Cardiovascular Lab

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Cardiovascular Dynamics and the Cardiovascular Physiology experiments both have multiple goals. The first experiment aims to understand how blood flow, pressure gradient, and resistance relate to one another. To understand this, resistance and contributing factors, such as vessel radius, viscosity, and vessel length must be studied. The effects of vessel radius and stroke volume on the ventricular pump should also examined. The experiment also calls for an understanding of cardiovascular compensation. Pump mechanics are further understood through a design of further experiments. The Cardiovascular Physiology experiment attempts to understand the effects of parasympathetic and sympathetic nervous systems on the heart, through vagus nerve stimulation. Refractory periods and relative refractory periods will be studied in direct stimulations of the heart, as well as the five phases of the cardiac cycle. Lastly, the effects of temperature, hormones, and ions will be understood. Epinephrine, pilocarpine, atropine and digitalis are the hormones used to modify the heart. Sodium, potassium and calcium are the ions used in this experiment.

In the Vessel Resistance section for the Cardiovascular Dynamics experiment, two glass beakers, a tube connecting them and a pressure meter were used. The left beaker represented the heart, the right breaker represented the body and the tube was the artery. For the Pump Mechanics section, three glass beakers and two tubes were used, along with three pressure meters. There were also two valves, one representing the bicuspid valve and one representing the aortic semi-lunar valve. The left beaker simulated blood being pumped from the lungs, the middle beaker was the left side of the heart, and the right beaker represented the body. The left flow tube represented a vein and the right flow tube represented an artery. A suspended three chambered heart, an oscilloscope monitor, a heart tray and 23o Ringers solution were required for the Electrical Stimulation and Modifiers of the Heart section in the Cardiovascular Physiology experiment. The Electrical Stimulation section additionally needed Epinephrine, atropine, pilocarpine, digitalis, calcium ions, sodium ions and potassium ions The first section of the Cardiovascular Dynamics experiment measured Vessel Resistance. In the first activity, pressure was manipulated to measure its effects on blood flow. A starting pressure of 25 mm Hg was set in place and increments of 25 mm Hg was made, until a value of 225 mm Hg was reached. The second activity studied the effects of the tube radius (artery) on blood flow. The starting radius was 1.5 mm and it was increased by 1.0 mm, until a radius of 6.0 was reached. The third activity tested the effect of viscosity on blood flow. Blood viscosity started at 1.0 and increments of 1.0 were made to reach a blood viscosity of 6.0. The next activity observed the effect of vessel length on blood flow. Length started at 10 mm and increased by 10 mm, to reach a vessel length of 50 mm. The second section studied Pump Mechanics. In the fifth activity, the radius of the right flow tube was manipulated to measure the effects of vessel radius on the heart pump. The radius of the right flow tube started at 3.0 mm and was increased by 0.5 mm to arrive at 6.0 mm. Activity six manipulated stroke volume and determined its effect on the heart pump. Stroke volume was initially set in place for 10 ml and was increased by 10 ml to test a final stroke volume of 120 ml. Results from each test were recorded and plotted. Activity seven was carried out to examine the ways in which the cardiovascular system compensates for deficiencies. A baseline test was first done and the data was recorded. Then, the radius of the right low tube was decreased and the results of the test were recorded. Three tests were designed to compensate for the effects of the decreased radius of the right flow tube. In...
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