Measuring the effect of caffeine on Daphnia Heart rate PDF

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This is a review on the method used to measure the effect of caffeine on daphnia heart rate....

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DISCUSSING THE ARTICLE, VALIDITY AND RELIABILITY AND ACCURACY AND ITS USEFULNESS TO MY INVESTIGATIVE PROJECT. P1 & M1. A literature Review and Relevance to my investigative Project Article 1 The article was published by the University of California and reviewed by various departments of the University, such as the Department of exercise science, division of cardiovascular medicine, and human resource laboratory, the article has proven to be reliable by referencing lots of sources which was useful in the research. Although the sources are out of date, it can be argued that all works in science are built upon the foundation of past knowledge. The article is also reliable because it measures out what it sought out to measure. The article sought out to measure the effects of caffeine on blood pressure heart rate and forearm blood flow during dynamic exercise. The article showed reliability by giving in depth details to the method used to carry out the experiments and also justify the results obtained. The article gives account of the effects of caffeine on the cardiovascular system in comparison to the effect of a placebo [false drugfructose]. It suggested that under resting conditions, caffeine could cause increase in blood pressure and cardiovascular blood pressure systemic resistance, that caffeine can provoke elevation in plasma renin activity and concentration of plasma ANG II [Angiotensin II]. it also went further to support this point by explaining the antagonistic nature of caffeine to adenosine receptors. The article also showed reliability by postulating a hypothesis that caffeine induces rise in blood pressure during dynamic exercise associated with decrease in regional blood flow, that is forearm blood flow [FBF] and changes in concentration of ANG II plasma. The article also gives details of the method involved in testing the hypothesis. The method involves using live human subject which was regulated and approved by the University of California human subject committee. The method involved also showed a lot of controlled variables amongst the human subjects that proves that lots of work were put in place to ensure that physical and medical factors do not

alter the effects of caffeine. Such factors are ensuring the candidates are: qualified cyclists, age, weight body fat percentage, smoking habits, caffeine or drug habits, and for the women who participated variables like: menstrual cycle and contraceptive intake was also recorded. Oxygen intake was also recorded for all subjects. The article also stated that measures were in place to prevent unavoidable physical, biological and medical factors from causing Thermogenic and hemodynamic alterations such as carrying out the female protocols during the follicular process of menses and two sessions in a 10-day period. Performing a diet monitoring per week uses food processor II [E.S.H.A version 2.1 Macintosh] to access intake of caffeine and also carrying each session with a period of four days apart to allow the re-in sensitization of the body to caffeine. The article also employed quantitative and qualitative analysis to explain the results. The results states that men and women have same response to caffeine. The graph employed by the article also explained the result obtain and suggest that caffeine intake during exercise causes a noticeable difference to the placeable condition and the caffeine during rest also induces a difference to placeable conditions at rest. It showed that mean atrial pressure is affected by caffeine due to the noticeable difference with placeable conditions at 60-minute post injection and that the diastole blood pressure and heart rates were unaffected. The reason behind the reports were further discussed, it explains that the results obtained were evidence that caffeine affects the hemodynamic response to dynamic exercise by increasing the FBF [fore arm blood flow] and FVC [Forced Vital Capacity] and enhances increase of ANG II. It was also suggested that the action of caffeine on FBF, FVC, and ANG II was caused by reduction in plasma volume induced by mild diuretic effects of caffeine and also causes glomerular filtration rates and inhibition of tubular reabsorption. However, when compared to other studies from reference sources where found not to be supported. So, another explanation was suggested which was that caffeine causes vessel constriction in the skeletal muscles. This was supported by other resource. Ideas discussed showing reliability and transparency was all ideas and results were communicated in the article even if it was not in line with other sources. The article is valid

because of its numerous sources and references of information as it put forward and discussed the results [Jason, W, et al].

Discussing how useful the article is. Article 1 The article is useful because it provides a background knowledge of key areas like caffeine and its effects to Organism from a human perspective. Although this experiment is to test for the effects of caffeine on a simple Organism daphnia. The article allows me to compare similarities between the effects of caffeine on human with the effect simple organism. The article allows me to make tentative hypothesis and also what I will be testing and the questions are i will or should be answering as I carry out my experiment. The article has prepared me enough to understand certain variability and that I should meticulously controls those variables like temperature in order to get accurate results. The article has also exposed me and given information on certain areas in the human cardiovascular system allowing me to understand the mechanism, the hormones involved in blood flow, key technologies like : fbf, ANG II, MAP and so on. This is very useful in academic work aside from this experiment

Article 2 The article two has showed validity and reliability on the following account discussed in subsequent progress below. The article is reliable because the main objective was to measure and comment on the effect of ethanol, nicotine and caffeine at three concentration levels and at a time frame of 10 minutes interval and also to determine whether the effect could be reversed or not.

The article also displayed reliability and validity by referencing published reports by authors which could serve as a guide to experiment performed later on [Baylor 1942, Campbell ET al., foster 1997 and Webb and Solomon, 1941] where sources referred to in this article. The procedure or method used in the conduct of this experiment on the daphnia heart rate was based on a source which was reviewed [Baylor, 1942] To obtain accuracy in counting really fast definite heart rates was counted using an iMovie slow motion mode video. The article also showed reliability and accuracy by providing measures of a controlled experiment for stop this controlled experiment showed the possibility possible limitations of the experiment, such as huge range of heartbeats of 92 - 521 in the daphnia. However, no explanation could be given to the huge differences in heartbeat, knowing this was very useful The article also showed reliability and validity by employing the quantitative and qualitative analysis to help explain the results of the experiments. The line chart providers statistical analysis that ethanol Lower the heart rate same as nicotine while caffeine raises the heart rate [Corotto, F, et al., 2010].

Discussing how useful the article is. Article 2 The article is an article that discusses the experiment of ethanol, nicotine and caffeine on daphnia heart rate. This article is useful because it gives me an overall guide as to the result I should get and also gives an explanation as to why. The article two test for two other substances that is, nicotine and ethanol. Allowing me to have an understanding of the effect as to what these substances can do because limited resources will not allow me to conduct the experiment on the effect of those substances on Daphnia myself. It gives a guide as to what concentration of caffeine to be tested on at what point is the effect of caffeine on daphnia not reversible.

The experiment methods are useful because it allows me to formulate a preliminary experimental procedure on how to correct my experiments. It has given me a clear better guide as to what independent variable dependent variable and to what variables to be controlled

P2 and M2 project proposal including hypothesis and potential limitations

Abstract. Trimethyl xanthine is known as caffeine with a chemical formula of C8H10N4O2. It is a stimulant drug which has same characteristics with illicit drugs like cocaine and heroin and part of which means it is addictive. But, at a very slow rate and with consistent caffeine consumption which is almost unavoidable as caffeine has been added to pills foods and drink. Caffeine occurs naturally in tea leaves, extras of coffee beans, and cocoa beans. It can also be found in energy drinks and beverage drinks. The amount of caffeine varies in chocolate bars according to the production companies' discretion. Caffeine is a white crystalline powder with a very bitter taste. In medicine, it is used as heart stimulant and mild diuretics. In 1400, it was a rare commodity and staple in the European and Asian account, leave containing caffeine were used as medicine. Today caffeine is used especially by students to stay awake at night. Also, in medicine caffeine are used as weight loss pills and caffeine treated with citrate of potassium can help premature babies or young children who has undergone surgery to breathe properly. In adults, caffeine is used in combination with other drugs to kick start those other drugs. In a finding conducted by Harvard University, those who consumed coffee were found to be at a lower risk of diabetes. When caffeine is consumed it will act as adenosine. Adenosine is a chemical created by the brain which attaches to never cells and slows down the nerve's activity. Adenosine can also cause blood pressure vessel dilation which also allows for more oxygen during sleep. Caffeine in the human system acts as adenosine by binding to the nerve cells, removing the ability of the nerve cells to recognize the adenosine chemicals which then causes the nerve cells to speed up their reaction. Caffeine also induces an effect on blood vessels by constricting them allowing less blood and oxygen to the brain. The condition is detected by the pituitary

gland and hormone is released as a form of emergency response to tell the adrenal gland to produce adrenaline. The adrenaline causes restlessness, pupils dilation, open airways, heartbeat faster, blood vessel to skin surface to constrict to slow blood flow and increased blood flow to the muscle, BP rises, blood flow to stomach slows and increases blood sugar level, muscle are ready for action.

Introduction Daphnia are known as water fleas which is used in this experiment because they are small simple organisms that can be stimulated by caffeine and also because of their transparent exoskeleton which makes heart beat visible under microscope. The daphnia is a small crustacean having a single compound eye, two doubly enhanced antenna and leaf like limbs. The heart rate of daphnia is about 180 beats per minute and it is pokiliothermic, that is its body temperature rises with the environment.

Aim; To investigate the effects of caffeine on dafna hatreds to support my hypothesis and experimental evidence

Preliminary Experiment preliminary experiment was conducted firstly to familiarise myself with the apparatus involved and understand the possible limitation and how to address them in actual experiments. This experiment was done in order to test the required concentration of the caffeine to be used. It also provided me with information in formulating my risk assessment and safety data sheets. It provided me with adequate precautionary measures when dealing with apparatus. It provided me with adequate precautionary measures when dealing with the actual experiment and important of certain concepts like usefulness of surface tension and not putting the slide over the daphnia when viewing in the microscope as this can killed daphnia.

The preliminary experiment allows for room for improvements on the actual experiment as some equipment was substituted depending on the availability, accuracy and user friendliness. I do consider my result from this experiment to be rough and has huge variability because I only use water just to familiarise myself with the experiment.

Preliminary method

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On the cavity slide place strands of cotton wool

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using the prepared take out the daphnia and place them on the cotton wool

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add two drops of distilled water

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do not cover the slide, place on the microscope and focus the microscope

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using a timer, and a pencil tap record the heart rate of the daphnia by tapping on a pie of plain white paper with pencil when heart beat is seen

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collect the result of the three trials and find the mean

The Result and The Limitations The following result was gotten from the experiment

Limitations 

The pencil tap method proved to be inefficient cause of the very fast daphnia heartbeats and a few times I skipped a bit.

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Placing the daphnia from the pond water directly to the cavity slide adds more water than necessary and as such surface tension cannot be utilized.

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The timer did not always start and stop accurately as sometimes it took few seconds to focus and count the heart beats but the timer had already started before that time

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I was faced with the decision to either use a microscope which uses a mirror as its light source. How that works is by reflecting light from the room onto the slide. But, the problem was even if the room was well lit the microscope still suffers from poor lightning,

also there was a problem of properly directing the lights onto the slide using the law of angle of incidence and angle of reflection. 

The other limitation was that I could use a microscope which has a filament lamp as its light source but this lights bulb, is a source of heat and warms up the slide which creates another new ecosystem for daphnia and affects the accuracy of experiments.

Possible Solutions and Decision for the Experiment. After careful analysis I employed my problem-solving skills to overcome the limitations and also make some ethical decisions in situations that require I choose with discretion. The possible solution and decision are what I refer to as problem solving measures. 1. In order to overcome the timer's error and inadequacy of the pencil tap method, I decided to use my iPhone to do a recording for 15 seconds to record their heartbeats on the microscope and process into a slow mode video which I could count at a later time. This was really convenient and I could do this in a more comfortable position and I was able to recount heartbeat from one video as many times as I want to get a consistent value of heartbeat from that video 2. I also decided to have a Petri dish. The Petri dish is clean, the people it is used to carry pond water that contains daphnia To the Petri dish. It is then used to transfer the daphnia from the Petri dish to the prepared cavity slide. This prevent excess water on the cavity slide and also and shows only daphnia is transferred at a time. This removes the need to have to dab with a paper towel. 3. I decided to use a microscope with a filament lamp as light source. Since I only need to carry out the experiment for one daphnia because of the iPhone slow motion recording and also because I need sufficient light for the phone camera to focus

Apparatus 

microscope,

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cavity slide,

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culture of daphnia,

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distilled water,

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iPhone,

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caffeine solution,

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cotton wool ,

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Petri-dish,

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pipettes,

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6 test tube,

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stop Clock,

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paper towel,

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Test tube Holder

Preparation of Caffeine Solution six test tubes that are labelled A, [0.1 M]- 90% water and 10% caffeine B, [0.2 M] - 80% water and 20% cafdeine C, [ 0.3M] - 70% water and 30% caffeine D, [0.4 M] - 60% water and 40% caffeine E, [0.5 M] - 50% Water and 50% caffeine Y, [0.0 M]- 100% distilled water Z - pond water Ethical consideration I won't be going higher than 0.5 M because of I want to avoid over-stressing the daphnia which can cause their death

Method

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set up your equipment with Microscope plugged into the wall socket, cavity slides are prepared by placing strand of cotton wool on the 12 cavity slides and storing the cavity slide at a secure location on a tissue paper on the work surface for easy access. Ensure the test tubes we containing the solution are placed in test tube holders.

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Using a pipette transfer daphnia to the petri Dish, if more than two daphnia was transferred to the Petri dish transfer the excess back. Using pipette to take daphnia from the Petri dish and transfer to the prepared cavity slide and had two drops of distilled water allowed for five minutes to allow the daphnia too adjust to the new environment of distilled water.

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Turn on the microscope and focus the microscope on the cavity slide using a phone camera record and process in slow motion, the heartbeat of daphnia through the lens do this for 15 seconds

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repeat the experiment for other test tubes

Precaution 

avoid putting on the microscope for too long in fact it should be turned on and off only when in use to prevent hitting up the slide

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avoid using cotton wool in excess in preparing the cavity slide too much continued prevents light from reaching the daphnia. The cotton wool is just to prevent them daphnia from moving. Work in a clean environment. Use testing orders to prevent solution from spilling. Work on this table surface.

Result Concerntrati on (mole, M) 0 pond water 0.1 0.2 0.3 0.4 0.5

Daphnia 1 beat per 15 seconds 58 60 56 57 60 58 63

Daphnia 2 beat per 15 second 56 58 60 61 60 64 67

Daphnia 1 bpm 232 240 224 230 240 232 252

Daphnia 2 bpm 224 234 240 244 240 256 268

mean 228 237 232 237 240 244 260

Interpretation and conclusion From the graph It is evident that increase in the concentration of caffeine increases the heart rate. Therefore this act as a support to my hypothesis which states that cafe increases heart rate and this was also supported by the article revealed in appendix one appendix 2 because we know caffeine in the human system acts as adenosine by binding to the nerve cells, removing the ability of the nerve cells to recognize the adenosine chemicals which then causes the nerve cells to speed up their reaction. Caffeine also induces an effect on blood vessels by constricting them allowing less blood and oxygen to the brain. The condition is detected by the pituitary gland and hormone is released as a form of emergency response to tell the adrenal gland to produce adrenaline. The adrenaline causes restlessness, pupils dilation, open airways, heartbeat faster, blood vessel to skin surface to constrict to slow blood flow and increased blood flow to the muscle, BP rises, blood flow to stomach slows and increases blood sugar level, muscle are ready for action.

possible errors

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overheating of the slide by the filament bulb light source working out the concentration of caffeine proved difficult which can also be a source of error Although familiarising myself wit...