Comprehensive Physiology Wiley Online Library

Vascular Mechanics

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 Behavior of Arteries in Vivo
2 Circumferential Properties of Arteries
2.1 Relaxed Arteries
2.2 Contracted Arteries
3 Longitudinal Properties of Arteries
3.1 Elastic Characteristics
3.2 Intimal Shear Stresses
4 Radial Properties of Arteries
4.1 Elastic Characteristics
4.2 Mechanics and Wall Nutrition
5 Special Aspects of Vascular Mechanics
5.1 Baroreceptors
5.2 Arteries of Hypertensive Subjects
5.3 Atherosclerotic Arteries
6 Multidirectional Properties of Arteries
6.1 Analytic Assumptions
6.2 Incremental Analysis
6.3 Finite‐Deformation Analysis
Figure 1. Figure 1.

Diagram of arterial segment illustrating circumferential (θ), longitudinal (z), and radial (r) directions. Strains and stresses in θ and z directions are tensile because tissue is stretched in these directions with pressurization. Strains and stresses in z direction also are tensile because vessels are elongated at in situ length. Strains and stresses in r direction are compressive because wall becomes thinner with pressurization.

From Dobrin
Figure 2. Figure 2.

A: simultaneous pressure (P) and diameter (D) recordings of right common carotid artery of 68‐yr‐old male patient during operation. Catheter‐tip manometer inserted through side branch into artery recorded P; a noncontact photoelectric gauge with 2 photocells measured D. Recordings illustrate close correspondence between changes in P and D. B: 3 P‐D loops from 64‐yr‐old male patient during operation. Upper limbs correspond to rising phases of arterial pressure cycle. Lower limbs correspond to falling phases. Note dicrotic notch in lower limb. As pulse pressure increased from 30 mmHg (left) to 99 mmHg (right), width of hysteresis loop increased. As mean pressure and pulse pressure increased, curvilinear character of P‐D curve also became evident.

From Busse et al.
Figure 3. Figure 3.

Size and composition of components of vascular tree. End., endothelium; Ela., elastin; Mus., smooth muscle; Fib., fibrous connective tissue—i.e., collagen.

From Burton
Figure 4. Figure 4.

Free‐body diagram of cylindrical segment of blood vessel at equilibrium illustrating circumferential forces. PT, transmural pressure; σθ, circumferential stress; l, vessel length; h, wall thickness; di, internal diameter.

Figure 5. Figure 5.

Distribution of stresses (σ) across artery wall in circumferential (σθ), longitudinal (σz), and radial (σr) directions. Data computed assuming a homogeneous artery wall. Stresses are greatest at lumen and decline curvilinearly across wall thickness; θ and z stresses are tensile and remain positive at all points across wall; σr is compressive and plotted with a negative sign. Unlike σθ and σz, σr vanishes at outer edge of wall. At lumen σr, is equal in magnitude to transmural pressure; σθ and σz are 10–20 times larger in magnitude. Data are for transmural pressure of 150 cmH2O in relaxed vessel, but proportional values have been reported for both contracted and relaxed vessels over a wide range of pressures .

From Vaishnav et al. , by permission of the American Heart Association, Inc
Figure 6. Figure 6.

Stress‐strain relations of dog carotid artery after exciting vascular muscle with supramaximal doses of norepinephrine (NE) and after inactivating vascular muscle with supramaximal doses of potassium cyanide (KCN). Difference between NE and KCN curves gives length‐active stress relationship for vascular muscle. Behavior after treatment with KCN gives stress‐strain relationship for connective tissue. Strain (Δr/r0) is the fractional increase in circumferential length, a measure of circumferential deformation.

From Dobrin and Rovick
Figure 7. Figure 7.

Isometric and isobaric contraction of vascular smooth muscle. A: polygraph record of artery 1st undergoing isometric contraction [pressure (PT) was elevated just enough to maintain vessel diameter constant]. Maintaining isometric contraction required 150‐mmHg increase in PT, which then was reduced to preexcitation levels to permit isobaric contraction. This caused 25% reduction in diameter {Δd). B: summary of pressure‐strain data for 160 arteries, where strain (Δd/d0) is a measure of circumferential deformation. Means ± SE for 16 vessels relaxed and then excited at 1 of 10 pressures between 10 and 275 mmHg. Data show curvilinear pressure‐strain relationship of relaxed vessel and more linear curve of contracted vessel. Horizontal distances between relaxed and contracted data points (e.g., ΔPT) represent isometric contractions and reflect unimodal length‐active stress curve of vascular muscle. Vertical distances (e.g., Δd) represent isobaric contractions. Both isometrically and isobarically contracted vessels tend to fall along a single pressure‐strain curve, indicating equivalence of the 2 modes of contraction.

From Dobrin
Figure 8. Figure 8.

Elastic modulus for a relaxed and a contracted cylindrical segment of dog carotid artery. A: circumferential (θ) elastic modulus plotted as function of θ strain after exciting muscle with NE and after inactivation of muscle with KCN. Activating muscle increased elastic modulus at all but largest strains. B: identical data plotted as function of PT. Paradoxically, activating the muscle decreased wall elastic modulus. Arrows point to vessel strains at 100 mmHg in relaxed and contracted states; activating the muscle caused constriction to smaller strains at each pressure, producing decreased modulus when plotted as function of PT.

From Dobrin and Rovick
Figure 9. Figure 9.

A: pressure‐radius curves for dog carotid artery in relaxed, pretreatment state (Pre), after muscle was excited with NE, and after metabolic poisoning with KCN. Relaxed vessel (Pre, KCN) has markedly biphasic pressure‐diameter curve and stiffens at 75–100 mmHg. Muscularly active vessel has decreased dimensions at low pressures and has static pressure‐radius hysteresis. Pressure‐radius coordinates, however, are equal for relaxed and contracted arteries at 300 mmHg . These distension data were used to compute elastic‐modulus data in Fig. . B: stress‐strain curves computed by Gow from data in A. Strain computed with respect to 2 values: 0.078 cm for contracted artery and 0.115 cm for relaxed artery; slopes are proportional to vessel stiffness. Thus computed, relaxed vessel is stiffer than constricted vessel at all except smallest dimensions. Note that computing strains with 2 separate reference values causes identical radii exhibited by the relaxed and contracted artery at 300 mmHg in A to correspond to markedly different strains (highest data points in B). Therefore apparently equivalent strains do not correspond to comparable real dimensions. C and D: radii (r) in A were plotted as function of strain (ɛ). In C, ɛ was computed with respect to 2 separate reference values using Gow's method . Each • was associated with 2 absolute radii. Also each Δr was associated with larger Δɛ for NE‐constricted vessels than for KCN‐relaxed vessel. In D, ɛ was computed with respect to 1 reference value. Each • and Δɛ was associated with 1 r and 1 Δr for both NE‐constricted and KCN‐relaxed vessels.

Figure 10. Figure 10.

Free‐body diagram of cylindrical segment of blood vessel at equilibrium illustrating logitudinal forces. , longitudinal traction force; re and ri, external and internal radii, respectively; σz, longitudinal stress.

Figure 11. Figure 11.

Longitudinal stress (σz) in relaxed cylindrical segment of dog carotid artery plotted as function of circumferential strain. Zero strain indicates vessel circumference of relaxed, excised, totally unloaded vessel. Data show how presence of traction maintains vessel at relatively constant length and σz; σz is the sum of the stress due to traction ( ) and that due to pressure ( ). Interaction between these components results in almost constant net σz up to large circumferential strains and high pressures. Constancy of longitudinal force tends to keep vessel length constant.

Adapted from Dobrin and Doyle , by permission of the American Heart Association, Inc
Figure 12. Figure 12.

Longitudinal extension ratios (λ) for 16 dog carotid arteries (means ± SE). Lengths between identifiable branches were measured in situ immediately after death with neck flexed or extended to 4 positions. Extension ratios were computed by dividing length in situ at each neck position by length of excised, retracted, unloaded vessel.

Figure 13. Figure 13.

Histologic sections of dog carotid artery fixed while loaded uniaxially in radial (r) direction with stresses equivalent to 0, 50, 100, and 150 mmHg. Elastin fixes poorly. However, elastic lamellae are held by fixation of adjacent soft tissues, preventing retraction of lamellae into corrugated configuration. Because load is applied uniaxially it is equal at each point through the wall thickness. To analyze distribution of tissue stiffness, media was divided conceptually into 3rds and lamellae in each 3rd were counted (numbers right of specimens). Although lamellae are distributed nonuniformly across wall thickness, number of lamellae in each 3rd remains approximately constant during loading. Therefore radial elastic modulus is essentially uniform across thickness of media. If it were not, more compressible regions of wall would appear to gain lamellae, while other less compressible regions would appear to lose a commensurate number of lamellae.

Figure 14. Figure 14.

Poisson's ratios in an elastic body representing arterial wall. A: body subjected to uniaxial load in longitudinal (z) direction. This produces incremental strain in the z direction (Δɛz) and causes a narrowing strain in the circumferential (Δɛθ) and the radial directions (Δɛr). B: same elastic body subjected to uniaxial load in the θ direction. This produces incremental strain in the θ direction (Δɛθ) and narrowing strains in the z (Δɛz) and r directions (Δɛr). These strains are used to compute Poisson's ratios (Eqs. ).

From Dobrin
Figure 15. Figure 15.

Data from dog thoracic aorta in situ that illustrate static anisotropy. Eθ, Ez, and Er are moduli in these directions; λθ and λz are extension ratios in θ and z directions. Top panels, means ± SE for longitudinal extension ratios (λz; left to right): 1.45 ± 0.04, 1.56 ± 0.02, and 1.51 ± 0.02. Bottom panels, means ± SE for λθ (left to right): 1.46 ± 0.02, 1.58 ± 0.02, and 1.48 ± 0.02. Eθ, Ez, and Er are not equal.

From Patel et al. , by permission of the American Heart Association, Inc
Figure 16. Figure 16.

Incremental viscoelastic moduli vs. frequency. E′θ, E′z, and E′r are storage, or dynamic elastic moduli, in these directions; E″θ, E″z, and E″r are corresponding loss, or viscous moduli. Vertical bars to right are average SE for each curve; symbols identify appropriate curves.

From Patel et al. , by permission of the American Heart Association, Inc
Figure 17. Figure 17.

Experimental evaluation of exponential and polynomial expressions of strain‐energy density. A and B: comparison of stress‐strain relationships from exponential strain‐energy function given by Eq. and stress expressions given by Eqs. and . Symbols defined in upper left corners. A: circumferential (θ) stress‐strain data. B: longitudinal (z) stress‐strain data. C and D: comparison of stress‐strain relationships from polynomial strain‐energy function given by Eq. and stress expressions given by Eqs. and . C: z stress‐strain data. D: θ stress‐strain data. Both exponential and polynomial expressions agree well with experimental data. Line V is a single value of strain, whereas line H is a single value of stress. Line V does not apply to all vessels, but line H does. This argues for referencing data to a common stress, rather than to a common strain.

From Fung et al.


Figure 1.

Diagram of arterial segment illustrating circumferential (θ), longitudinal (z), and radial (r) directions. Strains and stresses in θ and z directions are tensile because tissue is stretched in these directions with pressurization. Strains and stresses in z direction also are tensile because vessels are elongated at in situ length. Strains and stresses in r direction are compressive because wall becomes thinner with pressurization.

From Dobrin


Figure 2.

A: simultaneous pressure (P) and diameter (D) recordings of right common carotid artery of 68‐yr‐old male patient during operation. Catheter‐tip manometer inserted through side branch into artery recorded P; a noncontact photoelectric gauge with 2 photocells measured D. Recordings illustrate close correspondence between changes in P and D. B: 3 P‐D loops from 64‐yr‐old male patient during operation. Upper limbs correspond to rising phases of arterial pressure cycle. Lower limbs correspond to falling phases. Note dicrotic notch in lower limb. As pulse pressure increased from 30 mmHg (left) to 99 mmHg (right), width of hysteresis loop increased. As mean pressure and pulse pressure increased, curvilinear character of P‐D curve also became evident.

From Busse et al.


Figure 3.

Size and composition of components of vascular tree. End., endothelium; Ela., elastin; Mus., smooth muscle; Fib., fibrous connective tissue—i.e., collagen.

From Burton


Figure 4.

Free‐body diagram of cylindrical segment of blood vessel at equilibrium illustrating circumferential forces. PT, transmural pressure; σθ, circumferential stress; l, vessel length; h, wall thickness; di, internal diameter.



Figure 5.

Distribution of stresses (σ) across artery wall in circumferential (σθ), longitudinal (σz), and radial (σr) directions. Data computed assuming a homogeneous artery wall. Stresses are greatest at lumen and decline curvilinearly across wall thickness; θ and z stresses are tensile and remain positive at all points across wall; σr is compressive and plotted with a negative sign. Unlike σθ and σz, σr vanishes at outer edge of wall. At lumen σr, is equal in magnitude to transmural pressure; σθ and σz are 10–20 times larger in magnitude. Data are for transmural pressure of 150 cmH2O in relaxed vessel, but proportional values have been reported for both contracted and relaxed vessels over a wide range of pressures .

From Vaishnav et al. , by permission of the American Heart Association, Inc


Figure 6.

Stress‐strain relations of dog carotid artery after exciting vascular muscle with supramaximal doses of norepinephrine (NE) and after inactivating vascular muscle with supramaximal doses of potassium cyanide (KCN). Difference between NE and KCN curves gives length‐active stress relationship for vascular muscle. Behavior after treatment with KCN gives stress‐strain relationship for connective tissue. Strain (Δr/r0) is the fractional increase in circumferential length, a measure of circumferential deformation.

From Dobrin and Rovick


Figure 7.

Isometric and isobaric contraction of vascular smooth muscle. A: polygraph record of artery 1st undergoing isometric contraction [pressure (PT) was elevated just enough to maintain vessel diameter constant]. Maintaining isometric contraction required 150‐mmHg increase in PT, which then was reduced to preexcitation levels to permit isobaric contraction. This caused 25% reduction in diameter {Δd). B: summary of pressure‐strain data for 160 arteries, where strain (Δd/d0) is a measure of circumferential deformation. Means ± SE for 16 vessels relaxed and then excited at 1 of 10 pressures between 10 and 275 mmHg. Data show curvilinear pressure‐strain relationship of relaxed vessel and more linear curve of contracted vessel. Horizontal distances between relaxed and contracted data points (e.g., ΔPT) represent isometric contractions and reflect unimodal length‐active stress curve of vascular muscle. Vertical distances (e.g., Δd) represent isobaric contractions. Both isometrically and isobarically contracted vessels tend to fall along a single pressure‐strain curve, indicating equivalence of the 2 modes of contraction.

From Dobrin


Figure 8.

Elastic modulus for a relaxed and a contracted cylindrical segment of dog carotid artery. A: circumferential (θ) elastic modulus plotted as function of θ strain after exciting muscle with NE and after inactivation of muscle with KCN. Activating muscle increased elastic modulus at all but largest strains. B: identical data plotted as function of PT. Paradoxically, activating the muscle decreased wall elastic modulus. Arrows point to vessel strains at 100 mmHg in relaxed and contracted states; activating the muscle caused constriction to smaller strains at each pressure, producing decreased modulus when plotted as function of PT.

From Dobrin and Rovick


Figure 9.

A: pressure‐radius curves for dog carotid artery in relaxed, pretreatment state (Pre), after muscle was excited with NE, and after metabolic poisoning with KCN. Relaxed vessel (Pre, KCN) has markedly biphasic pressure‐diameter curve and stiffens at 75–100 mmHg. Muscularly active vessel has decreased dimensions at low pressures and has static pressure‐radius hysteresis. Pressure‐radius coordinates, however, are equal for relaxed and contracted arteries at 300 mmHg . These distension data were used to compute elastic‐modulus data in Fig. . B: stress‐strain curves computed by Gow from data in A. Strain computed with respect to 2 values: 0.078 cm for contracted artery and 0.115 cm for relaxed artery; slopes are proportional to vessel stiffness. Thus computed, relaxed vessel is stiffer than constricted vessel at all except smallest dimensions. Note that computing strains with 2 separate reference values causes identical radii exhibited by the relaxed and contracted artery at 300 mmHg in A to correspond to markedly different strains (highest data points in B). Therefore apparently equivalent strains do not correspond to comparable real dimensions. C and D: radii (r) in A were plotted as function of strain (ɛ). In C, ɛ was computed with respect to 2 separate reference values using Gow's method . Each • was associated with 2 absolute radii. Also each Δr was associated with larger Δɛ for NE‐constricted vessels than for KCN‐relaxed vessel. In D, ɛ was computed with respect to 1 reference value. Each • and Δɛ was associated with 1 r and 1 Δr for both NE‐constricted and KCN‐relaxed vessels.



Figure 10.

Free‐body diagram of cylindrical segment of blood vessel at equilibrium illustrating logitudinal forces. , longitudinal traction force; re and ri, external and internal radii, respectively; σz, longitudinal stress.



Figure 11.

Longitudinal stress (σz) in relaxed cylindrical segment of dog carotid artery plotted as function of circumferential strain. Zero strain indicates vessel circumference of relaxed, excised, totally unloaded vessel. Data show how presence of traction maintains vessel at relatively constant length and σz; σz is the sum of the stress due to traction ( ) and that due to pressure ( ). Interaction between these components results in almost constant net σz up to large circumferential strains and high pressures. Constancy of longitudinal force tends to keep vessel length constant.

Adapted from Dobrin and Doyle , by permission of the American Heart Association, Inc


Figure 12.

Longitudinal extension ratios (λ) for 16 dog carotid arteries (means ± SE). Lengths between identifiable branches were measured in situ immediately after death with neck flexed or extended to 4 positions. Extension ratios were computed by dividing length in situ at each neck position by length of excised, retracted, unloaded vessel.



Figure 13.

Histologic sections of dog carotid artery fixed while loaded uniaxially in radial (r) direction with stresses equivalent to 0, 50, 100, and 150 mmHg. Elastin fixes poorly. However, elastic lamellae are held by fixation of adjacent soft tissues, preventing retraction of lamellae into corrugated configuration. Because load is applied uniaxially it is equal at each point through the wall thickness. To analyze distribution of tissue stiffness, media was divided conceptually into 3rds and lamellae in each 3rd were counted (numbers right of specimens). Although lamellae are distributed nonuniformly across wall thickness, number of lamellae in each 3rd remains approximately constant during loading. Therefore radial elastic modulus is essentially uniform across thickness of media. If it were not, more compressible regions of wall would appear to gain lamellae, while other less compressible regions would appear to lose a commensurate number of lamellae.



Figure 14.

Poisson's ratios in an elastic body representing arterial wall. A: body subjected to uniaxial load in longitudinal (z) direction. This produces incremental strain in the z direction (Δɛz) and causes a narrowing strain in the circumferential (Δɛθ) and the radial directions (Δɛr). B: same elastic body subjected to uniaxial load in the θ direction. This produces incremental strain in the θ direction (Δɛθ) and narrowing strains in the z (Δɛz) and r directions (Δɛr). These strains are used to compute Poisson's ratios (Eqs. ).

From Dobrin


Figure 15.

Data from dog thoracic aorta in situ that illustrate static anisotropy. Eθ, Ez, and Er are moduli in these directions; λθ and λz are extension ratios in θ and z directions. Top panels, means ± SE for longitudinal extension ratios (λz; left to right): 1.45 ± 0.04, 1.56 ± 0.02, and 1.51 ± 0.02. Bottom panels, means ± SE for λθ (left to right): 1.46 ± 0.02, 1.58 ± 0.02, and 1.48 ± 0.02. Eθ, Ez, and Er are not equal.

From Patel et al. , by permission of the American Heart Association, Inc


Figure 16.

Incremental viscoelastic moduli vs. frequency. E′θ, E′z, and E′r are storage, or dynamic elastic moduli, in these directions; E″θ, E″z, and E″r are corresponding loss, or viscous moduli. Vertical bars to right are average SE for each curve; symbols identify appropriate curves.

From Patel et al. , by permission of the American Heart Association, Inc


Figure 17.

Experimental evaluation of exponential and polynomial expressions of strain‐energy density. A and B: comparison of stress‐strain relationships from exponential strain‐energy function given by Eq. and stress expressions given by Eqs. and . Symbols defined in upper left corners. A: circumferential (θ) stress‐strain data. B: longitudinal (z) stress‐strain data. C and D: comparison of stress‐strain relationships from polynomial strain‐energy function given by Eq. and stress expressions given by Eqs. and . C: z stress‐strain data. D: θ stress‐strain data. Both exponential and polynomial expressions agree well with experimental data. Line V is a single value of strain, whereas line H is a single value of stress. Line V does not apply to all vessels, but line H does. This argues for referencing data to a common stress, rather than to a common strain.

From Fung et al.
References
 1. Aars, H. Static load‐length characteristics of aortic strips from hypertensive rabbits. Acta Physiol. Scand. 73: 101–110, 1968.
 2. Aars, H. Relationship between aortic diameter and aortic baroreceptor activity in normal and hypertensive rabbits. Acta Physiol. Scand. 75: 406–414, 1969.
 3. Alexander, R. S. The influence of constrictor drugs on the distensibility of the splanchnic venous system analyzed on the basis of an aortic model. Circ. Res. 2: 140–147, 1954.
 4. Alexander, R. S. Role of calcium in the plasticity of venous smooth muscle. Am. J. Physiol. 213: 287–294, 1967.
 5. Alexander, R. S. Series elasticity of urinary bladder smooth muscle. Am. J. Physiol. 231: 1337–1342, 1976.
 6. Alexander, R. S. Critical closure reexamined. Circ. Res. 40: 531–535, 1977.
 7. Angell‐James, J. E. The effects of changes of extramural, intrathoracic pressure on aortic arch baroreceptors. J. Physiol. London 24: 89–103, 1971.
 8. Angell‐James, J. E. Arterial baroreceptor activity in rabbits with experimental atherosclerosis. Circ. Res. 34: 27–39, 1974.
 9. Anliker, M., W. E. Mortiz, and E. Ogden. Transmission characteristics of axial waves in blood vessels. J. Biomech. 1: 235–246, 1968.
 10. Apter, J. T. Correlation of visco‐elastic properties with microscopic structure of large arteries. IV. Thermal responses of collagen, elastin, smooth muscle, and intact arteries. Circ. Res. 21: 901–918, 1967.
 11. Apter, J. T., E. Marquez, and M. Janas. Dynamic visco‐elastic anisotropy of canine aorta correlated with wall composition. J. Assoc. Adv. Med. Instrum. 4: 15–21, 1970.
 12. Arndt, J. O., and G. Kober. Pressure diameter relationship of the intact femoral artery in conscious man. Pfluegers Arch. 318: 130–146, 1970.
 13. Attinger, F. M. L. Two‐dimensional in vitro studies of femoral arterial walls of the dog. Circ. Res. 22: 829–840, 1968.
 14. Ayer, J. P., G. M. Hass, and D. E. Philpott. Aortic elastic tissue: isolation with use of formic acid and discussion of some of its properties. AMA Arch. Pathol. 65: 519–544, 1958.
 15. Azuma, T., and M. Hasegawa. A rheological approach to the architecture of arterial walls. Jpn. J. Physiol. 21: 27–47, 1971.
 16. Azuma, T., T. Ohhashi, and M. Sakaguchi. Vibration‐induced hyperresponsiveness of arterial smooth muscle to noradrenaline with special reference to Raynaud's phenomenon in vibration disease. Cardiovasc. Res. 12: 758–764, 1978.
 17. Azuma, T., and S. Oka. Mechanical equilibrium of blood vessel walls. Am. J. Physiol. 221: 1310–1318, 1971.
 18. Bader, H. The anatomy and physiology of the vascular wall. In: Handbook of Physiology. Circulation, edited by W. F. Hamilton. Washington, DC: Am. Physiol. Soc., 1963, sect. 2, vol. II., chapt. 26, p. 865–889.
 19. Bader, H. Dependence of wall stress in the human thoracic aorta on age and pressure. Circ. Res. 20: 354–361, 1967.
 20. Bagshaw, R. J., and F. M. L. Attinger. Two directional delayed compliance in the canine abdominal aorta. Experientia 28: 803–804, 1972.
 21. Bagshaw, R. J., and F. M. L. Attinger. Longitudinal stress relaxation in the canine aorta. Experientia 30: 1046–1047, 1974.
 22. Bagshaw, R. J., and G. M. Fischer. Morphology of the carotid sinus in the dog. J. Appl. Physiol. 31: 198–202, 1971.
 23. Bagshaw, R. J., and L. H. Peterson. Sympathetic control of the mechanical properties of the canine carotid sinus. Am. J. Physiol. 222: 1462–1468, 1972.
 24. Bailey, J. M. Elasticity and tensile strength of normal and atherosclerotic rabbit aorta. J. Atheroscler. Res. 5: 112–119, 1965.
 25. Balakrishna, R., N. Chakravarti, and S. H. Zaidi. Elasticity of isolated aorta in cholesterol fed rabbits. Indian J. Med. Res. 49: 400–407, 1961.
 26. Band, W., W. J. A. Goedhard, and A. A. Knoop. Effects of aging on dynamic viscoelastic properties of the rat's thoracic aorta. Pfluegers Arch. 331: 357–364, 1972.
 27. Band, W., W. J. A. Goedhard, and A. A. Knoop. Comparison of effects of high cholesterol intake on viscoelastic properties of the thoracic aorta in rats and rabbits. Atherosclerosis 18: 163–172, 1973.
 28. Bandick, N. R., and H. V. Sparks. Contractile response of vascular smooth muscle of renal hypertensive rats. Am. J. Physiol. 219: 340–344, 1970.
 29. Bandick, N. R., and H. V. Sparks. Viscoelastic properties of the aorta of hypertensive rats. Proc. Soc. Exp. Biol. Med. 134: 56–60, 1971.
 30. Banga, I., and J. Balo. Elasticity of the vascular wall. I. The elastic tensibility of the human carotid as a function of age and arteriosclerosis. Acta Physiol. Acad. Sci. Hung. 20–21: 237–247, 1961.
 31. Bauer, R. D., and T. Pasch. The quasistatic and dynamic circumferential elastic modulus of the rat tail artery studied at various wall stresses and tones of the vascular smooth muscle. Pfluegers Arch. 330: 335–346, 1971.
 32. Benjamin, H. B., and A. B. Becker. Etiology incidence of thoracic and abdominal aortic aneurysms. Surg. Gynecol. Obstet. 125: 1307–1310, 1967.
 33. Berecek, K. H., and D. F. Bohr. Structural and functional changes in vascular resistance and reactivity in the deoxycorticosterone acetate (DOCA)‐hypertensive pig. Circ. Res. 40, Suppl. 1: 146–151, 1977.
 34. Bergel, D. H. The static elastic properties of the arterial wall. J. Physiol. London 156: 445–457, 1961.
 35. Bergel, D. H. The dynamic elastic properties of the arterial wall. J. Physiol. London 156: 458–469, 1961.
 36. Bergel, D. H., D. E. Brooks, A. J. MacDermott, J. L. Robinson, and P. Sleight. The relation between carotid sinus dimension, nerve activity and pressure in the anesthetized greyhound. J. Physiol. London 263: 156–157, 1976.
 37. Bevan, R. D., E. van Marthens, and J. A. Bevan. Hyperplasia of vascular smooth muscle in experimental hypertension in the rabbit. Circ. Res. 38, Suppl. 2: 58–62, 1976.
 38. Boughner, D. R., and M. R. Roach. Effect of low frequency vibration on the arterial wall. Circ. Res. 29: 136–144, 1971.
 39. Brown, A. M., W. R. Saum, and F. H. Tuley. A comparison of aortic baroreceptor discharge in normotensive and spontaneously hypertensive rats. Circ. Res. 39: 488–496, 1976.
 40. Browse, N. L., A. E. Young, and M. L. Thomas. The effect of bending on canine and human arterial walls and on blood flow. Circ. Res. 45: 41–48, 1979.
 41. Buñag, R. D., and K. Takeda. Sympathetic hyperresponsiveness to hypothalamic stimulation in young hypertensive rats. Am. J. Physiol. 237 (Regulatory Integrative Comp. Physiol. 6): R39–R44, 1979.
 42. Burton, A. C. On the physical equilibrium of small blood vessels. Am. J. Physiol. 164: 319–329, 1951.
 43. Burton, A. C. Relation of structure to function of the tissues of the wall of blood vessels. Physiol. Rev. 34: 619–642, 1954.
 44. Busse, R., R. D. Bauer, T. Sattler, and A. Schabert. Dependence of elastic and viscous properties of elastic arteries on circumferential wall stress at two different smooth muscle tones. Pfluegers Arch. In press.
 45. Busse, R., R. D. Bauer, A. Schabert, Y. Summa, P. Bumm, and E. Wetterer. The mechanical properties of exposed human common carotid arteries in vivo. Basic Res. Cardiol. 74: 545–554, 1979.
 46. Busse, R., R. D. Bauer, Y. Summa, H. Korner, and T. Pasch. Comparison of the visco‐elastic properties of the tail artery in spontaneously hypertensive and normotensive rats. Pfluegers Arch. 364: 175–181, 1976.
 47. Busuttil, R. W., A. M. Abou‐Zamzam, and H. I. Machleder. Collagenase activity of the human aortic: a comparison of patients with and without abdominal aortic aneurysms. Arch. Surg. Chicago 115: 1373–1378, 1980.
 48. Busu, R. W., R. Heinrich, and A. Flesher. Elastase activity: the role of elastase in aortic aneurysm formation. J. Surg. Res. In press.
 49. Butler, T. M., M. J. Siegman, and R. E. Davies. Rigor and resistance to stretch in vertebrate smooth muscle. Am. J. Physiol. 231: 1509–1514, 1976.
 50. Carew, T. E., and D. J. Patel. Effect of tensile and shear stress on intimal permeability of the left coronary artery in dogs. Atherosclerosis 18: 179–189, 1973.
 51. Carew, T. E., R. N. Vaishnav, and D. J. Patel. Compressibility of the arterial wall. Circ. Res. 23: 61–68, 1968.
 52. Caro, C. G., and R. M. Nerem. Transport of 14C‐4‐cholesterol between serum and wall in the perfused dog common carotid artery. Circ. Res. 32: 187–205, 1975.
 53. Carton, R. W., J. Dainauskas, and J. W. Clark. Elastic properties of single elastic fibers. J. Appl. Physiol. 17: 547–551, 1962.
 54. Clark, J. M., and S. Glagov. Structural integration of the arterial wall. I. Relationships and attachments of medial smooth muscle cells in normally distended and hyperdistended aortas. Lab. Invest. 40: 587–607, 1979.
 55. Cohen, J., S. Litwin, A. Aaron, and S. Fine. The rupture force and tensile strength of canine aortic tissue. J. Surg. Res. 13: 321–333, 1972.
 56. Cox, R. H. A model for the dynamic mechanical properties of arteries. J. Biomech. 5: 135–152, 1972.
 57. Cox, R. H. Anisotropic properties of the canine carotid artery in vitro. J. Biomech. 8: 293–300, 1975.
 58. Cox, R. H. Mechanics of canine iliac artery smooth muscle in vitro. Am. J. Physiol. 230: 462–470, 1976.
 59. Cox, R. H. Determination of series elasticity in arterial smooth muscle. Am. J. Physiol. 233 (Heart Circ. Physiol. 2): H248–H255, 1977.
 60. Cox, R. H. Influence of muscle length on series elasticity in arterial smooth muscle. Am. J. Physiol. 234 (Cell Physiol. 3): C146–C154, 1978.
 61. Cox, R. H. Passive mechanics and connective tissue composition of canine arteries. Am. J. Physiol. 234 (Heart Circ. Physiol. 3): H533–H541, 1978.
 62. Cox, R. H. Regional variation of series elasticity in canine arterial smooth muscles. Am. J. Physiol. 234 (Heart Circ. Physiol. 3): H542–H551, 1978.
 63. Cox, R. H. Comparison of arterial wall mechanics in normotensive and spontaneously hypertensive rats. Am. J. Physiol. 237 (Heart Circ. Physiol. 6): H159–H167, 1979.
 64. Cox, R. H., and D. K. Detweiler. Arterial wall properties and dietary atherosclerosis in the racing greyhound. Am. J. Physiol. 236 (Heart Circ. Physiol. 5): H790–H797, 1979.
 65. Cox, R. H., A. W. Jones, and M. L. Swain. Mechanics and electrolyte composition of arterial smooth muscle in developing dogs. Am. J. Physiol. 231: 77–83, 1976.
 66. Csapo, A., and M. Goodall. Excitability, length‐tension relation and kinetics of uterine muscle contraction in relation to hormonal status. J. Physiol. London 126: 384–395, 1954.
 67. Davis, D. L., and C. H. Baker. Arterial segment constriction under constant‐pressure and constant‐inflow perfusion. Am. J. Physiol. 227: 1149–1157, 1974.
 68. Dillon, P. F., M. O. Aksoy, S. P. Driska, and R. A. Murphy. Myosin phosphorylation and the cross‐bridge cycle in arterial smooth muscle. Science 211: 495–497, 1981.
 69. Dobrin, P. B. Isometric and isobaric contraction of carotid arterial smooth muscle. Am. J. Physiol. 225: 659–663, 1973.
 70. Dobrin, P. B. Influence of initial length on length‐tension relationship of vascular smooth muscle. Am. J. Physiol. 225: 664–670, 1973.
 71. Dobrin, P. B. Vascular muscle series elastic element stiffness during isometric contraction. Circ. Res. 34: 242–250, 1974.
 72. Dobrin, P. B. Mechanical properties of arteries. Physiol. Rev. 58: 397–460, 1978.
 73. Dobrin, P. B. Balloon embolectomy catheters in small arteries. I. Lateral wall pressures and shear forces. Surgery 90: 177–185, 1981.
 74. Dobrin, P. B. Cited in K. Johansen. Aneurysms. Sci. Am. 247: 110–125, 1982.
 75. Dobrin, P. B., and T. R. Canfield. Series elastic and contractile elements in vascular smooth muscle. Circ. Res. 33: 454–464, 1973.
 76. Dobrin, P., and T. R. Canfield. Identification of smooth muscle series elastic component in intact carotid artery. Am. J. Physiol. 232 (Heart Circ. Physiol. 1): H122–H130, 1977.
 77. Dobrin, P., T. R. Canfield, J. Moran, H. Sullivan, and R. Pifarre. Coronary artery bypass: the physiological basis for differences in flow with internal mammary artery and saphenous vein grafts. J. Thorac. Cardiovasc. Surg. 74: 445–454, 1977.
 78. Dobrin, P., T. R. Canfield, and S. Sinha. Development of longitudinal retraction of carotid arteries in neonatal dogs. Experientia 31: 1295–1296, 1975.
 79. Dobrin, P. B., and J. M. Doyle. Vascular smooth muscle and the anisotropy of dog carotid artery. Circ. Res. 27: 105–119, 1970.
 80. Dobrin, P. B., and A. A. Rovick. Influence of vascular smooth muscle on contractile mechanics and elasticity of arteries. Am. J. Physiol. 217: 1644–1652, 1969.
 81. Doyle, J. M., and P. B. Dobrin. Finite deformation analysis of the relaxed and contracted dog carotid artery. Microvasc. Res. 3: 400–415, 1971.
 82. Doyle, J. M., and P. B. Dobrin. Stress gradients in the walls of large arteries. J. Biomech. 6: 631–639, 1973.
 83. Driska, S. P., D. N. Damon, and R. A. Murphy. Estimates of cellular mechanics in an arterial smooth muscle. Biophys. J. 24: 525–540, 1978.
 84. DuJardin, J. P., L. T. Paul, and H. P. Pieper. Effect of acute volume loading on aortic smooth muscle activity in intact dogs. Am. J. Physiol. 238 (Heart Circ. Physiol. 7): H379–H383, 1980.
 85. Duling, B. R., R. W. Gore, R. G. Dacey, Jr., and D. N. Damon. Methods for isolation, cannulation, and in vitro study of single microvessels. Am. J. Physiol. 241 (Heart Circ. Physiol. 10): H108–H116, 1981.
 86. Duncan, L. E., Jr., K. Buck, and A. Lynch. The effect of pressure and stretching on the passage of labeled albumin into canine aortic wall. Atherosclerosis 5: 69–79, 1965.
 87. Farrar, D. J., H. D. Green, W. D. Wagner, and M. G. Bond. Reduction in pulse wave velocity and improvement of aortic distensibility accompanying regression of atherosclerosis in the rhesus monkey. Circ. Res. 47: 425–432, 1980.
 88. Feigl, E. O., L. H. Peterson, and A. W. Jones. Mechanical and chemical properties of arteries in experimental hypertension. J. Clin. Invest. 42: 1640–1647, 1963.
 89. Fenn, W. O. Changes in length of blood vessels on inflation. In: Tissue Elasticity, edited by J. W. Remington. Washington, DC: Am. Physiol. Soc., 1957, p. 154–167.
 90. Fischer, G. M., and J. G. Llaurado. Collagen and elastin content in canine arteries selected from functionally different vascular beds. Circ. Res. 19: 394–399, 1966.
 91. Fischer, G. M., and J. G. Llaurado. Connective tissue composition of canine arteries: effects of renal hypertension. Arch. Pathol. 84: 95–98, 1967.
 92. Fischer, G. M., M. L. Swain, and K. Cherian. Increased vascular collagen and elastin synthesis in experimental atherosclerosis in the rabbit. Variation in synthesis among major vessels. Atherosclerosis 35: 11–20, 1980.
 93. Fisher, B. A., and R. M. Bagby. Reorientation of myofilaments during contraction of a vertebrate smooth muscle. Am. J. Physiol. 232 (Cell Physiol. 1): C5–C14, 1977.
 94. Flaherty, J. T., J. E. Pierce, V. J. Ferrans, D. S. Patel, W. K. Tucker, and D. L. Fry. Endothelial nuclear patterns in the canine arterial tree with particular reference to hemodynamic events. Circ. Res. 30: 23–33, 1972.
 95. Folkow, B., and R. Sivertsson. Adaptive changes in “reactivity” and wall/lumen ratio in cat blood vessels exposed to prolonged transmural pressure difference. Life Sci. 7: 1283–1289, 1968.
 96. Foreman, J. E. K., and K. J. Hutchison. Arterial wall vibration distal to stenoses in isolated arteries of dog and man. Circ. Res. 26: 583–590, 1970.
 97. Fry, D. L. Acute vascular endothelial changes associated with increased blood velocity gradients. Circ. Res. 22: 165–197, 1968.
 98. Fry, D. L. Hemodynamic forces in atherogenesis. In: Cerebrovascular Diseases, edited by P. Scheinberg. New York: Raven, 1976, p. 77–95.
 99. Fry, D. L., R. W. Mahley, and S. Y. Oh. Effect of arterial stretch on transmural albumin and Evans blue dye transport. Am. J. Physiol. 240 (Heart Circ. Physiol. 9): H645–H649, 1981.
 100. Fung, Y. C. B. Elasticity of soft tissues in simple elongation. Am. J. Physiol. 213: 1532–1544, 1967.
 101. Fung, Y. C. B., K. Fronek, and P. Patitucci. Pseudoelasticity of arteries and the choice of its mathematical expression. Am. J. Physiol. 237 (Heart Circ. Physiol. 6): H620–H631, 1979.
 102. Geiringer, E. Intimal vascularization and atheromatosis. J. Pathol. Bacteriol. 63: 201–211, 1951.
 103. Gero, J., and M. Gerová. Sympathetic regulation of arterial distensibility. Physiol. Biochemoslov. 18: 480–481, 1969.
 104. Gerová, M., and J. Gero. Reflex regulation of smooth muscle tone of conduit vessel. Angiologica 4: 348–358, 1967.
 105. Gerová, M., and J. Gero. Range of sympathetic control of the dog femoral artery. Circ. Res. 24: 349–359, 1969.
 106. Goedhard, W. J. A., and A. A. Knoop. A model of the arterial wall. J. Biomech. 6: 281–288, 1973.
 107. Gore, R. W. Wall stress: a determinant of regional differences in response of frog microvessels to norepinephrine. Am. J. Physiol. 222: 82–91, 1972.
 108. Goto, M., and Y. Kimoto. Hysteresis and stress‐relaxation of the blood vessels studied by a Universal Tensile Testing Instrument. Jpn. J. Physiol. 16: 169–184, 1966.
 109. Gow, B. S. Viscoelastic properties of conduit arteries. Circ. Res. 25, Suppl. 2: 113–122, 1970.
 110. Gow, B. S. Circulatory correlates: vascular impedance, resistance, and capacity. In: Handbook of Physiology. The Cardiovascular System. Vascular Smooth Muscle, edited by D. F. Bohr, A. P. Somlyo, and H. V. Sparks, Jr. Bethesda, MD: Am. Physiol. Soc., 1980, sect. 2, vol. II, chapt. 14, p. 353–408.
 111. Gow, B. S., and C. D. Hadfield. The elasticity of canine and human coronary arteries with reference to postmortem changes. Circ. Res. 45: 588–594, 1979.
 112. Gow, B. S., and M. G. Taylor. Measurement of viscoelastic properties of arteries in the living dog. Circ. Res. 23: 111–122, 1968.
 113. Greenberg, S., and D. F. Bohr. Venous smooth muscle in hypertension. Enhanced contractility of portal veins from spontaneously hypertensive rats. Circ. Res. 36, Suppl. 1: 208–215, 1975.
 114. Greenberg, S., K. Gaines, and D. Sweatt. Evidence for circulating factors as a cause of venous hypertrophy in spontaneously hypertensive rats. Am. J. Physiol. 241 (Heart Circ. Physiol. 10): H421–H430, 1981.
 115. Greene, M. A., R. Friedlander, A. J. Boltax, C. G. Hadjigeorge, and G. A. Lustig. Distensibility of arteries in human hypertension. Proc. Soc. Exp. Biol. Med. 121: 580–585, 1966.
 116. Greenwald, S. E., and C. L. Berry. Static mechanical properties and chemical composition of the aorta of spontaneoiusly hypertensive rats: a comparison of the effects of induced hypertension. Cardiovasc. Res. 12: 364–372, 1978.
 117. Halloway, E. T. and D. F. Bohr. Reactivity of vascular smooth muscle in hypertensive rats. Circ. Res. 33: 678–685, 1973.
 118. Halpern, W., S. A. Mongeon, and D. T. Root. Stress, tension and myogenic aspects of small isolated extraparenchymal rat arteries. In: Smooth Muscle Contraction, edited by N. L. Stephens. New York: Dekker, in press.
 119. Hansen, T. R., G. D. Abrams, and D. F. Bohr. Role of pressure in structural and functional changes in arteries of hypertensive rats. Circ. Res. 34, Suppl. 1: 101–107, 1974.
 120. Hardung, V. Über eine Methode zur Messung der dynamischen Elastizität and Viskosität kautschukähnlicher Körper, insbesondere von Blutgefässen und anderen elastischen Gewebteilen. Helv. Physiol. Pharmacol. Acta 10: 482–498, 1952.
 121. Hardung, V. Vergleicheude Messungen der dynamischen Elastizität and Viskosität von Blutgefässen, Kautschauk und synthetischen Elastomeren. Helv. Physiol. Pharmacol. Acta 11: 194–211, 1953.
 122. Hardung, V. Die Bedeutung der Anisotropie und Inhomogenität bei der Bestimmung der Elastizität der Blutgefässe II. Angiologica 1: 185–196, 1964.
 123. Harkness, M. L. R., R. D. Harkness, and D. A. McDonald. The collagen and elastin content of the arterial wall in the dog. Proc. R. Soc. London Ser. B 146: 541–551, 1957.
 124. Hauss, W. H., H. Kreuziger, and H. Asteroth. Über die Reizung der Pressorezeptoren im Sinus caroticus beim Hund. Z. Kreislaufforsch. 38: 28–33, 1949.
 125. Heistad, D. D., M. L. Armstrong, and M. L. Marcus. Hyperemia of the aortic wall in atherosclerotic monkeys. Circ. Res. 48: 669–675, 1981.
 126. Heistad, D. D., M. L. Marcus, G. E. Larsen, and M. L. Armstrong. Role of vasa vasorum in nourishment of the aortic wall. Am. J. Physiol. 240 (Heart Circ. Physiol. 9): H781–H787, 1981.
 127. Heistad, D. D., M. L. Marcus, E. Law, M. L. Armstrong, J. C. Ehrhardt, and F. M. Abboud. Regulation of blood flow to the aortic media in dogs. J. Clin. Invest. 62: 133–140, 1978.
 128. Heistad, D. D., M. L. Marcus, and J. B. Martins. Effect of neural stimuli on blood flow through vasa vasorum in dogs. Circ. Res. 45: 615–620, 1979.
 129. Helin, P., and I. B. Lorenzen. Atherosclerosis in rabbit aorta induced by systemic hypoxia. Angiology 20: 1–12, 1969.
 130. Herlihy, J. T. Helically cut vascular strip preparation: geometrical considerations. Am. J. Physiol. 238 (Heart Circ. Physiol. 7): H107–H109, 1980.
 131. Herlihy, J. T., and R. A. Murphy. Length‐tension relationship of smooth muscle of the hog carotid artery. Circ. Res. 33: 275–283, 1973.
 132. Herlihy, J. T., and R. A. Murphy. Force‐velocity and series elastic characteristics of smooth muscle from the hog carotid artery. Circ. Res. 34: 461–466, 1974.
 133. Hermsmeyer, K. Cellular basis for increased sensitivity of vascular smooth muscle in spontaneously hypertensive rats. Circ. Res. 38, Suppl. 2: 53–57, 1976.
 134. Hesse, M. Über die Pathologischen Veranderungen der Arterien der oberen Extremität. Virchows Arch. Pathol. Anat. Physiol. 261: 225–252, 1926.
 135. Hinke, J. A. M., and M. L. Wilson. A study of elastic properties of a 550‐μ artery in vitro. Am. J. Physiol. 203: 1153–1160, 1962.
 136. Hirst, A. F., and I. Gore. Is cystic medial necrosis the cause of dissecting aortic aneurysm? Circulation 53: 915–916, 1976.
 137. Ho, K. J., C. Y. Lin, F. T. Gaylash, A. S. Patel, L. B. Liu, and C. B. Taylor. Aortic compliance. Studies on its relationship to aortic constituents in man. Arch. Pathol. 94: 537–546, 1972.
 138. Ingram, R. H., Jr., J. P. Szidon, and A. P. Fishman. Response of the main pulmonary artery of dogs to neuronally released versus blood‐borne norepinephrine. Circ. Res. 26: 249–262, 1970.
 139. Jaeger, M. Etude de l'élasticité et des tensions de la carotide de vache en comparison avec l'aorte et la coronaire. Helv. Physiol. Pharmacol. Acta 20: 7–24, 1962.
 140. Johnson, P. C. Autoregulating response of cat mesenteric arterioles measured in vivo. Circ. Res. 22: 199–212, 1968.
 141. Jones, A. W. Altered ion transport in vascular smooth muscle from spontaneously hypertensive rats. Circ. Res. 33: 563–572, 1973.
 142. Kagan, H. M., P. E. Milbury, Jr., and D. M. Kramsch. A possible role for elastin ligands in the proteolytic degradation of arterial elastic lamellae in the rabbit. Circ. Res. 44: 95–103, 1979.
 143. Kapal, E. Die elastischen Eigenschaften der Aortenwand sowie des elastischen und kollagenen Bindegewebes bei frequenten zykilschen Beanspruchungen. Z. Biol. Munich 107: 347–404, 1954.
 144. Keatinge, W. R., and C. Torrie. Action of sympathetic nerves on inner and outer muscle of sheep carotid artery, and effect of pressure on nerve distribution. J. Physiol. London 257: 699–712, 1976.
 145. Kezdi, P. Mechanism of the carotid sinus in experimental hypertension. Circ. Res. 11: 145–152, 1962.
 146. Koizumi, K., and A. Sato. Influence of sympathetic innervation on carotid sinus baroreceptor activity. Am. J. Physiol. 216: 321–329, 1969.
 147. Koushanpour, E., and D. M. Kelso. Partition of the carotid sinus baroreceptor response in dogs between the mechanical properties of the wall and the receptor elements. Circ. Res. 31: 831–845, 1972.
 148. Koushanpour, E., and K. J. Kenfield. Partition of carotid sinus baroreceptor response in dogs with chronic renal hypertension. Circ. Res. 48: 267–273, 1981.
 149. Krafka, J., Jr. Comparative study of the histo‐physics of the aorta. Am. J. Physiol. 125: 1–14, 1939.
 150. Lambossy, P. L'anisotropie des arteres. Essai théorique avec application à des resultats d'expèrience. Angiologica 4: 129–146, 1967.
 151. Landgren, S. The baroreceptor activity in the carotid sinus nerve and the distensibility of the sinus wall. Acta Physiol. Scand. 26: 35–56, 1952.
 152. Langner, R. O., J. P. Gilligan, and L. A. Ehrhart. The effect of cholesterol feeding on protein synthesis in different regions of rabbit arterial wall. Exp. Mol. Pathol. 31: 308–317, 1979.
 153. Lawton, R. W. The thermoelastic behavior of isolated aortic strips of the dog. Circ. Res. 2: 344–353, 1954.
 154. Lawton, R. W. Some aspects of research in biological elasticity. Introductory remarks. In: Tissue Elasticity, edited by J. W. Remington. Washington, DC: Am. Physiol. Soc., 1957, p. 1–11.
 155. Learoyd, B. M., and M. G. Taylor. Alterations with age in the viscoelastic properties of human arterial walls. Circ. Res. 18: 278–292, 1966.
 156. Lekhnitskii, S. G. Theory of Elasticity of an Anisotropic Elastic Body. San Francisco, CA: Helden‐Day, 1963.
 157. Leonard, E., and S. J. Sarnoff. Effect of aramine‐induced smooth muscle contraction of length‐tension diagrams of venous strips. Circ. Res. 5: 169–174, 1957.
 158. Leung, D. Y. M., S. Glagov, and M. B. Mathews. Cyclic stretching stimulates synthesis of matrix components by arterial smooth muscle cells in vitro. Science 191: 475–477, 1976.
 159. Ling, S. C., H. B. Atabek, W. G. Letzing, and D. J. Patel. Nonlinear analysis of aortic flow in living dogs. Circ. Res. 33: 198–212, 1973.
 160. Ljung, B., and R. Sivertsson. Vibration‐induced inhibition of vascular smooth muscle contraction. Blood Vessels 12: 38–52, 1975.
 161. Lundholm, L., and E. Mohme‐Lundholm. Lengths at inactivated contractile elements, length‐tension diagram, active state and tone of vascular smooth muscle. Acta Physiol. Scand. 68: 347–359, 1966.
 162. Lutz, R. J., J. N. Cannon, K. B. Bischoff, R. L. Dedrick, R. K. Stiles, and D. L. Fry. Wall shear stress distribution in a model canine artery during steady flow. Circ. Res. 41: 391–399, 1977.
 163. Mangle, A., M. Fahim, and C. van Breemen. Control of vascular contractility by the cardiac pacemaker. Science 215: 1627–1629, 1982.
 164. McCubbin, J. W., J. H. Green, and I. H. Page. Baroreceptor function in chronic renal hypertension. Circ. Res. 4: 205–210, 1956.
 165. McDonald, D. A. Regional pulse‐wave velocity in the arterial tree. J. Appl. Physiol. 24: 73–78, 1968.
 166. Meyers, H. A., and C. R. Honig. Influence of initial resistance on magnitude of response to vasomotor stimuli. Am. J. Physiol. 216: 1429–1436, 1969.
 167. Mulvany, M. J. The damped and undamped series elastic components of a vascular smooth muscle. Biophys. J. 26: 401–414, 1979.
 168. Mulvany, M. J., and W. Halpern. Contractile properties of small arterial resistance vessels in spontaneously hypertensive and normotensive rats. Circ. Res. 41: 19–26, 1977.
 169. Murphy, R. A. Mechanics of vascular smooth muscle. In: Handbook of Physiology. The Cardiovascular System, edited by D. F. Bohr, A. P. Somlyo, and H. V. Sparks, Jr. Bethesda, MD: Am. Physiol. Soc., 1980, sect. 2, vol. II, chapt. 13, p. 325–351.
 170. Newman, D. L., N. L. R. Bowden, and R. G. Gosling. The dynamic and static elastic response of the abdomen aorta of the dog. Cardiovasc. Res. 9: 679–684, 1975.
 171. Newman, D. L., R. G. Gosling, and N. L. R. Bowden. Changes in aortic distensibility and area ratio with the development of atherosclerosis. Atherosclerosis 14: 231–240, 1971.
 172. Nichol, J. T. The effect of cholesterol feeding on the distensibility of the isolated thoracic aorta of the rabbit. Can. J. Biochem. Physiol. 33: 507–516, 1955.
 173. Ohhashi, T., and T. Azuma. Paradoxical relaxation of arterial strips induced by vasoconstrictive agents. Blood Vessels 17: 16–26, 1980.
 174. Ohhashi, T., T. Azuma, and M. Sakaguchi. Active and passive mechanical characteristics of bovine mesenteric lymphatics. Am. J. Physiol. 239 (Heart Circ. Physiol. 8): H88–H95, 1980.
 175. Ooshima, A. Collagen αB chain: increased proportion in human atherosclerosis. Science 213: 666–668, 1981.
 176. Ooshima, A., G. Fuller, G. Cardinale, S. Spector, and S. Udenfriend. Collagen biosynthesis in blood vessels of brain and other tissues of the hypertensive rat. Science 190: 898–900, 1975.
 177. O'Rourke, M. F., J. V. Blazek, C. L. Morreels, Jr., and L. J. Krovetz. Pressure wave transmission along the human aorta. Changes with age and in arterial degenerative disease. Circ. Res. 23: 567–579, 1968.
 178. Pagani, M., I. Mirsky, H. Baig, W. T. Manders, P. Kerkhof, and S. F. Vatner. Effects of age on aortic pressure‐diameter and elastic stiffness‐stress relationships in unanesthetized sheep. Circ. Res. 44: 420–429, 1979.
 179. Pate, J. W., and P. N. Sawyer. Some elastic characteristics of fresh and freeze‐dried aortic grafts. Am. J. Surg. 86: 653–658, 1953.
 180. Patel, D. J. Hemodynamics and Its Role in Disease Processes. Baltimore, MD: University Park, 1980.
 181. Patel, D. J., F. M. Defreitas, J. C. Greenfield, Jr., and D. L. Fry. Relationship of radius to pressure along the aorta in living dogs. J. Appl. Physiol. 18: 1111–1117, 1963.
 182. Patel, D. J., and D. L. Fry. In situ pressure‐radius‐length measurements in ascending aorta of anesthetized dogs. J. Appl. Physiol. 19: 413–416, 1964.
 183. Patel, D. J., and D. L. Fry. Longitudinal tethering of arteries in dogs. Circ. Res. 19: 1011–1021, 1966.
 184. Patel, D. J., and D. L. Fry. The elastic symmetry of arterial segments in dogs. Circ. Res. 24: 1–8, 1969.
 185. Patel, D. J., J. C. Greenfield, and D. L. Fry. In vivo pressure‐length‐radius relationship of certain blood vessels in man and dog. In: Pulsatile Blood Flow. Int. Symp. Pulsatile Blood Flow, edited by E. O. Attinger. Philadelphia, PA: McGraw‐Hill, 1963, p. 293–306.
 186. Patel, D. J., and J. S. Janicki. Static elastic properties of the left coronary circumflex artery and the common carotid artery in dogs. Circ. Res. 27: 149–158, 1970.
 187. Patel, D. J., J. S. Janicki, and T. E. Carew. Static anisotropic elastic properties of the aorta in living dogs. Circ. Res. 25: 765–779, 1969.
 188. Patel, D. J., J. S. Janicki, R. N. Vaishnav, and J. T. Young. Dynamic anisotropic viscoelastic properties of the aorta in living dogs. Circ. Res. 32: 93–107, 1973.
 189. Patel, D. J., W. K. Tucker, and J. S. Janicki. Dynamic elastic properties of the aorta in radial direction. J. Appl. Physiol. 28: 578–582, 1970.
 190. Paul, R. J., J. W. Peterson, and S. R. Caplan. Oxygen consumption rate in vascular smooth muscle: relation to isometric tension. Biochim. Biophys. Acta 305: 474–480, 1973.
 191. Peachey, L. D., and K. R. Porter. Intracellular impulse conduction in muscle cells. Science 129: 721–722, 1959.
 192. Peiper, U., P. Klemt, and R. Schleupner. The temperature dependence of parallel and series elastic elements in the vascular smooth muscle of the rat portal vein. Pfluegers Arch. 378: 25–30, 1978.
 193. Peterson, L. H., R. E. Jensen, and R. Parnell. Mechanical properties of arteries in vivo. Circ. Res. 8: 622–639, 1960.
 194. Peterson, J. W., and R. J. Paul. Effects of initial length and active shortening on vascular smooth muscle contractility. Am. J. Physiol. 227: 1019–1024, 1974.
 195. Price, J. M., D. L. Davis, and E. B. Knauss. Length‐dependent sensitivity in vascular smooth muscle. Am. J. Physiol. 241 (Heart Circ. Physiol. 10): H557–H563, 1981.
 196. Pynadath, T. I., and D. P. Mukherjee. Dynamic mechanical properties of atherosclerotic aorta: a correlation between the cholesterol ester content and the viscoelastic properties of atherosclerotic aorta. Atherosclerosis 26: 311–318, 1977.
 197. Remington, J. W. Hysteresis loop behavior of the aorta and other extensible tissues. Am. J. Physiol. 180: 83–95, 1955.
 198. Remington, J. W., W. F. Hamilton, and P. Dow. Some difficulties involved in the prediction of the stroke volume from the pulse wave velocity. Am. J. Physiol. 144: 536–545, 1945.
 199. Remington, J. W., and L. J. O'Brien. Construction of aortic flow pulse from pressure pulse. Am. J. Physiol. 218: 437–447, 1970.
 200. Reuterwall, O. P. Über die Elastizität der Gefaswande und die Methode ihrer naheren Prufung. Acta Med. Scand. Suppl. 2: 1–175, 1921.
 201. Roach, M. R., and A. C. Burton. The reason for the shape of the distensibility curves of arteries. Can. J. Biochem. Physiol. 35: 681–690, 1957.
 202. Ruegg, J. C. Smooth muscle tone. Physiol. Rev. 51: 201–248, 1971.
 203. Samila, Z. J., and S. A. Carter. The effect of age on the unfolding of elastin lamellae and collagen fibers with stretch in human carotid arteries. Can. J. Physiol. Pharmacol. 59: 1050–1057, 1981.
 204. Schmid‐Schonbein, H. Microrheology of erythrocytes, blood viscosity, and the distribution of blood flow in the microcirculation. In: Cardiovascular Physiology II, edited by A. C. Guyton and A. W. Cowley. Baltimore, MD: University Park, 1976, vol. 9, p. 1–62. (Int. Rev. Physiol. Ser.)
 205. Schonfeld, D., H. B. Atabek, and D. J. Patel. Geometry and elastic response of the aorto‐iliac junction. J. Biomech. 12: 483–489, 1979.
 206. Seidel, C. L., and R. A. Murphy. Stress relaxation in hog carotid artery as related to contractile activity. Blood Vessels 13: 78–91, 1976.
 207. Shadwick, R. E. and J. M. Gosline. Elastic arteries in invertebrates: mechanics of the octopus aorta. Science 213: 759–761, 1981.
 208. Siegman, M. J., T. M. Butler, S. U. Mooers, and R. E. Davies. Calcium‐dependent resistance to stretch and stress relaxation in resting smooth muscles. Am. J. Physiol. 231: 1501–1507, 1976.
 209. Simon, B. R., A. S. Kobayashi, E. Strandness, and C. A. Wiederhielm. Reevaluation of arterial constitutive relations. Circ. Res. 30: 491–500, 1972.
 210. Simon, B. R., A. S. Kobayashi, C. A. Wiederhielm, and D. E. Strandness. Deformation of the arterial vasa vasorum at normal and hypertensive pressures. J. Biomech. 6: 349–359, 1973.
 211. Smith, R. A., W. E. Stehbens, and P. Weber. Hemodynamically‐induced increase in soluble collagen in the anastomosed veins of experimental arteriovenous fistulae. Atherosclerosis 23: 429–436, 1976.
 212. Sobin, S., and H. M. Tremer. Cylindricity of the arterial tree in the dog and cat (Abstract). Federation Proc. 39: 269, 1980.
 213. Sottiurai, V., W. J. Fry, and J. C. Stanley. Ultrastructural characteristics of experimental arterial medial fibroplasia induced by vasa vasorum occlusion. J. Surg. Res. 24: 169–177, 1978.
 214. Sottiurai, V., P. Kollros, M. B. Mathews, C. K. Zarins, and S. Glagov. Morphologic alteration of smooth muscle cells by cyclic stretching. J. Surg. Res. In press.
 215. Sparks, H. V., Jr., and D. F. Bohr. Effect of stretch on passive tension and contractility of isolated vascular smooth muscle. Am. J. Physiol. 202: 835–840, 1962.
 216. Speden, R. N. The effect of initial strip length on the nor‐adrenaline‐induced isometric contraction of arterial strips. J. Physiol. London 154: 15–25, 1960.
 217. Speden, R. N. The maintenance of arterial constriction at different transmural pressures. J. Physiol. London 229: 361–381, 1973.
 218. Speden, R. N. Muscle load and constriction of the rabbit ear artery. J. Physiol. London 248: 531–553, 1975.
 219. Speden, R. N., and D. J. Freckelton. Constriction of arteries at high transmural pressures. Circ. Res. 26, Suppl. 2: 99–111, 1970.
 220. Stromberg, D. D., and C. A. Wiederhielm. Viscoelastic description of a collagenous tissue in simple elongation. J. Appl. Physiol. 26: 857–862, 1969.
 221. Sumner, D. S., D. E. Hokanson, and D. E. Strandness, Jr. Arterial walls before and after endarterectomy. Arch. Surg. Chicago 99: 606–611, 1969.
 222. Sumner, D. S., D. E. Hokanson, and D. E. Strandness, Jr. Stress‐strain characteristics and collagen‐elastin content of abdominal aortic aneurysms. Surg. Gynecol. Obstet. 130: 459–466, 1970.
 223. Swanson, R. J., F. N. Littooy, T. K. Hunt, and R. J. Stoney. Laparotomy as a precipitating factor in rupture of intra‐abdominal aneurysms. Arch. Surg. Chicago 115: 299–304, 1980.
 224. Takeda, K., and R. D. Buñag. Augmented sympathetic nerve activity and pressor responses in DOCA hypertensive rats. Hypertension 2: 97–102, 1980.
 225. Tickner, E. G., and A. H. Sacks. A theory for the static elastic behavior of blood vessels. Biorheology 4: 147–168, 1967.
 226. Tobian, L., R. Olson, and G. Chesley. Water content of arteriolar wall in renovascular hypertension. Am. J. Physiol. 216: 22–24, 1969.
 227. Torrance, H. B., and S. Schwatz. The elastic behavior of the arterial wall. J. R. Coll. Surg. Edinburgh 7: 55–60, 1961.
 228. Uchida, E., D. F. Bohr, and S. W. Hoobler. A method for studying isolated resistance vessels from rabbit mesentery and brain and their responses to drugs. Circ. Res. 21: 525–536, 1967.
 229. Urry, D. W. Molecular perspectives of vascular wall structure and disease: the elastic component. Perspect. Biol. Med. 21: 265–295, 1978.
 230. Vaishnav, R. N., J. T. Young, J. S. Janicki, and D. J. Patel. Non‐linear anisotropic elastic properties of the canine aorta. Biophys. J. 12: 1008–1027, 1972.
 231. Vaishnav, R. N., J. T. Young, and D. J. Patel. Distribution of stresses and of strain‐energy density through the wall thickness in a canine aortic segment. Circ. Res. 32: 577–583, 1973.
 232. Van Citters, R. L., B. M. Wagner, and R. F. Rushmer. Architecture of small arteries during vasoconstriction. Circ. Res. 10: 668–675, 1962.
 233. Vonderlage, M. Untersuchungen über die mechanischen Eigenschaften von Streifenpräparaten verschiedener Schnittrichtung aus der Aorta abdominalis des Kaninchens. Pfluegers Arch. Gesamte Physiol. Menschen Tiere 301: 320–328, 1968.
 234. Wagner, R., and E. Kapal. Über Eigenschaften des Aortenwindkessels. Z. Mitteilung. Z. Biol. Munich 105: 263–292, 1952.
 235. Walmsley, J. G. Structure of small blood vessels related to smooth muscle mechanics. In: Vascular Neuroeffector Mechanisms, edited by J. A. Bevan, R. A. Maxwell, M. Fugiwara, S. Shibata, N. Toda, and K. Mohri. New York: Raven, in press.
 236. Warshaw, D. M., M. J. Mulvany, and W. Halpern. Mechanical and morphological properties of arterial resistance vessels in young and old spontaneously hypertensive rats. Circ. Res. 45: 250–259, 1979.
 237. Wesley, R. L. R., R. N. Vaishnav, J. C. A. Fuchs, D. J. Patel, and J. C. Greenfield, Jr. Static linear and nonlinear elastic properties of normal and arterialized venous tissue in dog and man. Circ. Res. 4: 509–520, 1975.
 238. Wezler, K., and A. Böger. Die Feststellung und Beurteilung der Elastizität zentraler und peripherer Arterien am Lebenden. Arch. Exp. Pathol. Pharmakol. 180: 381–400, 1936.
 239. Wiggers, C. J., and R. Wégria. Active changes in size and distensibility of the aorta during acute hypertension. Am. J. Physiol. 124: 603–611, 1938.
 240. Wilens, S. L., J. A. Malcolm, and J. M. Vazquez. Experimental infarction (medial necrosis) of the dog's aorta. Am. J. Pathol. 47: 695–711, 1965.
 241. Wolinsky, H. Response of the rat aortic media to hypertension: morphological and chemical studies. Circ. Res. 26: 507–449, 1970.
 242. Wolinsky, H. A proposal linking clearance of circulating lipoproteins to tissue metabolic activity as a basis for understanding atherogenesis. Circ. Res. 47: 301–311, 1980.
 243. Wolinsky, H., and S. Glagov. Structural basis for the static mechanical properties of the aortic media. Circ. Res. 14: 400–413, 1964.
 244. Wolinsky, H., and S. Glagov. Lamellar unit of aortic medial structure and function in mammals. Circ. Res. 20: 99–111, 1967.
 245. Wolinsky, H., and S. Glagov. Nature of species differences in the medial distribution of aortic vasa vasorum in mammals. Circ. Res. 20: 409–421, 1967.
 246. Zatzman, M., R. W. Stacy, J. Randall, and A. Eberstein. Time course of stress relaxation in isolated arterial segments. Am. J. Physiol. 177: 299–302, 1954.

Related Articles:

Pulmonary Vascular Disease

Contact Editor

Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite

Philip B. Dobrin. Vascular Mechanics. Compr Physiol 2011, Supplement 8: Handbook of Physiology, The Cardiovascular System, Peripheral Circulation and Organ Blood Flow: 65-102. First published in print 1983. doi: 10.1002/cphy.cp020303