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 usual morphological feature of nematodes, Q. What is the usual ...

Q. What is the usual morphological feature of nematodes that differentiates them from platyhelminthes? Nematodes are also called as roundworms. As the name indicates they are n

Blood circulation and respiration, A person is declared to be dead upon the...

A person is declared to be dead upon the irreversible cessation of spontaneous body functions: brain activity, or blood circulation and respiration. However, only about 1% of a per

Explain about gout disease, Q. Explain about Gout disease? Gout is a ch...

Q. Explain about Gout disease? Gout is a chronic disease due to an inherited abnormality of purine metabolism. What are purines? You may recall studying about purines and their

Pulmonary edema, Pulmonary edema occurs when movement of liquid from the bl...

Pulmonary edema occurs when movement of liquid from the blood to the interstitial space and/or into the alveoli exceeds the return of liquid to the blood and its drainage through t

What are nutritional care related to neurological disorder, What are nutrit...

What are nutritional Care related to Neurological Disorder? Let us then move on to the nutritional care. The important goals of nutritional care are to: prevent further

In which field dietetics related, The field of  dietetics can be related to...

The field of  dietetics can be related to: Nutrition care and intervention focused on the individual, and Nutrition care and intervention focused on the group.

Determine effects of probiotics on animals, Determine Effects of probiotics...

Determine Effects of probiotics on Animals? Let us briefly examine the effects that have been reported (remember most of it has been on animals): 1. In animals, probio

What is an argument that shows emergence of photosynthetic, What is an argu...

What is an argument that shows that the emergence of photosynthetic beings was crucial for life to reach the marine surface and later the dry land? The Ultraviolet radiation fr

Heart, Septa prevent oxygenated and deoxygenated blood. Give reason

Septa prevent oxygenated and deoxygenated blood. Give reason

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