scholarly journals Shear stress is normalized in glomerular capillaries following ⅚ nephrectomy

2015 ◽  
Vol 308 (6) ◽  
pp. F588-F593 ◽  
Author(s):  
Nicholas Ferrell ◽  
Ruben M. Sandoval ◽  
Aihua Bian ◽  
Silvia B. Campos-Bilderback ◽  
Bruce A. Molitoris ◽  
...  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Blood Rheology ◽  
Capillary Blood ◽  
Capillary Wall ◽  
Capillary Blood Flow ◽  
Glomerular Capillary ◽  
Glomerular Capillaries

Loss of significant functional renal mass results in compensatory structural and hemodynamic adaptations in the nephron. While these changes have been characterized in several injury models, how they affect hemodynamic forces at the glomerular capillary wall has not been adequately characterized, despite their potential physiological significance. Therefore, we used intravital multiphoton microscopy to measure the velocity of red blood cells in individual glomerular capillaries of normal rats and rats subjected to ⅚ nephrectomy. Glomerular capillary blood flow rate and wall shear stress were then estimated using previously established experimental and mathematical models to account for changes in hematocrit and blood rheology in small vessels. We found little change in the hemodynamic parameters in glomerular capillaries immediately following injury. At 2 wk postnephrectomy, significant changes in individual capillary blood flow velocity and volume flow rate were present. Despite these changes, estimated capillary wall shear stress was unchanged. This was a result of an increase in capillary diameter and changes in capillary blood rheology in nephrectomized rats.

scholarly journals Analysis of Flow Characteristics of the Blood Flowing through an Inclined Tapered Porous Artery with Mild Stenosis under the Influence of an Inclined Magnetic Field

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Neetu Srivastava
Keyword(s):  
Magnetic Field ◽  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Volumetric Flow Rate ◽  
Mhd Equations ◽  
Inclined Magnetic Field ◽  
Wall Shear

Analytical investigation of MHD blood flow in a porous inclined stenotic artery under the influence of the inclined magnetic field has been done. Blood is considered as an electrically conducting Newtonian fluid. The physics of the problem is described by the usual MHD equations along with appropriate boundary conditions. The flow governing equations are finally transformed to nonhomogeneous second-order ordinary differential equations. This model is consistent with the principles of magnetohydrodynamics. Analytical expressions for the velocity profile, volumetric flow rate, wall shear stress, and pressure gradient have been derived. Blood flow characteristics are computed for a specific set of values of the different parameters involved in the model analysis and are presented graphically. Some of the obtained results show that the flow patterns in converging region (ξ<0), diverging region (ξ>0), and nontapered region (ξ=0) are effectively influenced by the presence of magnetic field and change in inclination of artery as well as magnetic field. There is also a significant effect of permeability on the wall shear stress as well as volumetric flow rate.

scholarly journals Blood flow rate and wall shear stress in seven major cephalic arteries of humans

2019 ◽  
Vol 236 (3) ◽  
pp. 522-530
Author(s):  
Roger S. Seymour ◽  
Qiaohui Hu ◽  
Edward P. Snelling
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Blood Flow Rate ◽  
Wall Shear

scholarly journals The Effect of Slip Velocity on Unsteady Peristalsis MHD Blood Flow through a Constricted Artery Experiencing Body Acceleration

2019 ◽  
Vol 24 (3) ◽  
pp. 645-659 ◽  
Author(s):  
J. Nandal ◽  
S. Kumari ◽  
R. Rathee
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Axial Velocity ◽  
Slip Velocity ◽  
Volumetric Flow Rate ◽  
Body Acceleration ◽  
Stenosed Artery ◽  
Flow Through

Abstract In this analysis, we present a theoretical study to examine the combined effect of both slip velocity and periodic body acceleration on an unsteady generalized non-Newtonian blood flow through a stenosed artery with permeable wall. A constant transverse magnetic field is applied on the peristaltic flow of blood, treating it as an elastico-viscous, electrically conducting and incompressible fluid. Appropriate transformation methods are adopted to solve the unsteady non-Newtonian axially symmetric momentum equation in the cylindrical polar coordinate system with suitably prescribed conditions. To validate the applicability of the proposed analysis, analytical expressions for the axial velocity, fluid acceleration, wall shear stress and volumetric flow rate are computed and for having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted with varying values of flow variables, to analyse the influence of the axial velocity, wall shear stress and volumetric flow rate of streaming blood.

scholarly journals Effect of Externally Applied Transverse Magnetic Field on Unsteady Flow of Blood in Tapered Stenosed Artery

2019 ◽  
Vol 8 (6) ◽  
pp. 1398-1406
Keyword(s):  
Magnetic Field ◽  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Transverse Magnetic Field ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Volumetric Flow Rate ◽  
Transverse Magnetic ◽  
Stenosed Artery

The role of flow parameters of blood is very important in maintaining proper functioning of heart and in turn health body. Herschel–Bulkley fluid model is used for the proposed one-fluid blood flow model. The behavior of important blood flow characteristics wall shear stress, volumetric flow rate and axial velocity of the flow in tapered mild stenosed artery in the presence of externally applied transverse magnetic field is studied. A combination of analytical and numerical methods is used to solve the mathematical model of the system. We report the importance constant/variable viscosity of blood on unsteady flow in the proposed artery. Numerical results are reported for different values of the physical parameters of interest. It is observed with the help of graphs, that the flow characteristics wall shear stress, volumetric flow rate and axial velocity are affected in tapered stenosed artery and flow can be regulated with the help externally applied transverse magnetic field.

scholarly journals Suspension Two-Layered Blood Flow Through a Bell Shaped Stenosis in Arteries

2013 ◽  
Vol 10 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Amit Medhavi
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Plasma Model ◽  
Two Phase ◽  
Peripheral Layer ◽  
Flow Through ◽  
Flowing Blood

The present study concerns with the effects of the hematocrit and the peripheral layer on blood flow characteristics due to the presence of a bell shaped stenosis in arteries. To account for the hematocrit and the peripheral layer, the flowing blood has been represented by a two-layered macroscopic two-phase (i.e., a suspension of red cells in plasma) model. The expressions for the flow characteristics, namely, the velocity profiles, the flow rate, the impedance, the wall shear stress in the stenotic region and the shear stress at the stenosis throat have been derived. The quantitative effects of the hematocrit and the peripheral layer on these flow characteristics have been displayed graphically and discussed briefly.

scholarly journals Mathematical Modelling of Pulsatile Flow of Non-Newtonian Fluid Through a Constricted Artery

2021 ◽  
Vol 8 (3) ◽  
pp. 485-491
Author(s):  
Saktipada Nanda ◽  
Biswadip Basu Mallik ◽  
Samarpan Deb Majumder ◽  
Ramesh Kumar Karthick ◽  
Sagar Suman ◽  
...  
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Pressure Gradient ◽  
Power Law ◽  
Flow Rate ◽  
Computational Models ◽  
Research Work ◽  
Flow Parameters ◽  
Wall Shear

The research work explores blood flow into a stenosed artery, or one with abnormal growth within it. At the throats and at the critical height of the stenosis, mathematical and computational models have been developed to calculate the various associated parameters such as flow rate, pressure gradient, impedance, and wall shear stress. Modeling blood as a power law fluid showed the dependency of these quantities on temporal and spatial variables, as well as the frequency of the flow oscillation in time and the key parameters of the flow mechanism. The exponential curve is the geometry of the stenosis studied in this analysis. Analytical expressions for axial velocity, volumetric flow rate, pressure gradient, blood flow resistance, and shear stress have been computed and simulated in ANSYS to generate useful results with respect to variation of flow parameters with power law indices and also for comparison between Newtonian and Non- Newtonian models of blood. Upon investigation, it was found that wall shear stress (WSS) increases with stenosis depth and therefore, plays a crucial role in affecting other flow parameters. At power law index 0.6, the highest shear stress and flow velocity were encountered at approximately 7 Pa and 0.5 m/s respectively.

Inferior vena caval hemodynamics quantified in vivo at rest and during cycling exercise using magnetic resonance imaging

2003 ◽  
Vol 284 (4) ◽  
pp. H1161-H1167 ◽  
Author(s):  
Christopher P. Cheng ◽  
Robert J. Herfkens ◽  
Charles A. Taylor
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Shear Stress ◽  
Magnetic Resonance ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Inferior Vena ◽  
Resonance Imaging ◽  
Cycling Exercise ◽  
Wall Shear

Compared with the abdominal aorta, the hemodynamic environment in the inferior vena cava (IVC) is not well described. With the use of cine phase-contrast magnetic resonance imaging (MRI) and a custom MRI-compatible cycle in an open magnet, we quantified mean blood flow rate, wall shear stress, and cross-sectional lumen area in 11 young normal subjects at the supraceliac and infrarenal levels of the aorta and IVC at rest and during dynamic cycling exercise. Similar to the aorta, the IVC experienced significant increases in blood flow and wall shear stress as a result of exercise, with greater increases in the infrarenal level compared with the supraceliac level. At the infrarenal level during resting conditions, the IVC experienced higher mean flow rate than the aorta (1.2 ± 0.5 vs. 0.9 ± 0.4 l/min, P < 0.01) and higher mean wall shear stress than the aorta (2.0 ± 0.6 vs. 1.3 ± 0.6 dyn/cm2, P < 0.005). During exercise, wall shear stress remained higher in the IVC compared with the aorta, although not significantly. It was also observed that, whereas the aorta tapers inferiorly, the IVC tapers superiorly from the infrarenal to the supraceliac location. The hemodynamic and anatomic data of the IVC acquired in this study add to our understanding of the venous circulation and may be useful in a clinical setting.

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