Effects of Caffeine and Nicotine on Lumbriculus Variegatus

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Effects of Caffeine and Nicotine on Lumbriculus variegatus
INTRODUCTION
An experiment was conducted to study and explore the circulatory system by exposing Lumbriculus variegatus, black worms, to household drugs. Lumbriculus variegatus was chosen as the experimental organism because of their transparent bodies and their simple physiology. Their transparent bodies help the experimenters to easily see their pulse. Another reason for choosing this specific organism is their body structure—large surface area to size ratio. This feature allows the substances, such as the household drugs, to easily enter their body which then can affect their health.(1) The household drugs used in this experiment were decaffeinated coffee, tea, instant coffee and tobacco along with caffeine and nicotine. As we increase the concentration of caffeine, there will be an increase in the change in pulsation rates of the L. variegatus. The reason that the pulsation rate increases with the intake of caffeine is because it increases the blood flow velocity in the middle cerebral artery, which in a way increases the pulsation rates.(5) Caffeine is known as a stimulant, especially for the central nervous system; because “caffeine increases energy metabolism throughout the brain but decreases at the same time cerebral blood flow.”(4) Caffeine also acts as an inhibitor for adenosine, which is what allows it to be a stimulant.(2) As we increase the concentration of nicotine, there will also be an increase and right after the maximum change in pulsation rates of the L. variegatus there will be a decrease which will eventually hit 0 beats per minutes. The reason the pulsation rate increases and then decreases with the intake of nicotine is because it causes an increase in heartbeats and with a large doze it can result to no heartbeat at all.(3) Since decaffeinated coffee, tea, and instant coffee have caffeine in them there may be increase in the change of the pulsation rate of the L. variegatus. As we add tobacco, there may be an increase in the change in pulsation rates of the L. variegatus. The reason why we aren’t sure of how much the pulsation rate will go up by is because of the unknown amounts of caffeine in decaffeinated coffee, tea and instant coffee and the unknown amount of nicotine in the tobacco. Looking at the trends of the change in pulsation rates of different concentration of caffeine and the different concentrations of nicotine (taken in the first week), we can determine an estimated concentration of caffeine in decaffeinated coffee, tea and instant coffee and an estimated concentration of nicotine in tobacco (taken in the second week).

RESULTS

Figure 1. This graph shows the effects of different household drugs on pulsation rates. The columns represent the mean change in pulsation rates of different caffeine concentrations and decaffeinated coffee, tea and instant coffee. The error bars of each column represent the standard deviation for that treatment. The control group of the different concentrations of caffeine, taken in the first week, has a mean of -1.07 beats per minute and a standard deviation of 1.48. On the other hand, the control group of the different household drug treatments, taken in the second week, has a mean of 0.19 beats per minute and a standard deviation of 1.90.

Figure 2. This graph shows the effects of different household drugs on pulsation rates. The columns represent the average change in pulsation rates of different concentrations of nicotine and the unknown concentration of tobacco. The error bars of each column represent the standard deviation for that treatment. The control group of the different concentrations of nicotine, taken in the first week, has a mean of -1.07 beats per minute and a standard deviation of 1.48. On the other hand, the control group of the household drug tobacco, taken in the second week, has a mean of 0.19 beats per minute and a...
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