© 2012 Pearson Education, Inc.
PowerPoint® Lecture Presentations prepared byJason LaPresLone Star College—North Harris
21Blood Vessels and Circulation
© 2012 Pearson Education, Inc.
An Introduction to Blood Vessels and Circulation
• Learning Outcomes
• 21-1 Distinguish among the types of blood vessels based on their structure and function, and
describe how and where fluid and dissolved materials enter and leave the cardiovascular system.
• 21-2 Explain the mechanisms that regulate blood flow through vessels, describe the factors
that influence blood pressure, and discuss the mechanisms that regulate
movement of fluids between capillaries and interstitial spaces.
© 2012 Pearson Education, Inc.
An Introduction to Blood Vessels and Circulation
• Learning Outcomes
• 21-3 Describe the control mechanisms that regulate blood flow and pressure in tissues, and explain how the activities of the cardiac, vasomotor, and respiratory centers are coordinated to control blood flow through the tissues.
• 21-4 Explain the cardiovascular system’s homeostatic response to exercise and hemorrhaging, and identify the principal blood vessels and functional characteristics of the special circulation to the brain, heart, and lungs.
© 2012 Pearson Education, Inc.
An Introduction to Blood Vessels and Circulation
• Learning Outcomes
• 21-5 Describe the three general functional patterns seen in the pulmonary and systemic
circuits of the cardiovascular system.
• 21-6 Identify the major arteries and veins of the pulmonary circuit.
• 21-7 Identify the major arteries and veins of the systemic circuit.
© 2012 Pearson Education, Inc.
An Introduction to Blood Vessels and Circulation
• Learning Outcomes
• 21-8 Identify the differences between fetal and adult circulation patterns, and describe the
changes in the patterns of blood flow that occur at birth.
• 21-9 Discuss the effects of aging on the cardiovascular system, and give
examples of interactions between the cardiovascular system and other organ systems.
© 2012 Pearson Education, Inc.
An Introduction to Blood Vessels and Circulation
• Blood Vessels
• Are classified by size and histological organization
• Are instrumental in overall cardiovascular regulation
© 2012 Pearson Education, Inc.
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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21-1 Blood Vessels
• The Largest Blood Vessels
• Attach to heart
• Pulmonary trunk
• Carries blood from right ventricle
• To pulmonary circulation
• Aorta
• Carries blood from left ventricle
• To systemic circulation
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21-1 Blood Vessels
• The Smallest Blood Vessels
• Capillaries
• Have small diameter and thin walls
• Chemicals and gases diffuse across walls
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21-1 Blood Vessels
• The Structure of Vessel Walls
• Walls have three layers
1. Tunica intima
2. Tunica media
3. Tunica externa
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21-1 Blood Vessels
• The Tunica Intima (Inner Layer)
• Includes:
• The endothelial lining
• Connective tissue layer
• Internal elastic membrane
• In arteries, is a layer of elastic fibers in outer margin of
tunica intima
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21-1 Blood Vessels
• The Tunica Media (Middle Layer)
• Contains concentric sheets of smooth muscle in loose
connective tissue
• Binds to inner and outer layers
• External elastic membrane of the tunica media
• Separates tunica media from tunica externa
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21-1 Blood Vessels
• The Tunica Externa (Outer Layer)
• Anchors vessel to adjacent tissues in arteries
• Contains collagen fibers
• Elastic fibers
• In veins
• Contains elastic fibers
• Smooth muscle cells
• Vasa vasorum (“vessels of vessels”)
• Small arteries and veins
• In walls of large arteries and veins
• Supply cells of tunica media and tunica externa
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Figure 21-1 Comparisons of a Typical Artery and a Typical Vein
Tunica externa
Tunica media
Tunica intima
Smooth muscle
Internal elasticmembrane
External elastic membrane
Endothelium
ARTERY
Elastic fiber
Lumenof vein
Lumenof artery
Artery and vein LM 60
© 2012 Pearson Education, Inc.
Figure 21-1 Comparisons of a Typical Artery and a Typical Vein
Lumenof vein
Lumenof artery
Artery and vein LM 60
Tunica media
Tunica intima
Smoothmuscle
Endothelium
Tunica externa
VEIN
© 2012 Pearson Education, Inc.
Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
© 2012 Pearson Education, Inc.
Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
© 2012 Pearson Education, Inc.
Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
© 2012 Pearson Education, Inc.
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
Large Vein
Medium-Sized Vein
Venule Arteriole
Muscular Artery
Elastic Artery
Fenestrated Capillary Capillaries Continuous Capillary
Pores
Endothelial cells
Basement membrane Basement membrane
Endothelial cells
Tunica externa
Endothelium
Tunica externa
Tunica media
Endothelium
Tunica intima
Tunica externa
Tunica media
Endothelium
Tunica intima
Internal elasticlayer
Endothelium
Tunicaintima
Tunica media
Tunica externa
Tunica externa
Tunica media
Endothelium
Tunica intima
Smooth muscle cells(Media)
Endothelium
Basement membrane
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Figure 21-2 Histological Structure of Blood Vessels
Large Vein
Medium-Sized Vein
Venule
Tunica externa
Endothelium
Tunica externa
Tunica media
Endothelium
Tunica intima
Tunica externa
Tunica media
Endothelium
Tunica intima
© 2012 Pearson Education, Inc.
Figure 21-2 Histological Structure of Blood Vessels
Arteriole
Muscular Artery
Elastic Artery
Internal elasticlayerEndothelium
Tunicaintima
Tunica media
Tunica externa
Tunica externa
Tunica media
Endothelium
Tunica intima
Smooth muscle cells(Media)
Endothelium
Basement membrane
© 2012 Pearson Education, Inc.
Figure 21-2 Histological Structure of Blood Vessels
Fenestrated Capillary Capillaries Continuous Capillary
Pores
Endothelial cells
Basement membrane Basement membrane
Endothelial cells
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Figure 21-3a A Plaque within an Artery
Tunica externa
Lipid deposits(plaque)
Tunica media
Coronary artery
A cross-sectional viewof a large plaque
LM 6
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Figure 21-3b A Plaque within an Artery
Plaque depositin vessel wall
A section of a coronaryartery narrowed by plaqueformation
© 2012 Pearson Education, Inc.
21-1 Structure and Function of Capillaries
• Capillaries
• Are smallest vessels with thin walls
• Microscopic capillary networks permeate all active
tissues
• Capillary function
• Location of all exchange functions of cardiovascular
system
• Materials diffuse between blood and interstitial fluid
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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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21-1 Structure and Function of Capillaries
• Continuous Capillaries
• Have complete endothelial lining
• Are found in all tissues except epithelia and cartilage
• Functions of continuous capillaries
• Permit diffusion of water, small solutes, and lipid-
soluble materials
• Block blood cells and plasma proteins
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21-1 Structure and Function of Capillaries
• Specialized Continuous Capillaries
• Are in CNS and thymus
• Have very restricted permeability
• For example, the blood–brain barrier
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21-1 Structure and Function of Capillaries
• Fenestrated Capillaries
• Have pores in endothelial lining
• Permit rapid exchange of water and larger solutes
between plasma and interstitial fluid
• Are found in:
• Choroid plexus
• Endocrine organs
• Kidneys
• Intestinal tract
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21-1 Structure and Function of Capillaries
• Sinusoids (Sinusoidal Capillaries)
• Have gaps between adjacent endothelial cells
• Liver
• Spleen
• Bone marrow
• Endocrine organs
• Permit free exchange
• Of water and large plasma proteins
• Between blood and interstitial fluid
• Phagocytic cells monitor blood at sinusoids
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Figure 21-4 Capillary Structure
Basementmembrane
Nucleus
Endothelial cell
Endosomes
Boundarybetween
endothelialcells
Fenestrations,or pores
Boundarybetween
endothelialcells
Basementmembrane
Endosomes
Basementmembrane
Gap betweenadjacent cells
SinusoidFenestrated capillaryContinuous capillary
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Figure 21-4a Capillary Structure
Basementmembrane
Nucleus
Endothelial cell
Boundarybetween
endothelialcells
Endosomes
Basementmembrane
Continuous capillary
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Figure 21-4b Capillary Structure
Basementmembrane
Nucleus
Endothelial cell
Endosomes
Boundarybetween
endothelialcells
Fenestrations,or pores
Basementmembrane
Fenestrated capillary
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Figure 21-4c Capillary Structure
Gap betweenadjacent cells
Sinusoid
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21-1 Structure and Function of Capillaries
• Capillary Beds (Capillary Plexus)
• Connect one arteriole and one venule
• Precapillary Sphincter
• Guards entrance to each capillary
• Opens and closes, causing capillary blood to flow in
pulses
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Figure 21-5a The Organization of a Capillary Bed
Smoothmuscle cells
Collateralarteries
Arteriole
Metarterioles
Thoroughfarechannel
Vein
Venule
Capillaries
Section ofprecapillary
sphincter
Precapillarysphincters
Arteriovenousanastomosis
A typical capillary bed. Solid arrows indicateconsistant blood flow; dashed arrows indicatevariable or pulsating blood flow.
Smallvenule
KEYConsistentblood flowVariableblood flow
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Figure 21-5b The Organization of a Capillary Bed
Capillary bed LM 125
A micrograph of a number of capillary beds.
Capillary beds
Metarterioles
Arteriole
Smallartery
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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 21-6 The Function of Valves in the Venous System
Valve closed
Valve closed
Valve opens abovecontracting muscle
Valve closes belowcontracting muscle
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21-1 Blood Vessels
• The Distribution of Blood
• Heart, arteries, and capillaries
• 30–35% of blood volume
• Venous system
• 60–65%
• 1/3 of venous blood is in the large venous networks
of the liver, bone marrow, and skin
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Figure 21-7 The Distribution of Blood in the Cardiovascular System
Pulm
onar
y ar
terie
s 3%
Large venousnetworks (liver,
bone marrow, skin)21%
Venules andmedium-sized veins
25%
Pulmonary
circuit 9%H
eart 7%
Syste
mic
Pulmonary
capillarie
s 2%
Pulmonary veins 4%
Heart 7%
Aorta 2%Elastic arteries 4%S
ystemic capillaries 7%
Muscular arteries 5%
Arterioles 2%
Large veins18%
Systemic
capillaries 7%
arte
rial
syst
em13
%
Sys
tem
icve
no
us
syst
em64
%
© 2012 Pearson Education, Inc.
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 centers stimulate sympathetic nerves
1. Systemic veins constrict (venoconstriction)
2. Veins in liver, skin, and lungs redistribute venous
reserve
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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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Figure 21-8 An Overview of Cardiovascular Physiology
Cardiac Output
Venous Return
Regulation(Neural and Hormonal)
VenousPressure
Arterial BloodPressure
PeripheralResistance
Capillary Pressure
Capillary exchange
Interstitial fluid
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21-2 Pressure and Resistance
• Pressure (P)
• The heart generates P to overcome resistance
• Absolute pressure is less important than pressure
gradient
• 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
1. Blood pressure (BP)
• Arterial pressure (mm Hg)
2. Capillary hydrostatic pressure (CHP)
• Pressure within the capillary beds
3. 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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Figure 21-9 Factors Affecting Friction and Vascular ResistanceFriction and Vessel Length
Friction and Vessel Diameter
Vessel Length versus Vessel Diameter
Factors Affecting Vascular Resistance
Internal surfacearea 1
Internal surface area 2
Resistance to flow 1Flow 1
Resistance to flow 2
Flow 21/
Greatest resistance,slowest flow near surfaces
Leastresistance,greatest flowat center
Diameter 2 cm
Diameter 1 cm
Resistance to flow 1
Resistance to flow 16
Plaque deposit Turbulence
Turbulence
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Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
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Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
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Table 21-1 Key Terms and Relationships Pertaining to Blood Circulation
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21-2 Pressure and Resistance
• An Overview of Cardiovascular Pressures
• Vessel diameters
• Total cross-sectional areas
• Pressures
• Velocity of blood flow
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Figure 21-10a Relationships among Vessel Diameter, Cross-Sectional Area, Blood Pressure, and Blood Velocity within the Systemic Circuit
Vesseldiameter
(cm)
Vessel diameter
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Figure 21-10b Relationships among Vessel Diameter, Cross-Sectional Area, Blood Pressure, and Blood Velocity within the Systemic Circuit
Total cross-sectional area of vessels
Cross-sectional
area(cm2)
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Figure 21-10c Relationships among Vessel Diameter, Cross-Sectional Area, Blood Pressure, and Blood Velocity within the Systemic Circuit
Average blood pressure
Averageblood
pressure(mm Hg)
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Figure 21-10d Relationships among Vessel Diameter, Cross-Sectional Area, Blood Pressure, and Blood Velocity within the Systemic Circuit
Velocity of blood flow
Velocityof blood
flow(cm/sec)
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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
• Arterial Blood Pressure
• Pulse pressure
• Difference between systolic pressure and diastolic
pressure
• Mean arterial pressure (MAP)
• MAP = diastolic pressure + 1/3 pulse pressure
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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
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21-2 Pressure and Resistance
• Elastic Rebound
• Arterial walls
• Stretch during systole
• Rebound (recoil to original shape) during diastole
• Keep blood moving during diastole
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21-2 Pressure and Resistance
• Pressures in Small Arteries and Arterioles
• Pressure and distance
• MAP and pulse pressure decrease with distance from
heart
• Blood pressure decreases with friction
• Pulse pressure decreases due to elastic rebound
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Figure 21-11 Pressures within the Systemic Circuit
Systolic
Pulsepressure
Diastolic
mm Hg
Mean arterialpressure
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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 21-12 Capillary Filtration
Capillaryhydrostatic
pressure(CHP) Amino acid
Blood protein
Glucose
Ions
Interstitialfluid
Hydrogenbond
Watermolecule
Small solutes
Endothelialcell 2
Endothelialcell 1
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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
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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
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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
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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
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21-2 Pressure and Resistance
• Net Capillary Colloid Osmotic Pressure
• Is the difference between:
1. Blood colloid osmotic pressure (BCOP)
2. Interstitial fluid colloid osmotic pressure (ICOP)
• Pulls water and solutes:
• Into a capillary
• From interstitial fluid
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21-2 Pressure and Resistance
• Net Filtration Pressure (NFP)
• The difference between:
• Net hydrostatic pressure
• Net osmotic pressure
NFP = (CHP – IHP) – (BCOP – ICOP)
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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
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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 21-13 Forces Acting across Capillary Walls
KEY
Arteriole
Filtration
CHP (Capillaryhydrostatic pressure)
Venule
BCOP (Blood colloidosmotic pressure)
NFP (Net filtrationpressure)
24 L/day 20.4 L/dayNo net fluidmovement
Reabsorption
35mmHg
25mmHg
25mmHg
25mmHg
25mmHg
18mmHg
NFP 10 mm Hg NFP 0 NFP 7 mm Hg
CHP BCOPFluid forced
out of capillary
CHP BCOPNo net
movementof fluid
BCOP CHPFluid movesinto capillary
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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
• Fluid moves out of blood
• Builds up in peripheral tissues (edema)
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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:
1. Cardiac output
2. Peripheral resistance
3. Blood pressure
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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
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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
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Figure 21-14 Short-Term and Long-Term Cardiovascular Responses
Autoregulation
Local vasodilatorsreleased
HOMEOSTASISRESTORED
HOMEOSTASIS DISTURBED
HOMEOSTASIS
Local decreasein resistanceand increase inblood flow
Inadequatelocal bloodpressure andblood flow
Normalblood pressure
and volume
• Physical stress (trauma, high temperature)• Chemical changes (decreased O2 or pH, increased CO2 or prostaglandins)• Increased tissue activity
Autoregulation is dueto opening and closing precapillary sphinctersdue to local release ofvasodilator or vasoconstrictorchemicals from the tissue.
Start
© 2012 Pearson Education, Inc.
Figure 21-14 Short-Term and Long-Term Cardiovascular Responses
Central Regulation
Stimulation ofreceptors sensitiveto changes insystemic bloodpressure orchemistry
Endocrine mechanisms
HOMEOSTASISRESTORED
Neuralmechanisms
Activation ofcardiovascularcenters
Stimulationof endocrineresponse
Long-term increasein blood volumeand blood pressure
Short-term elevation of blood pressure bysympatheticstimulation of theheart and peripheralvasoconstriction
Central regulation involves neuroendocrine mechanisms that control the total systemic circulation. This regulation involves both the cardiovascular centers and the vasomotor centers.
If autoregulation is ineffective
© 2012 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
• 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
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Autoregulation of Blood Flow within Tissues
• Adjusted by peripheral resistance while cardiac output
stays the same
• Local vasoconstrictors
• Examples: prostaglandins and thromboxanes
• Released by damaged tissues
• Constrict precapillary sphincters
• Affect a single capillary bed
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Vasomotor Center
1. Control of vasoconstriction • Controlled by adrenergic nerves (NE)
• Stimulates smooth muscle contraction in arteriole walls
2. Control of vasodilation• Controlled by cholinergic nerves (NO)
• Relaxes smooth muscle
• Vasomotor Tone
• Produced by constant action of sympathetic
vasoconstrictor nerves
© 2012 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
© 2012 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)
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Baroreceptor Reflexes
• When blood pressure rises, CV centers:
1. Decrease cardiac output
2. Cause peripheral vasodilation
• When blood pressure falls, CV centers:
1. Increase cardiac output
2. Cause peripheral vasoconstriction
© 2012 Pearson Education, Inc.
Figure 21-15 Baroreceptor Reflexes of the Carotid and Aortic Sinuses
Responses to IncreasedBaroreceptor Stimulation
Baroreceptorsstimulated
HOMEOSTASISDISTURBED
Rising bloodpressure
Cardioinhibitorycenters stimulated
Cardioacceleratorycenters inhibited
Vasomotor centersinhibited
Decreasedcardiacoutput
Vasodilationoccurs
HOMEOSTASISRESTORED
Blood pressuredeclines
HOMEOSTASIS
Normal rangeof bloodpressure
Start
© 2012 Pearson Education, Inc.
Figure 21-15 Baroreceptor Reflexes of the Carotid and Aortic Sinuses
HOMEOSTASIS
Normal rangeof bloodpressure
HOMEOSTASISDISTURBED
HOMEOSTASISRESTORED
Falling bloodpressure
Blood pressurerises
Baroreceptorsinhibited
Vasoconstrictionoccurs
Increasedcardiacoutput
Vasomotor centersstimulated
Cardioacceleratorycenters stimulated
Cardioinhibitorycenters inhibited
Responses to DecreasedBaroreceptor Stimulation
Start
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Chemoreceptor Reflexes
• Changes in pH, O2, and CO2 concentrations
• Produced by coordinating cardiovascular and
respiratory activities
© 2012 Pearson Education, Inc.
Figure 21-16 The Chemoreceptor Reflexes
Increasing CO2 levels,
decreasing pHand O2 levels
Respiratory centers inthe medulla oblongatastimulated
Respiratory rateincreases
Increased cardiacoutput and bloodpressure
Cardioacceleratorycenters stimulated
Cardioinhibitorycenters inhibited
Respiratory Response
CardiovascularResponses
Effects onCardiovascular Centers
Vasomotor centersstimulated
Vasoconstrictionoccurs
Normal pH, O2,
and CO2 levels in
blood and CSF
HOMEOSTASIS
Elevated CO2 levels,
decreased pH and O2
levels in blood and CSF
HOMEOSTASISDISTURBED
Start
Decreased CO2 levels,
increased pH and O2
levels in blood and CSF
HOMEOSTASISRESTORED
Reflex Response
Chemoreceptorsstimulated
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• CNS Activities and the Cardiovascular
Centers
• Thought processes and emotional states can
elevate blood pressure by:
• Cardiac stimulation and vasoconstriction
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
21-3 Cardiovascular Regulation
• Angiotensin II
• Responds to fall in renal blood pressure
• Stimulates:
1. Aldosterone production
2. ADH production
3. Thirst
4. Cardiac output and peripheral vasoconstriction
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-17a The Hormonal Regulation of Blood Pressure and Blood Volume
HOMEOSTASIS
Factors that compensate fordecreased blood pressure andvolume
Increased red bloodcell formation
Thirst stimulated
Antidiuretic hormonereleased
Angiotensin II Effects
Combined Short-Termand Long-Term Effects
Endocrine Responseof Kidneys
Renin release leadsto angiotensin IIactivation
Erythropoietin (EPO)is released
Increased cardiacoutput andperipheralvasoconstriction
Sympathetic activationand release of adrenalhormones E and NE
Long-term
Short-term
Increasedbloodpressure
Increasedbloodvolume
Decreasing bloodpressure and
volume
StartBlood pressureand volume fall
HOMEOSTASISDISTURBED HOMEOSTASIS
RESTORED
Normal bloodpressure and
volume
Blood pressureand volume rise
Aldosterone secreted
Angiotensin II
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Figure 21-17b The Hormonal Regulation of Blood Pressure and Blood Volume
HOMEOSTASIS
Factors that compensate forincreased blood pressure andvolume
Increasing bloodpressure and
volume
HOMEOSTASISRESTORED
Declining bloodpressure and
volume
Normalblood pressure
and volume
HOMEOSTASISDISTURBED
Rising bloodpressure and
volume
Natriureticpeptides releasedby the heart
Increased water loss inurine
Reduced thirst
Inhibition of ADH,aldosterone, epinephrine,and norepinephrinerelease
Peripheral vasodilation
Reduced bloodvolume
CombinedEffects
Increased Na loss inurine
Responses to ANPand BNP
© 2012 Pearson Education, Inc.
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
© 2012 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
1. Venous return (Frank–Starling principle)
2. Atrial stretching
© 2012 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
© 2012 Pearson Education, Inc.
Table 21-2 Changes in Blood Distribution during Exercise
© 2012 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
© 2012 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
Table 21-3 Effects of Training on Cardiovascular Performance
Subject Heart Weight (g)
Stroke Volume (mL)
Heart Rate (BPM)
Cardiac Output (L/min)
Blood Pressure (systolic/ diastolic)
Nonathlete (rest) 300 60 83 5.0 120/80
Nonathlete (maximum)
104 192 19.9 187/75
Trained athlete (rest)
500 100 53 5.3 120/80
Trained athlete (maximum)
167 182 30.4 200/90*
*Diastolic pressures of athletes during maximum activity have not been accurately measured.
© 2012 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• The Cardiovascular Response to Hemorrhaging
• Entire cardiovascular system adjusts to:
• Maintain blood pressure
• Restore blood volume
© 2012 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
© 2012 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)
© 2012 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Shock
• Short-term responses compensate after blood losses
of up to 20% of total blood volume
• Failure to restore blood pressure results in shock
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-18 Cardiovascular Responses to Hemorrhaging and Blood Loss
Normal bloodpressure and
volume
Extensive bleedingreduces bloodpressure andvolume
HOMEOSTASISDISTURBED
Responsescoordinated by theendocrine system
Responsesdirected by thenervous system
Falling bloodpressure and
volume
Long-Term Hormonal Response
ADH, angiotensin II, aldosterone,and EPO released
Blood pressureand volume rise
HOMEOSTASISRESTORED
Cardiovascular Responses
Peripheralvasoconstriction;mobilization ofvenous reserve
Increasedcardiacoutput
Elevationof bloodvolume
Stimulation ofbaroreceptors andchemoreceptorsPain, stress,
anxiety, fear
Higher Centers
Stimulation ofcardiovascularcenters
Generalsympatheticactivation
HOMEOSTASIS
© 2012 Pearson Education, Inc.
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
© 2012 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
© 2012 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Stroke
• Also called cerebrovascular accident (CVA)
• Blockage or rupture in a cerebral artery
• Stops blood flow
© 2012 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
© 2012 Pearson Education, Inc.
21-4 Cardiovascular Adaptation
• Blood Flow to the Heart
• Epinephrine
• Dilates coronary vessels
• Increases heart rate
• Strengthens contractions
© 2012 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
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-19 A Schematic Overview of the Pattern of Circulation
Brain
Upper limbs
Lungs
Pulmonarycircuit(veins)
LA
Leftventricle
Systemiccircuit
(arteries)
Kidneys
Spleen
Digestive organs
Gonads
Lower limbs
Liver
© 2012 Pearson Education, Inc.
Figure 21-19 A Schematic Overview of the Pattern of Circulation
Brain
Upper limbs
Lungs
Pulmonarycircuit
(arteries)
RA
Rightventricle
Systemiccircuit(veins)
Kidneys
Liver Digestive
organs
Gonads
Lower limbs
© 2012 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
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-20 The Pulmonary Circuit
Ascending aorta
Superior vena cava
Right lung
Right pulmonaryarteries
Right pulmonaryveins
Inferior vena cava
Descending aorta
© 2012 Pearson Education, Inc.
Figure 21-20 The Pulmonary Circuit
Aortic arch
Pulmonary trunk
Left lung
Left pulmonaryarteriesLeft pulmonaryveins
Alveolus
Capillary
CO2
O2
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Systemic Circuit
• Contains 84% of blood volume
• Supplies entire body
• Except for pulmonary circuit
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• Systemic Arteries
• Blood moves from left ventricle
• Into ascending aorta
• Coronary arteries
• Branch from aortic sinus
© 2012 Pearson Education, Inc.
Figure 21-21 An Overview of the Major Systemic Arteries
Vertebral
Right subclavian
Brachiocephalictrunk
Ascendingaorta
Aortic arch
Celiac trunkBrachial
Right common carotid
Left common carotid
Left subclavian
Axillary
Pulmonary trunkDescending aorta
Diaphragm
Renal
Superior mesenteric
Gonadal
Inferior mesenteric
Common iliac
Internal iliac
Radial
UlnarExternal
iliac
Femoral
Palmararches Deep
femoral
© 2012 Pearson Education, Inc.
Figure 21-21 An Overview of the Major Systemic Arteries
Femoral
Popliteal
Posterior tibial
Anterior tibial
Fibular
Plantar arch
Descendinggenicular
Dorsalis pedis
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-22a Arteries of the Chest and Upper Limb
SuprascapularThyrocervical trunk
Right subclavian
Axillary
Lateral thoracicAnterior humeral
circumflex
Posterior humeralcircumflex
Subscapular
Deep brachial
Intercostal arteries
Brachial
Ulnar recurrent arteries
Right common carotidLeft common carotidVertebral
Brachiocephalic trunk
Left subclavian
Aortic arch
Ascending aorta
Thoracic aorta
Heart
Internal thoracic
Abdominal aortaUlnar collateral arteries
Thoracoacromial
Arteries of the chest and upperlimb, a diagrammatic view
© 2012 Pearson Education, Inc.
Figure 21-22b Arteries of the Chest and Upper Limb
Right vertebral Rightcommoncarotid
Leftcommoncarotid
Leftvertebral
Leftthyrocervical
trunkLeftsubclavian
Brachiocephalictrunk
Right thyrocervicaltrunk
Rightsubclavian
Right axillary
Right internalthoracic
Leftinternalthoracic Left
axillary
AORTICARCH
ASCENDINGAORTA
THORACICAORTA
(see Fig. 2125)
Leftbrachial
Leftulnar
Leftradial
ABDOMINALAORTA
(see Fig. 2126)
LEFTVENTRICLE
Right brachial
Right radial Right ulnar
Connected by anastomosesof palmar arches that supply
digital arteries
To structures of thearm
Forearm,radial side
Forearm,ulnar side
Muscles of the rightpectoral region andaxilla
Skin and muscles ofchest and abdomen,mammary gland (rightside), pericardium
Spinal cord, cervical vertebrae(right side); fuses with left vertebral,forming basilar artery after enteringcranium via foramen magnum
Muscles, skin, tissues of neck, thyroid gland, shoulders, and upper back (right side)
A flowchart of the arteries of the chest and upper limb
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Subclavian Arteries
• Leaving the thoracic cavity:
• Become axillary artery in arm
• And brachial artery distally
© 2012 Pearson Education, Inc.
Figure 21-22a Arteries of the Chest and Upper Limb
SuprascapularThyrocervical trunk
Right subclavian
Axillary
Lateral thoracicAnterior humeral
circumflex
Posterior humeralcircumflex
Subscapular
Deep brachial
Intercostal arteries
Brachial
Ulnar recurrent arteries
Right common carotidLeft common carotidVertebral
Brachiocephalic trunk
Left subclavian
Aortic arch
Ascending aorta
Thoracic aorta
Heart
Internal thoracic
Abdominal aortaUlnar collateral arteries
Thoracoacromial
Arteries of the chest and upperlimb, a diagrammatic view
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-22a Arteries of the Chest and Upper Limb
Arteries of the chest and upperlimb, a diagrammatic view
Radial
Anterior cruralinterosseous
Ulnar
Deep palmararchSuperficialpalmar arch
Digital arteries
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-23 Arteries of the Neck and Head
Second rib
Internal thoracicAxillary
Subclavian
SuprascapularTransverse cervical
Thyrocervicaltrunk
Carotid sinusVertebral
Internal carotid
Inferior thyroid
Basilar
Posterior cerebral
Carotid canal
Cerebral arterial circle
OphthalmicMiddle cerebral
Anterior cerebral
ClavicleFirst rib
© 2012 Pearson Education, Inc.
Figure 21-23 Arteries of the Neck and Head
Branches of theExternal CarotidSuperficialtemporal
Maxillary
Occipital
Facial
LingualExternalcarotid
Common carotid
Brachiocephalictrunk
ClavicleFirst rib
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-24a Arteries of the Brain
Anteriorcerebral
Ophthalmic
Internalcarotid (cut)
Middlecerebral
Pituitarygland
Posteriorcerebral
Cerebellar
Anterior communicating
Cerebral Arterial Circle
Anterior cerebral
PosteriorcommunicatingPosterior cerebral
Basilar
Vertebral
Inferior surface
© 2012 Pearson Education, Inc.
Figure 21-24b Arteries of the Brain
Middlecerebral
Anteriorcerebral
OphthalmicCerebral arterialcircle
Internal carotid
Lateral view
Posteriorcerebral
Basilar
Vertebral
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-25a Major Arteries of the Trunk
Aortic arch
Internal thoracic
Thoracic aorta
Somatic Branches ofthe Thoracic Aorta
Intercostal arteries
Superior phrenic
Inferior phrenic
A diagrammatic view, with most of the thoracic and abdominal organs removed
© 2012 Pearson Education, Inc.
Figure 21-25a Major Arteries of the Trunk
Visceral Branches ofthe Thoracic Aorta
Bronchial arteries
Esophageal arteries
Mediastinal arteries
Pericardial arteries
A diagrammatic view, with most of the thoracic and abdominal organs removed
© 2012 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
• To body wall
• Kidneys
• Urinary bladder
• Structures outside abdominopelvic cavity
© 2012 Pearson Education, Inc.
Figure 21-25a Major Arteries of the Trunk
A diagrammatic view, with most of the thoracic and abdominal organs removed
Diaphragm
Adrenal
Renal
Gonadal
Lumbar
Terminal segmentof the aorta
Common iliac
Median sacral
© 2012 Pearson Education, Inc.
Figure 21-25a Major Arteries of the Trunk
Celiac Trunk
Left gastric
Splenic
Common hepatic
Superior mesenteric
Abdominal aorta
Inferior mesenteric
A diagrammatic view, with most of the thoracic and abdominal organs removed
© 2012 Pearson Education, Inc.
Figure 21-26 Arteries Supplying the Abdominopelvic Organs
Branches of theCommon Hepatic Artery
Hepatic artery proper (liver)
Gastroduodenal (stomachand duodenum)
Cystic (gallbladder)
Right gastric (stomach)
Right gastroepiploid(stomach and duodenum)
Superior pancreatico-duodenal (duodenum)
Ascending colon
Superior MesentericArtery
Inferior pancreatico-duodenal (pancreas and
duodenum)Middle colic (cut)
(large intestine)Right colic (large intestine)
Ileocolic (large intestine)
Intestinal arteries (small intestine)
Liver
Pancreas
Small intestine
Rectum
© 2012 Pearson Education, Inc.
Figure 21-26 Arteries Supplying the Abdominopelvic Organs
Stomach
The Celiac Trunk
Common hepatic
Left gastric
Splenic
Spleen
Branches of theSplenic Artery
Left gastroepiploic(stomach)
Pancreatic(pancreas)
Inferior MesentericArtery
Left colic (colon)
Sigmoid (colon)
Rectal (rectum)
Sigmoid colon
Rectum
Small intestine
Pancreas
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-25b Major Arteries of the Trunk
A flowchart showing major arteries of the trunk
Leftcommoniliac
Pelvis andleft lowerlimb
Pelvis and rightlowerlimb
Right commoniliac
Right externaliliac
Leftinternaliliac
Left externaliliac
Rightinternaliliac
Superiorgluteal
Obturator
Internalpudendal
Lateralsacral
Lateral rotators ofhip; rectum, anus,perineal muscles,external genitaliaIlium, hip
and thighmuscles, hipjoint andfemoral head
Hip muscles,hip joint
Pelvic muscles, skin,viscera of pelvis (urinaryand reproductive organs),perineum, gluteal region,and medial thigh
Skin andmuscles ofsacrum
© 2012 Pearson Education, Inc.
Figure 21-27a Arteries of the Lower Limb
Commoniliac
Externaliliac
Superiorgluteal
Inguinalligament
Deepfemoral
Lateralfemoral
circumflex
Medialfemoralcircumflex
Femoral
InternaliliacLateralsacral
Internalpudendal
Obturator
Descendinggenicular
Anterior view
© 2012 Pearson Education, Inc.
Figure 21-27a Arteries of the Lower Limb
Anterior view
Popliteal
Anterior tibial
Posteriortibial
Fibular
Dorsalis pedis
Medial plantar
Lateral plantarDorsal arch
Plantar arch
© 2012 Pearson Education, Inc.
Figure 21-27b Arteries of the Lower Limb
Posterior view
Medialfemoral
circumflex
Femoral
Internalpudendal
Obturator
Superior gluteal
Right externaliliac
Deep femoral
Lateral femoralcircumflex
Descendinggenicular
© 2012 Pearson Education, Inc.
Figure 21-27b Arteries of the Lower Limb
Posterior view
Popliteal
Anterior tibial
Posteriortibial
Fibular
© 2012 Pearson Education, Inc.
Figure 21-27c Arteries of the Lower Limb
Deepfemoral
Femoral
Descendinggenicular
Popliteal
Fibular Posteriortibial
Anteriortibial
Medialfemoral
circumflex
Lateralfemoral
circumflex
Thigh
Hip joint, femoral head, deepmuscles of the thigh
Skin of leg,knee joint
Leg andfootQuadriceps
musclesAdductor muscles,obturator muscles,hip joint
Connected by anastomoses ofdorsalis pedis, dorsal arch, andplantar arch, which supply distalportions of the foot and the toes
EXTERNAL ILIAC
A flowchart of blood flow to a lower limb
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-28 An Overview of the Major Systemic Veins
VertebralExternal jugular Internal jugular
Brachiocephalic
Superior vena cava
Intercostal veins
Inferior vena cavaRenalGonadal
Subclavian
Axillary
Brachial
Basilic
Hepatic veins
Median cubital
Radial
Ulnar
Median antebrachial
Palmar venous arches
Digital veins
Lumbar veins
Left and rightcommon iliac
External iliacInternal iliac
Deepfemoral
Femoral
Superficial veinsDeep veins
KEY
© 2012 Pearson Education, Inc.
Figure 21-28 An Overview of the Major Systemic Veins
Superficial veinsDeep veins
KEY
Femoral
Posterior tibial
Anterior tibial
Great saphenous
Popliteal
Small saphenous
Fibular
Plantar venous archDorsal venous arch
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Superior Vena Cava (SVC)
• Receives blood from the tissues and organs of:
• Head
• Neck
• Chest
• Shoulders
• Upper limbs
© 2012 Pearson Education, Inc.
Figure 21-29c Major Veins of the Head, Neck, and Brain
Superior sagittal sinus
Superficial cerebral veins
Inferior sagittal sinus
Great cerebralStraight sinus
Petrosal sinusesRight transverse sinus
Occipital sinus
Sigmoid sinus
Occipital
TemporalDeep cerebral
Cavernous sinusMaxillary
Facial
Vertebral
External jugular
Right subclavian
Axillary
Clavicle
First rib
Veins draining the brain and the superficialand deep portions of the head and neck.
Internal jugular
Right brachiocephalic
Left brachiocephalic
Superior vena cavaInternal thoracic
© 2012 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
• Superior and inferior sagittal sinuses
• Petrosal sinuses
• Occipital sinus
• Left and right transverse sinuses
• Straight sinus
© 2012 Pearson Education, Inc.
Figure 21-29b Major Veins of the Head, Neck, and Brain
Straightsinus
Occipitalsinus
Right transversesinus Right
sigmoid sinus
Inferior sagittalsinus
Superior sagittalsinus
Greatcerebral
vein
Cavernoussinus
Petrosal sinusesInternal jugularVertebral vein
A lateral view of the brainshowing the venousdistribution.
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-29a Major Veins of the Head, Neck, and Brain
An inferior view of the brain, showing the venous distribution.
Occipital sinus
Straight sinus
Transverse sinus
Cerebellar veins
Sigmoid sinus
Internal jugular
Cerebral veins
Cavernous sinus
Petrosal sinus
Superior sagittal,sinus (cut)
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-29c Major Veins of the Head, Neck, and Brain
Superior sagittal sinus
Superficial cerebral veins
Inferior sagittal sinus
Great cerebralStraight sinus
Petrosal sinusesRight transverse sinus
Occipital sinus
Sigmoid sinus
Occipital
TemporalDeep cerebral
Cavernous sinusMaxillary
Facial
Vertebral
External jugular
Right subclavian
Axillary
Clavicle
First rib
Veins draining the brain and the superficialand deep portions of the head and neck.
Internal jugular
Right brachiocephalic
Left brachiocephalic
Superior vena cavaInternal thoracic
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-30 The Venous Drainage of the Abdomen and Chest
Palmar venousarches
Digital veins
Ulnar
Median antebrachialRadial
Cephalic
Anterior crural interosseous
Basilic
Median cubital
Deep veins
Superficial veinsKEY
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-30 The Venous Drainage of the Abdomen and Chest
Deep veins
Superficial veinsKEY
Adrenal veinsPhrenic veins
Basilic
INFERIOR VENA CAVA
Intercostal veins
HemiazygosAccessory hemiazygos
CephalicAxillaryBrachiocephalicHighest intercostalSubclavian
External jugularInternal jugularVertebral
Brachial
© 2012 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)
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• Tributaries of the Superior Vena Cava
• Azygos vein and hemiazygos vein, which receive
blood from:
1. Intercostal veins
2. Esophageal veins
3. Veins of other mediastinal structures
© 2012 Pearson Education, Inc.
Figure 21-30 The Venous Drainage of the Abdomen and Chest
Medial sacralDeep veinsSuperficial veins
KEY External iliacInternal iliac
Common iliac
Lumbarveins
Gonadalveins
Renal veins
Hepaticveins
Internalthoracic
Azygos
Esophagealveins
Mediastinalveins
SUPERIORVENA CAVA
© 2012 Pearson Education, Inc.
Figure 21-31a Flowcharts of Circulation to the Superior and Inferior Venae Cavae
Tributaries of the superior vena cava
Rightvertebral
Collect bloodfrom vertebraeand body wall
Left intercostalveins
Hemiazygos
Left brachiocephalic
Collects blood from cranium, face,and neck
Collect blood from structuresof anteriorthoracic wall
Left internal jugular
Right internal jugular
Left andright internalthoracicveins
Esophagealveins
Azygos
Collect blood from the mediastinum
Right external jugular
Rightsubclavian
Rightaxillary
Mediastinalveins
Rightbrachiocephalic
Veins of theright upper
limb
Rightintercostalveins
Collect blood from vertebraeand body wall
Collect blood from theeophagus
KEYSuperficial veinsDeep veins
SUPERIORVENA CAVA
RIGHTATRIUM
Collects blood from cranium, spinalcord, vertebrae
Leftvertebral
Through highestintercostal vein
© 2012 Pearson Education, Inc.
Figure 21-31a Flowcharts of Circulation to the Superior and Inferior Venae Cavae
Tributaries of the superior vena cava
KEYSuperficial veinsDeep veins
Venous networkof wrist and hand
Left cephalic Left basilic
Left axillary
Left brachial
Left subclavian
Left brachiocephalic
Left external jugular
Leftulnar
Leftradial
Radialside offorearm
Ulnarside offorearm
Collects bloodfrom lateral surfaceof upper limb
Collects bloodfrom medial surfaceof upper limb
Collects blood from forearm, wrist, and hand
Collects blood from neck, face, salivaryglands, scalp
Interconnected by mediancubital vein and median
antebrachial network
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• The Inferior Vena Cava (IVC)
• Collects blood from organs inferior to the
diaphragm
© 2012 Pearson Education, Inc.
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
© 2012 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)
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-32a Venous Drainage from the Lower Limb
External iliacCommon iliacInternal iliac
GlutealInternal pudendal
Lateral sacralObturatorFemoral
Femoral circumflex
Deep femoral
Femoral
Great saphenous
Popliteal
Smallsaphenous
Anterior tibial
Posterior tibial
Fibular
Dorsal venous arch
Plantar venous archDigital
An anterior view
© 2012 Pearson Education, Inc.
Figure 21-32b Venous Drainage from the Lower Limb
External iliac
Gluteal
Internal pudendal
ObturatorFemoral
Femoral circumflex
Deep femoral
Femoral
Great saphenous
Popliteal
Smallsaphenous
Anterior tibial
Posterior tibial
Fibular
A posterior view
© 2012 Pearson Education, Inc.
Figure 21-32c Venous Drainage from the Lower Limb
EXTERNAL ILIAC
Smallsaphenous
Femoral
Popliteal
FibularPosterior
tibialAnterior
tibial
Extensive anastomoses interconnectveins of the ankle and foot
Greatsaphenous
KEYSuperficial veinsDeep veins
Collects bloodfrom thesuperficial veinsof the lower limb
Collects bloodfrom the thigh
Collects bloodfrom superficialveins of the legand foot
A flowchart of venous circulation from a lower limb
Deepfemoral
© 2012 Pearson Education, Inc.
21-7 The Systemic Circuit
• Major Tributaries of the Abdominal Inferior Vena
Cava
1. Lumbar veins
2. Gonadal veins
3. Hepatic veins
4. Renal veins
5. Adrenal veins
6. Phrenic veins
© 2012 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
© 2012 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
• Cystic vein
• Drains gallbladder
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-33 The Hepatic Portal System
Inferior vena cava
Hepatic
Cystic
Hepatic portal
Pancreaticoduodenal
Superior MesentericVein and Its Tributaries
Middle colic (fromtransverse colon)
Right colic (ascendingcolon)
Ileocolic (Ileum andascending colon)
Intestinal (small intestine)
Pancreas
Liver
© 2012 Pearson Education, Inc.
Figure 21-33 The Hepatic Portal System
Left gastric
Right gastric
Stomach
Spleen
Pancreas
Left gastroepiploic(stomach)Right gastroepiploic(stomach)Pancreatic
Descending colon
Splenic Vein and ItsTributaries
Inferior MesentericVein and Its Tributaries
Left colic (descendingcolon)Sigmoid(sigmoid colon)
Superior rectal (rectum)
© 2012 Pearson Education, Inc.
Figure 21-31b Flowcharts of Circulation to the Superior and Inferior Venae Cavae
Tributaries of the inferior vena cava
Superiorglutealveins
Internalpudendal
veins
Obturatorveins
Lateralsacralveins
Blood fromveins in leftlower limb
Leftexternal
iliacLeft internal
iliac
Rightexternal
iliacRight internal
iliac
Blood fromveins in right
lower limb
Rightcommon
iliac
Leftcommon
iliac
Collect blood from the pelvic muscles,skin, urinary and reproductive organsof pelvic cavity
Collect blood fromthe kidneys
Collect blood fromthe diaphragm
Collect blood fromthe adrenalglands
Collect blood fromthe spinal cordand body wall
Collect blood fromthe liver
Collect blood fromthe gonads (testesor ovaries)
Hepaticveins
Gonadalveins
Lumbarveins
Phrenicveins
Adrenalveins
Renalveins
RIGHTATRIUM
INFERIORVENA CAVA
KEYSuperficial veinsDeep veins
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
21-8 Fetal and Maternal Circulation
• Before Birth
• Fetal lungs are collapsed
• O2 provided by placental circulation
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-34a Fetal Circulation
Placenta
AortaForamen ovale (open)
Ductus arteriosus (open)
Pulmonary trunk
Liver Inferiorvena cavaDuctusvenosus
Umbilicalvein
Umbilical cord
Blood flow to and from the placenta in full-term fetus (before birth)
Umbilicalarteries
© 2012 Pearson Education, Inc.
Figure 21-34b Fetal Circulation
Blood flow through theneonatal (newborn) heartafter delivery
Inferiorvena cava
Right ventricle
Left ventricle
Right atrium
Foramen ovale(closed)
Left atrium
Pulmonary trunk
Ductus arteriosus(closed)
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
Normal Heart StructureMost heart problems reflect deviations from the normal formation of the heart and its connections to the great vessels.
© 2012 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
© 2012 Pearson Education, Inc.
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”
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
Patent Foramen Ovale and Patent Ductus ArteriosusIf the foramen ovale remains open, or patent,blood recirculates through the pulmonary circuit instead of entering the left ventricle. Themovement, driven by the relatively highsystemic 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.”
Patent ductusarteriosus
Patentforamen
ovale
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
Tetralogy of Fallotventricle is enlarged and both ventricles thicken in response to the increased workload.
The tetralogy of Fallot (fa-LO) is a complexgroup of heart and circulatory defects thataffect 0.10 percent of newborn infants. In thiscondition, (1) the pulmonary trunk is abnor-mally narrow (pulmonary stenosis), (2) the interventricular septum is incomplete, (3) the aorta originates where the interventricularseptum normally ends, and (4) the right
¯Patent ductus
arteriosusPulmonary
stenosisVentricular
septal defectEnlarged
right ventricle
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
Ventricular Septal DefectVentricular septal defects are openings in the inter-ventricular septum that separate the right and left ven-tricles. These defects are the most common congenital heart problems, affecting 0.12 percent of newborns. The opening between the two ventricles has an effect simi-lar to a connection between the atria: When the more powerful left ventricle beats, it ejects blood into the right ventricle and pulmonary circuit.
Ventricularseptal defect
Ventricularseptum
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
In an atriovenricular septal defect, both the atria andventricles are incompletely separated. The results arequite variable, depending on the extent of the defectand 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.
Atrioventricular Septal Defect
Atrialdefect
Ventriculardefect
© 2012 Pearson Education, Inc.
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
© 2012 Pearson Education, Inc.
Figure 21-35 Congenital Heart Problems
In the transposition of great vessels, theaorta is connected to the right ventricleinstead of to the left ventricle, and thepulmonary artery is connected to the leftventricle instead of the right ventricle. This malformation affects 0.05 percent ofnewborn infants.
Transposition of the Great VesselsPatent ductus
arteriosusAorta
Pulmonarytrunk
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
21-9 Effects of Aging and the Cardiovascular System
• Five Age-Related Changes in the Heart
1. Reduced maximum cardiac output
2. Changes in nodal and conducting cells
3. Reduced elasticity of cardiac (fibrous) skeleton
4. Progressive atherosclerosis
5. Replacement of damaged cardiac muscle cells by
scar tissue
© 2012 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
© 2012 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
© 2012 Pearson Education, Inc.
Figure 21-36 System Integrator: The Cardiovascular System
S Y S T E M I N T E G R A T O RBody System Cardiovascular System Body SystemCardiovascular System
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The section on vesseldistribution demonstrated theextent of the anatomicalconnections between thecardiovascular system and otherorgan systems. This figuresummarizes some of the physiologicalrelationships involved.
The most extensive communicationoccurs between the cardiovascular andlymphatic systems. Not only are the twosystems physically interconnected, butcells of the lymphatic system also movefrom one part of the body to anotherwithin the vessels of the cardiovascularsystem. We examine the lymphaticsystem in detail, including its role in theimmune response, in the next chapter.
The CARDIOVASCULAR System
Stimulation of mast cells produceslocalized changes in blood flow andcapillary permeability
Provides calcium needed for normalcardiac muscle contraction; protectsblood cells developing in red bonemarrow
Skeletal muscle contractions assist inmoving blood through veins; protectssuperficial blood vessels, especiallyin neck and limbs
Controls patterns of circulation in peripheral tissues; modifies heartrate and regulates blood pressure;releases ADH
Erythropoietin regulates productionof RBCs; several hormones elevateblood pressure; epinephrinestimulates cardiac muscle, elevatingheart rate and contractile force
Distributes hormones throughoutthe body; heart secretes ANP andBNP
Endothelial cells maintainblood—brain barrier; helpsgenerate CSF
Delivers oxygen and nutrients,removes carbon dioxide, lacticacid, and heat during skeletalmuscle activity
Transports calcium and phosphatefor bone deposition; delivers EPO tored bone marrow, parathyroidhormone, and calcitonin toosteoblasts and osteoclasts
Delivers immune system cells toinjury sites; clotting response sealsbreaks in skin surface; carries awaytoxins from sites of infection;provides heat
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