Viscosity - blood flow, Biology

Assignment Help:

Viscosity - Blood Flow

The resistance to flow in a tube results from inner friction in the fluid i.e. the viscosity. We all know that water and sugar syrup do not flow at the same rate from a bottle. We can say that water has low viscosity and syrup, a high viscosity. For convenience viscosity of a fluid is expressed relative to the viscosity of water. Blood plasma has a relative viscosity of 1.8 mostly as a result of the 7% dissolved proteins. Whole blood is more viscous because of the cells in it, at 37?C, relative viscosity of mammalian blood is between 3 and 4. Therefore, because of the presence of RBC blood behaves as though it is 3-4 times more viscous than water. However, blood does not behave as expected of a viscous fluid.

Its relative viscosity changes with decreasing radius of the blood vessels. In fact in tubes less than 0.3 mm in diameter the relative viscosity of blood approaches that of the plasma, therefore, it flows more easily. In flowing blood, we find that the red cells tend to accumulate in the centre. This accumulation leaves the wall relatively free of cells, therefore, the viscosity in the centre is more than at the sides. Since flow is inversely related to viscosity, flow at the walls will increase slightly and will decrease at the centre slightly. Another peculiar aspect of blood flow in capillaries is that often the capillary diameter is smaller than RBC and the RBCs easily change shape to pass through the capillary. This gives rise to a very different type of flow - bolus flow in which the red cells act as a plug that causes rapid increase in liquid along the walls of the capillary and thus help in the renewal of the diffusible substances in this layer.


Related Discussions:- Viscosity - blood flow

Define human beings need energy for basal metabolism, Define human beings n...

Define human beings need energy For Basal metabolism? This comprises a series of functions that are essential for life, such as cell function and replacement; the synthesis, se

Shifting attention by dopamine, Q. Shifting attention by Dopamine? Dopa...

Q. Shifting attention by Dopamine? Dopamine: Dopamine plays a pivotal role in aspects of shifting attention. Administration of D1/D2 receptor antagonist haloperidol impairs the

Explain risk factors and their role in cad, Explain risk factors and their ...

Explain risk factors and their role in cad ? The concept of risk factors constitutes a major advance for developing strategies to prevent CVD. The Framingham Heat Study played

What is the single tooth implant case, In Single Tooth Implant Case: a)...

In Single Tooth Implant Case: a) Vertical distance available between the crest of residual ridge to the opposing occlusal surface. At least 7 mm space is required to a cementab

Main parts into which a neuron can be divided, Q. What are the three main p...

Q. What are the three main parts into which a neuron can be divided? What are their respective functions? The three mains parts into which a neuron can be didactically divided

Find which of the following is most stable, Hydrogen ( h) has 1 electron; C...

Hydrogen ( h) has 1 electron; Carbon ( c) has 6 electrons, use the octet rule to determine which of the following is most stable. Note: some of these may have double bonds. A. O

Anther, Anther  is the top of a stamen's filament; divided into pollen sacs...

Anther  is the top of a stamen's filament; divided into pollen sacs in which the pollen grains are form.

State the definition of bio-medical waste, State the definition of Bio-medi...

State the definition of Bio-medical waste 'Bio-medical waste' means any solid and/or liquid waste including its container and any intermediate product, which is generated durin

What are benefits of increasing the growth of bifidobacteria, What are the ...

What are the benefits of increasing the growth of bifidobacteria? Bifidobacteria displaces potential pathogens selectively, showing an antibiotic like effect, which is unrelate

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd