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Affect of caffeine on heart rate of Daphnia

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Introduction

Investigating the affect of caffeine on the heart rate of daphnia This experiment will be carried out to investigate the affect on the heart rate of daphnia under different concentrations of caffeine. Caffeine's are produced as insecticides. Cocoa, coffee and tea in Asia have all been used for hundreds of years to produce 'pick me up' drinks containing caffeine. These days, caffeine is also used as a flavour enhancer in a wide range of cola and other soft drinks. In addition, it has medicinal uses in aspirin preparations and is found in weight-loss drugs and as a stimulant in students' exam-time favourites like Red Bull. In humans, caffeine acts as a stimulant drug, causing increased amounts of stimulatory neurotransmitters to be released. Neurotransmitters are the nervous system's way of conveying messages between neurons, and also to muscle tissue. Some neurotransmitters that caffeine is known to increase the activity of are norepinephrine, dopamine, and serotonin. The increase in norepinphrine is what causes the heart rate to increase, Norepinephrine, is a powerfully stimulating neurotransmitter; it is associated with the 'fight or flight' response, which includes an increased heart rate. At high levels of consumption caffeine has been linked to restlessness, insomnia and anxiety, causing raised stress and blood pressure. This can lead to heart and circulation problems. ...read more.

Middle

I will also be doing a control experiment, to highlight that that the caffeine is having a direct affect on the daphnia, and to show that it cannot be any other factors affecting the BPM. Ethical issues arising from the experiment- Ethical issues may arise from this experiment as we are testing living things for the use of science. This may be controversial. Using fleas, may be considered cruel and also against animal rights. Furthermore, there is a small risk of killing the fleas. If this experiment is created on a mass scale, then there is a danger disrupting the food chain. Therefore we will analyse aspects of the experiment, which may endanger the daphnia and produce other methods which will be safer and less harmful for the daphnia. To ensure the daphnia is not killed- o Distilled water placed on the cavity for the flea, so it does not suffocate and instead of tap water because the chlorine may toxicate. o Strands of cotton wool will be added to restrict movement of the daphnia out of the slide. o Large sized pipettes will be used so the flies aren't squashed. o Distilled water will be added on the slip, so the flea is not poisoned. o A cover slip will not be used, which can squash the daphnia. ...read more.

Conclusion

The counting was made as accurate as possible, using the equipment we had. Plus, insteadof using pipette we could have used a burette measuring by one decimal place, this would have made the results much more accurate and the concentration accuracy could have been improved by using caffeine tablets. However, most aspects of the experiment were done accurately and changes were made to the apparatus, the experiment was repeated three times to give an average and overall is reliable and valid. The results are significant to us as we can now analyse the effect of caffeine on the heart, this may allow us research about the effect on circulatory system and factors which lead to cardiovascular disease. It implies that our caffeine consumption should be controlled as there could be further possible risks involved. However the results are quite limited in that, we do not know any other effects caffeine has on the heart apart from increasing the heart rate. It can only suggest to us or imply possible effects like causing stress e.t.c. Also, there were a few limitations in the apparatus, the counting technique was the least accurate part of the experiment, because it is considerably difficult to do, perhaps better equipment in counting would have increased the accuracy of the experiment. In conclusion we can see that the experiment has tested the hypothesis, and generally the results have been valid, reliable and useful, which reflects the experiment in general. ...read more.

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