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

Sample titration for estimation of vitamin c in lemon juice, Define Sample ...

Define Sample Titration for Estimation of Vitamin c in Lemon Juice? Cut the lemon into two halves with a stainless steel knife. Remove the seeds. Squeeze the juice from half a

Functions of the musculoskeletal system, Q. What are the functions of the m...

Q. What are the functions of the musculoskeletal system? The musculoskeletal system has the functions of protecting and supporting organs, maintenance of the body spatial confo

What do you mean by ventricular arrhythmias, Q. What do you mean by Ventric...

Q. What do you mean by Ventricular Arrhythmias? Considerable disagreement exists regarding the significance of resting ventricular ectopic beats. In study comparing the coronar

Reproduction, REPRODUCTIO N - It is not only production of new ones...

REPRODUCTIO N - It is not only production of new ones to increases its number but a means for the survival of a population on earth. Main aim is "survival and continuati

Biology Question, Why is VeggieTales such a consistently high-quality progr...

Why is VeggieTales such a consistently high-quality program?

Concerning their permeability how are membranes classified, Q. Concerning t...

Q. Concerning their permeability how are membranes classified? Membranes can be classified as permeable, impermeable, selectively permeable or semipermeable. An impermeable

Extinction, EXTINCTIO N  - It refers to disappearance of a species from...

EXTINCTIO N  - It refers to disappearance of a species from earth when its last surviving member dies. Organic evolution not only creats new sps. but also eliminates some ol

Composition of body fluids, Composition of Body Fluids All body fluids...

Composition of Body Fluids All body fluids - plasma, interstitial and intracellular have one common feature i.e. they are formed mostly of water. You would be amazed to know t

What do you know about tricuspid stenosis, Q. What do you know about Tricus...

Q. What do you know about Tricuspid stenosis? It is rare disease, with rheumatic etiology seen in 90 per cent of cases. In patients with rheumatic mitral stenosis only 3-5 per

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