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

How much of solution to add 10ng of dna in a reaction, I dissolve 4µg of DN...

I dissolve 4µg of DNA in 1mL of water. How much of this solution would I need in order to add 10ng of DNA in a reaction?

Explain the characteristics of agar- agar, Explain the Characteristics of A...

Explain the Characteristics of Agar- Agar? There are many characteristics, which make agar-agar, an ideal solidifying agent. These are: (a) It has high gel strength, so it c

Chemical element is the central in the chlorophyll molecule, Q. Which chemi...

Q. Which chemical element is the central in the chlorophyll molecule? The chemical element that is the central in the chlorophyll molecule is magnesium. One atom of magnesium

Enzymes, what is the composition of enzymes ?

what is the composition of enzymes ?

The kidney, diseases of the kidney and their remedies

diseases of the kidney and their remedies

Biomaterials and osseointegration, During the last 90 years, man-made mater...

During the last 90 years, man-made materials and devices have been developed to replace parts of living systems in the human body. These special materials function in intimate cont

Explain the salient feature of genetic code, The one aspect which is not a ...

The one aspect which is not a salient feature of genetic code, is its being: 1. Degenerate 2. Ambiguous 3. Universal 4. Specific Ambiguous

Define the beer''s law - nutritional biochemistry, Define the Beer's Law -...

Define the Beer's Law - Nutritional  Biochemistry? Beer's law states that the concentration of a substance is directly proportional to the amount of light absorbed or inversely

What is meant by the arch reflex, What is meant by the arch reflex? In ...

What is meant by the arch reflex? In some situations the movement of the skeletal striated muscles does not depend upon commands of the superior motor neurons, i.e., it is not

What are the three main types of nitrogen wastes, What are the three main t...

What are the three main types of nitrogen wastes excreted by living beings? The major nitrogen wastes excreted by living beings are ammonia, uric acid and urea. Living beings t

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