Harvard-MIT Division of Health Sciences and Technology
HST.542J: Quantitative Physiology: Organ Transport Systems
Instructor: Roger Mark
©Roger G. Mark, 2004
MASSACHUSETTS INSTITUTE OF TECHNOLOGY
Department of Electrical Engineering, Department of Mechanical Engineering, Division of
Biological Engineering, and the Harvard-MIT Division of Health Sciences and Technology
6.022J/2.792J/BEH.371J/HST542J: Quantitative Physiology: Organ Transport Systems
INTRODUCTION: THE FUNCTIONAL ANATOMY OF
THE CARDIOVASCULAR SYSTEM
INTRODUCTION: THE FUNCTIONAL ANATOMY OF
THE CARDIOVASCULAR SYSTEM
A. FUNCTIONS OF THE CIRCULATION
(i) Transport: Supplies nutrients to various cellgroups. Removes wastes; distributes heat.
Most important “nutrient” is oxgen (Figure 1). Other materials: CO2, amino acids,
glucose, fats, hormones, ions, urea, cells, etc.
(ii) Communication: Integrative communication via hormones
(iii) Heat Exchanger: Distributes heat to skin, lungs. Controls dissipation
(iv) Protection: Clotting mechanisms, transport of WBCs, antibodies.
B. COMPONENTS OF THE CARDIOVASCULAR SYSTEM
(i) Major Components: Two pumps in series; major conduits; exchange mechanisms be­
tween intravascular and extra-vascular fluid; reservoirs for fluid storage (Figure 2); fluid
medium (blood). Physical characteristics of elastic arteries, collapsible veins, resistance
vessels.
(ii) Organization: High pressure delivery system, low-pressure capacitance system (Figure
2). Parallel organization of supply routes (Figure 3).
(iii) Some Numbers: Typical Dimensions, velocities, normal values (Tables 1, 2).
(iv) Perfusion and O2 Uptake of representative organs (Figure 4).
C. FUNCTlONAL ANATOMY OF THE HEART
(i) Anatomical Landmarks - to be discussed in Lecture. Use Textbooks for reference.
(ii) The Conduction System
(iii) The Cardiac Cycle (Figure 5) — Pressures, volumes, mechanical events, heart sounds.
Introduction: Functional Anatomy
3
35
Dexter 1951
Douglas 1922
Christiansen 1931
Donald 1955
30
10
5
Cardiac Output (liters/min)
Cardiac Index (liters/min/m2)
25
20
Ca
rd
o
ia c
utp
u
dex
c in
a
i
ard
dc
t an
15
Ox
yge
nc
3
n
tio
mp
u
s
on
2
10
1
Oxygen Consumption (liters/min)
4
15
5
0
0
0
0
200
400
600
800
1000
1200
1400
1600
Work Output During Exercise (kilogram-metersters/min)
Figure 1: Relationship between cardiac output and work output (solid curve) and between oxygen
consumption and work output (dashed curve) during exercise. [Data derived from studies by
Douglas and Haldance (1922); Christensen and Mitteilung (1931); Dexter, Whittenberger, Haynes,
Goodale, Gorlin, and Sawyer (1951); and Donald, Bishop, Cumming, and Wade (1955).] After
Figure 1-1 in Guyton, A., C. Jones, and T. Coleman. Circulatory Physiology: Cardiac Output and
its Regulation. 2nd ed. Philadelphia: W.B.Saunders, 1973.
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Pulmonary Circulation
Systemic Circulation
L eft Pump Windkessel
Vessels
120
Precap.
Capillary
E xchange
Vessels
R esistance
Vessels
Sphincter Section
Postcap. Capacitance
R esistance
Vessels
Vessels
R ight
Pump
Windkessel
Vessels
Precap.
Capillary
E xchange
Vessels
R esistance
Vessels
Venous Compartment
Vessels
Venous Compartment
100 mm Hg
100
mm Hg
Postcap. Capacitance
R esistance
Vessels
80
60
40
25 mm Hg
20
0
“High Pressure” System
“L ow Pressure” System
Control of Systemic Pressure and Flow Distribution
180
300
400
300
Control of B lood Volume and Venous R eturn
3,200
180
4,380
130
110
200
620
A pprox. Volumes (cc.)
Figure 2
Figure by MIT OCW. After B. Folkow and E. Neil, Circulation. Oxford University Press, 1971, pp. 6-7.
Introduction: Functional Anatomy
5
H ead and Neck
A rms
L ungs
B ronchial
R ight A trium
L eft A trium
C oronary
R ight Ventricle
L eft Ventricle
T runk
Hepatic
Splenic
H epatic
Portal
M esenteric
K idney ( afferent)
K idney ( efferent)
Pelvic Organs
L egs
Figure by MIT OCW. After Green, H.D. "Circulation: Physical Principles." in Glasser, O.[ed.],
Medical Physics. Vol. 1. Chicago: The Year Book Publishers, 1949.
Figure 3: Arrangement of the parallel routes by which the circulation passes from the aorta to the
vena cava. Representatives of the different categories of route discussed in the text are indicated.
The Xs indicate the location of control points where arterioles may control the flow. RA, right
atrium; LA, left atrium; RV, right ventricle; LV, left ventricle; PV, portal vein. (from Green, H.D.:
Circulation: Physical Principles, in Glasser, O. [ed.]: Medical Physics, Vol. 1 [Chicago: The Year
Book Publishers, Inc., 1949], p. 210. Original illustration kindly furnished by H.D. Green.)
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6.022j—2004
15%
15 %
25 %
10 %
10 %
10%
10 %
10 %
10%
15%
15%
(a)
5%
40 %
10%
5,000 ml/min.
(b)
250 ml/min.
Kidney
Skin
Brain
Heart
Coronary
Liver
Muscle
Other Viscera
Figure by MIT OCW.
Figure 4: Estimated distributions of cardiac output (A) and oxygen consumption (B) to different
organs of the body in a man at rest. The estimates are very rough, from data taken from many
sources and not very consistent. The kidney is greatly overperfused; the muscles, underperfused.
In exercise the proportion of blood flow to muscle increases enormously, as it does for skin in hot
environments.
Kind of
Vessel
Table 1: Geometry of Mesenteric Vascular Bed of the Dog*
Total
Diameter
CrossLength
Number
(mm)
sectional
(cm)
Area (cm2)
Aorta
Large arteries
Main artery branches
Terminal branches
Arterioles
Capillaries
Venules
Terminal veins
Main venous branches
Large veins
Vena cava
10
3
1
0.6
0.02
0.008
0.03
1
2
6
12
1
40
600
1,800
40,000,000
1,200,000,000
80,000,000
1,800
600
40
1
0.8
3.0
5.0
5.0
125
600
570
30
27
11
1..2
40
20
10
1
0.2
0.1
0.2
1
10
20
40
Total
Volume
(cm3)
30
60
50
25
25
60
110
30
270
220
50
⎫
⎪
⎪
⎪
⎪
⎪
⎬
740
⎪
⎪
⎪
⎪
⎪
⎭
930
*
Data of F. Mall.
Introduction: Functional Anatomy
7
Figure by MIT OCW. After Fig. 4-14 in Berne and Levy, Cardiovascular Physiology.
3rd ed. St. Louis, MO: The C.V. Mosby Co., 1977.
Figure 5: Left atrial, aortic, and left ventricular pressure pulses correlated in time with aortic flow,
ventricular volume, heart sounds, venous pulse, and electrocardiogram for complete cardiac cycle
in the dog. [from R. M. Berne and M. N. Levy, Cardiovascular Physiology (4th edition). The C.
V. Mosby Company, 1998.]
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Cardiac Output:
Table 2: Representative Values for Human Circulation
5 liters/min. (resting)
15-25 liters/min. (exercise)
Heart Rate:
60–80 beats/min. (resting)
120–160 beats/min. (exercise)
Stroke Volume:
70 cc. (resting)
160 cc. (exercise)
Pressures:
Aortic Phasic
Mean
120/80 mmHg
100 mmHg
Pulmonary Artery
Mean
25/10
15
Venous Mean
Intrathoracic
5
–5
1 mmHg = 1330 dynes/cm2
Dimensions (diameters):
Aorta
Medium Artery
Arteriole
Capillary
Vein (medium)
Vena Cava
Red Blood Cell
2.5 cm
0.5 cm
30–60 m
8m
0.5 cm
3.0 cm
7m
Velocities (approximate):
100 cm/sec. peak in aorta
0.5–1 mm/sec. in capillaries
20 cm/sec. in vena cava
Viscosities:
Water
Plasma
Whole blood
1.0 centipoise
1.5 centipoise
4.0 centipoise
(1 centipoise = 10–2 dyne-sec./cm2)
Resistance:
Introduction: Functional Anatomy
Total Pulmonary
Systemic
150 dyne-sec. cm–5
1500 dyne-sec. cm–5
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