
some of the physiological relationships
involved.
Lymphatic
The CARDIOVASCULAR
System
Reproductive
Page 1010
Page 1090
© 2015 Pearson Education, Inc.