One of the most important organs in the body is the heart. Of course, this organ is of great importance not only in humans but in all vertebrates. Blood, which carries nutrients, oxygen, and wastes from organ to organ within the body is pumped by the heart. Without the heart's pumping action, blood would simply remain stagnant within the vessels of the body, and any vertebrate in this condition would die off very quickly.
[...] We predicted that it would impair the action of acetylcholine, since it competes with its receptors. Materials and Methods Procedures were followed exactly as stated in Foundations of Biology: Cell and Organ Physiology (Faculty of the Department of Neurobiology and Behavior p. 92-97. Results As compared to the control, adding epinephrine sped up heart rate but, according to the readings, decreased contractile strength. Adding acetylcholine decreased heart rate. Atropine brought heart beat back up, even above the control, and adding acetylcholine right after atropine proved to be far less effective than adding acetylcholine by itself. [...]
[...] Epinephrine and norepinephrine, on the other hand, are released by the sympathetic system and excite heart muscle, causing it to contract harder and faster (Dilger, 96-97). Our hypothesis in this lab was that adding drops of these chemicals onto the open frog heart would cause changes in the heart's activity. Specifically, we predicted that epinephrine would speed up the heart rate and increase contractile strength, and that acetylcholine would slow down the heart rate. We also tested the effect of an alkaloid called atropine. [...]
[...] This is consistent with the reading on the ECG that shows an increase in the frequency of QRS peaks, indicating faster heartbeat. This effect of epinephrine contributes greatly to the fight-or-flight response in the human body. Increased heart rate allows more blood to be pumped faster to the blood vessels of the musculo-skeletal system, allowing the body to maneuver faster and stronger. The tensile reading of .2g from the tension graph shows that contractile strength dropped from the control of .4g. [...]
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