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

What is the way of life of sponges, Q What is the way of life of sponges? ...

Q What is the way of life of sponges? Sponges live exclusively in an aquatic environment and they are attached by their base to a substrate fixation ground. Sponges are filteri

Explain the concept of atoms are associated, What is the logical order in w...

What is the logical order in which the concepts of atoms, molecules, cells... up to biosphere are associated? Atoms form molecules that structure cells that form tissues that f

Gametogenesis, The process of meiosis in animals is called gametogenesis .I...

The process of meiosis in animals is called gametogenesis .It takes place in the testis in male and ovary in female. Gametogenesis is divided into spermatogenesis (formation of

Central cell - synergids, Central Cell - Synergids It is the largest c...

Central Cell - Synergids It is the largest cell of the embryo sac, and the mother cell of the endosperm. The enlargement of the embryo sac after the last nuclear division is m

Examples of diseases which can be spread by drinking water, (a) Give two ex...

(a) Give two examples of diseases which can be spread by contaminated drinking water. (b) How can the spread of such diseases be prevented?   (a) Typhoid and cho

Define absorption, Define Absorption, Storage and Elimination of cyanocobal...

Define Absorption, Storage and Elimination of cyanocobalamin? Vitamin B 12 in food is bound to proteins and is only released by the action of a high 'Concentration of hydroch

Spore forming protozoan, Normal 0 false false false EN-...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

Rabies, Rabies Rabies, a fatal zoonotic viral disease of dogs, cats, m...

Rabies Rabies, a fatal zoonotic viral disease of dogs, cats, man and other mammals, causes an acute encephalomyelitis. The rabies virus belongs to the genus Lyssavirus in the

Bacteria, Bacteria The study of bacteria is called bacteriology. Bacte...

Bacteria The study of bacteria is called bacteriology. Bacteria are unicellular organisms and possess a distinct cell wall. They are included in kingdom Prokaryote. The bacter

Explain about the bulimia nervosa, Explain about the Bulimia Nervosa? B...

Explain about the Bulimia Nervosa? Bulimia Nervosa, as you may recall studying earlier, is a disorder characterized by episodes of binge eating or very rapid intake of large am

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