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Elasticity of blood vessels.

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Introduction

Elasticity of blood vessels Introduction There are many blood vessels in the body. There are two main ones, arteries and veins. These blood vessels are able to expand in order to let more blood flow through them. They also contract to help control the flow of blood. Blood is pumped out of the heart to the body via the arteries and the veins carry the blood back to the heart. When the blood is in the blood vessels, pressure is present. In the arteries the blood is at higher pressure than it is when in the veins, arteries also have thicker walls (due to the high pressure) than the walls of the veins. The elasticity of arteries is what sustains the pressure on the blood when the heart relaxes and keeps the blood flowing in a forward direction. In the following experiment, we observed the elasticity of veins and arteries so that we could determine the differences in elasticity and if this affects the pressure within the vessels. ...read more.

Middle

The length of the artery was then recorded. Thereafter the addition of weights continued until it reached 100g, at each time adding 10g, whilst recording the length at each new weight. Once this was completed, we then needed to remove 10g of weight at a time and then recorded the new length (if changed) of the artery. This then allowed us to work out the elasticity of the blood vessel. Again, the weights continued to be removed until all the weights were taken off. This entire method was carried out with three separate pieces of artery and then the exact same method with the veins. During this experiment there are possible sources of error, which might have made the results inaccurate and on the whole, the entire experiment unfair. The pieces of artery and vein were not of the same diameter or width; this altered the strength of the pieces. Reading the length of the blood vessel using a ruler proved to be difficult which meant that the length could easily have been misread and therefore inaccurate. ...read more.

Conclusion

Due to the vein not having a thick layer of elastic fibres, we can see that this would be the cause of the results reflecting the vein. The muscular walls of the vein are quite thin. Therefore reducing the strength of the blood vessel. The arteries have much more elastic tissue, and a smaller lumen. The arteries also have thick muscular walls. This would explain why the results are as they are in the graph above. It is clear that the arteries need to have more elastic fibres. The blood flows at high pressure through the arteries; therefore, if the arteries are slightly stretched due to the high pressure, the arteries need to return to their original size, whereas veins do not. The blood flows at low pressure through the veins, there is likely to be no damage to them (elastic damage) because they have valves. This means that veins do not need to have a high elasticity compared to the need of the arteries having high elasticity. As mentioned before, there were errors, which took place in this experiment. However taking three readings to calculate an average, rules out most of the errors. Melissa Osman 4 ...read more.

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