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

TAKHTAJANS classification, comparison between takhtajans and natural classi...

comparison between takhtajans and natural classification

Define nutrition counseling - management of eating disorders, Define Nutrit...

Define Nutrition Counseling - Management of Eating Disorders? Nutrition counseling can be used to accomplish a variety of goals, such as reducing behaviours related to the eati

Hindbrain - cerebellum, HIND BRAIN - 1 .       CEREBELLUM - Li...

HIND BRAIN - 1 .       CEREBELLUM - Little part, lies below the posterior part of cerebrum & above the medulla oblongeta. It conists of median lobe vermis & 2 lat

Peri operative myocardial infarction, Peri operative Myocardial Infarction ...

Peri operative Myocardial Infarction :  Peri operative Myocardial Infarction is diagnosed by the appearance of fresh Q waves. Non-Q, myocardial infarction is suspected when there

Explain the energy flow of ecology, Explain the energy flow of ecology? ...

Explain the energy flow of ecology? Energy flow: As you can see, energy flow is one way in an ecosystem. Energy is not recycled. The ultimate source of energy that powers eco

Explain adverse effects, Explain Adverse Effects Fluconazole is genera...

Explain Adverse Effects Fluconazole is generally well tolerated. Gastrointestinal distress and rash can happen. Stevens-Johnson syndrome, anaphylaxis and hepatic necrosis have

Primary prevention - preventive strategies for food allergy, Define Primary...

Define Primary Prevention - preventive strategies for Food Allergy? Focuses on blocking sensitization and development of IgE-mediated response. These strategies would be useful

Explain the drug effects on nutritional status, Explain the Drug Effects on...

Explain the Drug Effects on Nutritional Status? Drugs can affect nutritional status in a number of ways i.e. by enhancing excretion of certain nutrients, by interfering with nu

Basic calculations during the practical work in laboratory, Define Basic Ca...

Define Basic Calculations during the practical work in Laboratory? Some basic mathematical formulas and conversion factors are given herewith to help you in your calculations d

Kinds of succession - ecology, Kinds of Succession - Ecology The ecolo...

Kinds of Succession - Ecology The ecological succession can be broadly classified into two kinds, on the basis of the nature of the habitat. Figure: Kinds of Success

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