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The human cardiovascular system consists of the heart, the blood, and a system of transporting vessels. A human heart has four chambers: a right and left atrium and a right and left ventricle. The fist-sized heart sits in its own sac (the pericardium) in the middle of the chest under the sternum. In most people, the apex of the heart points to the left. There are two circuits of simultaneous blood flow in humans: a pulmonary circuit and a systemic circuit. In the pulmonary circuit, the right ventricle pumps degenerated blood to the lungs for gas exchange.

At the same time, oxygenated blood that has come from the lungs o the left side of the heart is pumped to the bodes cells (the systemic circuit) for gas exchange. The degenerated blood is returned to the right side of the heart. Strenuous exercise causes a dramatic increase in blood flow to skeletal muscles that depend on the red blood cells to bring them the oxygen necessary for cellular respiration , which is the quantity of blood pumped from one’s heart and clinically measured per minute. There are several points in the body where the heart rate may be taken, but it is read clinically at the wrist over the radial artery.

Cardiac output is important because it determines one’s potentials for gas exchange and thus physical activities. Exercise over time increases one’s physical fitness. A way to measure fitness is by taking a blood pressure reading. Blood pressure is read by a device called a sphygmomanometer. Blood pressure is the force of blood moving along the elastic walls of arteries. The top number is the systolic reading, corresponding to the contraction phase of the heartbeat. The bottom number is the diastolic reading and corresponds to the relaxation phase of the heartbeat.

A healthy at-rest systolic reading for a young adult would be 110 to 120 mug (millimeters of mercury). A good at-rest diastolic reading would be 70 to 80 mug. It is measured clinically over the brachia artery using a blood pressure cuff. The premise behind this experiment is that as time elapses after exercise, the metabolic demands on our cardiac output will also lower. This is a direct relationship. Checking the heart rate after exercise is a way to gauge the demand for oxygen to our cells. The scientific method has no rigid format, but it has several vital components.

The observation of a phenomenon leads to a question which must be as free of preconceived bias as possible. This leads to the formation of a hypothesis, which is a tentative explanation for the possible cause of the observed phenomenon. The hypothesis is preferably worded as a prediction in an if-then format. Observation, study, and knowledge all contribute to the construction of the hypothesis. You also write a null hypothesis. This is a negative restatement of the hypothesis. We then develop an experiment which should yield data that either supports or refutes the hypothesis.

There re certain variables or factors to consider in constructing the experiment. The independent (x) variable is the variable which the experimenter manipulates. In this case, it is the time elapsed after exercise. Minutes elapsed represents levels of treatment. The dependent (y) variable) is the responding variable. In this case, respirations per minute comprises the y variable. Controlled variables are independent variables which must be kept constant in order to determine the effects of the independent variable being manipulated on the dependent variable.

Therefore, distracting the participants in any way should be avoided ND the timing of the treatments should be adhered to as closely as possible. Experimental error consists of intrinsic factors which may affect results of any experiment. They are always present. These are the variables which the experimenter cannot fully control or may even be unable to identify. This inevitable level of uncertainty bars proving anything in science. A separate individual who does not undergo exercise may be observed in order to compare his or her data from it with that of those receiving the treatment exercise. Such an individual is termed the control.

Tables present data obtained during the experiment. The variables should be plainly labeled and understandable. All of your readings should be displayed. Line graphs show the measured (continuous) relationship between the independent and dependent variable under scrutiny. There will always be a degree of uncertainty in any measured value. Never use a bar or pie graph for measured values. Conclusions are stated in terms of the null hypothesis. There are only two sentences written. The null hypothesis will be rejected if the expected results occur. The null hypothesis is accepted if the expected results do not occur.

Evidence is then acknowledged. Here follow the Lab Report Guidelines: The report is worth 50 points. 1. The report must be typed in 12 pet. Or larger type using only Times New Roman font. 2. It must be double spaced. 3. It is due at the beginning of your next regular lab period. 4. Except where the guideline specifies otherwise, use your own words. 5. Use the paragraphs format which follows and write the paragraphs in the order indicated. You will have a separate cover page (two points) with a proper title (one point). An example which you may use is The Effects of Exercise on Heart Rate.

Under the title, place your name, the date and time of your lab, and your instructor’s name (one point). Introduction: What is cardiac output (two points)? Why is adequate blood flow significant with respect to physical activity (two points)? Name the two circuits of blood flow in humans (two points). How do we measure cardiac output and at what clinical rate (two points)? Purpose of the experiment: Using your own words, state the reason or reasons why you carried out this experiment (four points). Hypothesis: After exercise, a person’s heart rate will progressively become lower (two points).

Null hypothesis: After exercise, a person’s heart rate will not progressively become lower (two points). (A strong word to the wise here! State these hypotheses exactly as directed! ) Procedure: In your own words, describe to your reader in the future how you and your partners carried out this experiment. List each step and state who performed what tasks, how those tasks were carried out, and in what order. You are telling your reader of the future how to replicate your procedure (four points). Results: There will be no narrative here. This section will consist of one table (six points) and one line graph (six points).

The table must be typed with all pertinent data, showing the relevant variables and labeled as appropriate. Use the following format as an example. Heart rate in respirations per minute Resting rate before exercise 74 Times after exercise < one minute > five minutes ten minutes 119 87 74 Now create a line graph that depicts the rates noted at each time after exercising. Suggest you use the supplied template, but you may create a graph by computer. You must show the averages and correctly depict the labels and axes. Use a straightedge to connect the dots. Any sloppiness will be penalized!

Conclusions: (Accept) (Reject) the null hypothesis (two points). There is data to suggest that after exercise, a person’s heart rate (will) (will not) progressively become lower (two points). Closing section: What is experimental error (two points)? What experimental errors might you have had during your experiment (two points)? Therefore, how might you improve the reliability of this experiment (two points)? Lastly, why is it that gathered data can never prove anything in science (two points)? Required reference (two points) (Note the style is from the PAP manual, 6th edition): Manes, S. E. (2013).

Cardiac lab handout. University of North Georgia. There will be a five point penalty for using the words “proof’ and “prove” as regards your procedure or results. Remember, you are only gathering data to either support or refute your hypothesis. Experimental error precludes proving anything in science. There will also be a five point penalty for not double-spacing your paper. Double space your table as well! There will also be a five point penalty for not using 12 pet. Type or larger. There will also be a five point penalty for not using Times New Roman font. I will in no case accept late or e-mailed ports.

It is your responsibility to ensure that your paper is submitted on time and in the proper format. Turn it in early if you need to. I strongly suggest that you keep a copy of your paper on disc with you at school at all times. As required, I retain possession of all papers for two years. If you forget, you will have lost a third of your lab course grade and I will strongly advise you to drop the lab course. Make no exceptions. I do want you to bring your paper to me in person and I will check it to provide you with immediate feedback about how to improve it to a 50/50 quality.

Students may enter the buildings on campus at 0700. I will be either in my office or preparing my class by 8:mama. You can email me to set up an appointment time as well if needed. Do not wait until just before class! I will not check them over e-mail, either! I will check your paper in person as many times as you need me to, time permitting. There is no reason for you not to earn a 100% by learning how to write a scientific paper. However, as with all things in life (this is not high school and no one will check up on you! ), you and only you are the one who determines your success or failure.

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