Air Pressure Lab Report
Variables Affecting Human Arterial Pressure and Pulse Pressure
BIOL 204-506
Remi Ben-Davies
Dashaun Lee, Amanda Easter, and Lynne Baker
April 9th, 2015
1
Introduction:
Purpose: The purpose of this experiment was to determine how different variables may affect arterial pressure and pulse rate. Two subjects were used as models for the tests. The first two tests required the use of sphygmomanometers and stethoscopes to measure the arterial pressure and pulse rate. The last test required sphygmomanometers, plethysmographs, and the iworx system. Postural change was used as the variable in the first test to examine the changes of arterial pressure and pulse rate in subject 1. The next test included exercise as the variable. Subject 2 was required to have their resting blood pressure and pulse rate measured after performing an exercise. …show more content…
The last test used cognitive stress as a variable. Subject 1 had their blood pressure and pulse rate measured while performing the cognitive stress test.
Background: To be able to transport the ideal amount of blood to the appropriate organ systems, the rhythm of the heart is controlled by many factors. Blood pressure plays a significant role in controlling heart rate. Blood pressure, defined as the amount of force that presses up against the blood vessel walls, can be measured in millimeter of mercury (mm HG). Systolic pressure is the amount of force that presses up against the blood vessel walls during ventricular contraction (systole), and diastolic pressure is the same; however it occurs during ventricular relaxation (diastole). Blood pressure is measured as systolic pressure/diastolic pressure and pulse pressure is the difference between those two. Pulse pressure can be “felt as a throbbing pulsation in an artery during systole” (Marieb & Hoehn 702). You can use the blood
2
pressure and pulse pressure to find the mean arterial pressure (MAP). MAP can be calculated with this formula: diastolic pressure + (pulse pressure/3). Pulse pressure is the difference between the systolic and diastolic pressure.
.
Hypothesis: Both subjects will have an average baseline pulse rate and MAP for the first two tests. The average MAP is 93 mm HG (80 + 40/3). The average pulse rate for men is 70-72 beats per minute (bpm); and the average for women is 78-83. Subject 1’s predicted pulse rate was 80 bpm. And subject 2’s baseline was 71 bpm. Reclining for three minutes will decrease the pulse rate to 77 bpm and the MAP to 91 mm Hg (78 + 40/3) because the heart is not fighting against gravity to transport blood. Standing up immediately after reclining for three minutes will increase the pulse rate to 85 bpm and the MAP to 95 mm Hg (82 + 40/3). The heart works hard to supply blood to the muscles that are quickly helping the subject to stand up. After standing for three minutes, the subject’s pulse rate and MAP will go back to normal.
Immediately after exercising during the second test, subject 2’s pulse rate and MAP will increase to 100 bpm and 112 mm Hg (95 + 50/3) respectively. The minute after exercising would decrease the MAP to 99 mm Hg and the pulse rate to 95 bpm. The MAP and pulse rate would respectively decrease to 97 mm Hg and 92 bpm in the next minute; and then to 95 mm Hg and 88 bpm in the following minute.
3
Subject 1’s baseline would have an average MAP of 93 mm Hg during the cognitive stress test. During task A of the test, the subject’s MAP and pulse rate would respectively increase to 94 mm Hg and 84 bpm. The pulse rate and MAP would then respectively increase to 86 bpm and 96 mm Hg during task B.
Results:
Postural changes: Subject 1’s blood pressure and pulse rate were recorded at baseline, after three minutes of reclining, immediately upon standing, and after standing for three minutes.
4
Exercise: Subject 2 was required to perform the step up exercise for five consecutive minutes. The subject’s blood pressure and pulse rate was measured immediately after the workout, one minute after the workout, two minutes after the workout, and three minutes after the workout. Cognitive Stress Test: Subject 1 had their baseline blood pressure and average pulse rate measured with the iworx system. This test required the subject to spell 15 words forward (task A) and 15 other words backward (task B) while having their blood pressure and pulse rate measured.
5 Discussion: Generally, most of the predicted baseline values were all wrong. The predicted baseline values that were used were calculated to be average values. The normal blood pressure is 120/80, which is why the average MAP value was chosen to be 93 mm Hg (80 + 40/3). The pulse rates were all within the normal limits depending on whether the subject was male or
female. Postural Changes: For some reason, the subject’s baseline pulse rate was higher than any other posture pulse rate. The reason for that fact may come from a random error of someone measuring the heart rate incorrectly and losing count somewhere along the process. However, the baseline MAP seemed reasonably logical, being the lowest value. The subject’s
6
pulse rate and MAP after reclining for three minutes were roughly similar to the predicted values. The predicted values of the subject standing immediately after reclining for three minutes were far inaccurate. The subject’s values after standing for three minutes were also fairly wrong because they were not the predicted, normal values. It was believed that a person’s pulse rate and MAP would increase while a person is standing because the heart would be working twice as hard to pump blood to the extremities allowing the person to stand up; however that is not the case. While lying down, heart rate and blood pressure stay at ease because there is no gravity resistance. Standing up quickly would lead to a decrease in venous return because the heart would be fighting gravity to the pull blood towards it. A decrease in venous return results in a decrease in ending diastolic volume and stroke volume. Ending diastolic volume is the amount of blood filled in the ventricles during diastole, and stroke volume is the amount of blood ejected from those ventricles per heartbeat. A decrease in stroke volume results in the decrease of cardiac output, which is the amount of blood ejected from the ventricles per minute. Decreased cardiac output causes a decrease in MAP.
Exercise: Although the subject 2’s MAP and pulse rate increased dramatically after the workout, it did not match up with the predicted values. The subject’s pulse rate immediately after exercising was predicted to be 100 bpm; however the observed value was 144 bpm. The MAP also off by 12 mm Hg. The predicted values were all inaccurate, but the concept was generally the same as the observed values. There was a random error recorded for the three
7
minute column, stating that the MAP was higher than the two minute column. It is believed that the blood pressure may have been measured inaccurately for the three minute mark.
While exercising, the skeletal muscles, lungs, and blood vessels all pump blood back to the heart creating a large increase in venous return. This can cause an increase in right atrial pressure, which results in an increase in heart rate (Bainbridge reflex). An increase in heart rate leads to an increase in cardiac output, which leads to an increase in MAP. When you are recovering from a workout, the PNS activates and attempts to bring the heart rate back to normal by releasing acetylcholine.
Cognitive Stress: The predicted values were fairly close to the observed values. Both MAP values of task B were exactly the same. The MAP values of task A were off by 1 mm Hg. The average pulse rates were off by 3-5 mm Hg.
When stressed, the baroreceptors in the carotid sinuses are inhabited which causes the medulla oblongata to activate the cardioacceleratory center (inhibiting the cardioinhibitory center) and vasomotor center. The cardioacceleratory center releases norepinephrine and epinephrine to increase heart rate, which increases cardiac output. The vasomotor center tells the vasomotor fibers to vasoconstrict, increasing resistance. An increase in resistance and increase in cardiac output would result in an increase in MAP.
8
References
Marieb, Elaine M. Human Anatomy and Physiology, 8th Edition. The Benjamin/ Cummings Publishing Company, Inc. (2010), pp. 705-706.
BIOL 204-506
Remi Ben-Davies
Dashaun Lee, Amanda Easter, and Lynne Baker
April 9th, 2015
1
Introduction:
Purpose: The purpose of this experiment was to determine how different variables may affect arterial pressure and pulse rate. Two subjects were used as models for the tests. The first two tests required the use of sphygmomanometers and stethoscopes to measure the arterial pressure and pulse rate. The last test required sphygmomanometers, plethysmographs, and the iworx system. Postural change was used as the variable in the first test to examine the changes of arterial pressure and pulse rate in subject 1. The next test included exercise as the variable. Subject 2 was required to have their resting blood pressure and pulse rate measured after performing an exercise. …show more content…
The last test used cognitive stress as a variable. Subject 1 had their blood pressure and pulse rate measured while performing the cognitive stress test.
Background: To be able to transport the ideal amount of blood to the appropriate organ systems, the rhythm of the heart is controlled by many factors. Blood pressure plays a significant role in controlling heart rate. Blood pressure, defined as the amount of force that presses up against the blood vessel walls, can be measured in millimeter of mercury (mm HG). Systolic pressure is the amount of force that presses up against the blood vessel walls during ventricular contraction (systole), and diastolic pressure is the same; however it occurs during ventricular relaxation (diastole). Blood pressure is measured as systolic pressure/diastolic pressure and pulse pressure is the difference between those two. Pulse pressure can be “felt as a throbbing pulsation in an artery during systole” (Marieb & Hoehn 702). You can use the blood
2
pressure and pulse pressure to find the mean arterial pressure (MAP). MAP can be calculated with this formula: diastolic pressure + (pulse pressure/3). Pulse pressure is the difference between the systolic and diastolic pressure.
.
Hypothesis: Both subjects will have an average baseline pulse rate and MAP for the first two tests. The average MAP is 93 mm HG (80 + 40/3). The average pulse rate for men is 70-72 beats per minute (bpm); and the average for women is 78-83. Subject 1’s predicted pulse rate was 80 bpm. And subject 2’s baseline was 71 bpm. Reclining for three minutes will decrease the pulse rate to 77 bpm and the MAP to 91 mm Hg (78 + 40/3) because the heart is not fighting against gravity to transport blood. Standing up immediately after reclining for three minutes will increase the pulse rate to 85 bpm and the MAP to 95 mm Hg (82 + 40/3). The heart works hard to supply blood to the muscles that are quickly helping the subject to stand up. After standing for three minutes, the subject’s pulse rate and MAP will go back to normal.
Immediately after exercising during the second test, subject 2’s pulse rate and MAP will increase to 100 bpm and 112 mm Hg (95 + 50/3) respectively. The minute after exercising would decrease the MAP to 99 mm Hg and the pulse rate to 95 bpm. The MAP and pulse rate would respectively decrease to 97 mm Hg and 92 bpm in the next minute; and then to 95 mm Hg and 88 bpm in the following minute.
3
Subject 1’s baseline would have an average MAP of 93 mm Hg during the cognitive stress test. During task A of the test, the subject’s MAP and pulse rate would respectively increase to 94 mm Hg and 84 bpm. The pulse rate and MAP would then respectively increase to 86 bpm and 96 mm Hg during task B.
Results:
Postural changes: Subject 1’s blood pressure and pulse rate were recorded at baseline, after three minutes of reclining, immediately upon standing, and after standing for three minutes.
4
Exercise: Subject 2 was required to perform the step up exercise for five consecutive minutes. The subject’s blood pressure and pulse rate was measured immediately after the workout, one minute after the workout, two minutes after the workout, and three minutes after the workout. Cognitive Stress Test: Subject 1 had their baseline blood pressure and average pulse rate measured with the iworx system. This test required the subject to spell 15 words forward (task A) and 15 other words backward (task B) while having their blood pressure and pulse rate measured.
5 Discussion: Generally, most of the predicted baseline values were all wrong. The predicted baseline values that were used were calculated to be average values. The normal blood pressure is 120/80, which is why the average MAP value was chosen to be 93 mm Hg (80 + 40/3). The pulse rates were all within the normal limits depending on whether the subject was male or
female. Postural Changes: For some reason, the subject’s baseline pulse rate was higher than any other posture pulse rate. The reason for that fact may come from a random error of someone measuring the heart rate incorrectly and losing count somewhere along the process. However, the baseline MAP seemed reasonably logical, being the lowest value. The subject’s
6
pulse rate and MAP after reclining for three minutes were roughly similar to the predicted values. The predicted values of the subject standing immediately after reclining for three minutes were far inaccurate. The subject’s values after standing for three minutes were also fairly wrong because they were not the predicted, normal values. It was believed that a person’s pulse rate and MAP would increase while a person is standing because the heart would be working twice as hard to pump blood to the extremities allowing the person to stand up; however that is not the case. While lying down, heart rate and blood pressure stay at ease because there is no gravity resistance. Standing up quickly would lead to a decrease in venous return because the heart would be fighting gravity to the pull blood towards it. A decrease in venous return results in a decrease in ending diastolic volume and stroke volume. Ending diastolic volume is the amount of blood filled in the ventricles during diastole, and stroke volume is the amount of blood ejected from those ventricles per heartbeat. A decrease in stroke volume results in the decrease of cardiac output, which is the amount of blood ejected from the ventricles per minute. Decreased cardiac output causes a decrease in MAP.
Exercise: Although the subject 2’s MAP and pulse rate increased dramatically after the workout, it did not match up with the predicted values. The subject’s pulse rate immediately after exercising was predicted to be 100 bpm; however the observed value was 144 bpm. The MAP also off by 12 mm Hg. The predicted values were all inaccurate, but the concept was generally the same as the observed values. There was a random error recorded for the three
7
minute column, stating that the MAP was higher than the two minute column. It is believed that the blood pressure may have been measured inaccurately for the three minute mark.
While exercising, the skeletal muscles, lungs, and blood vessels all pump blood back to the heart creating a large increase in venous return. This can cause an increase in right atrial pressure, which results in an increase in heart rate (Bainbridge reflex). An increase in heart rate leads to an increase in cardiac output, which leads to an increase in MAP. When you are recovering from a workout, the PNS activates and attempts to bring the heart rate back to normal by releasing acetylcholine.
Cognitive Stress: The predicted values were fairly close to the observed values. Both MAP values of task B were exactly the same. The MAP values of task A were off by 1 mm Hg. The average pulse rates were off by 3-5 mm Hg.
When stressed, the baroreceptors in the carotid sinuses are inhabited which causes the medulla oblongata to activate the cardioacceleratory center (inhibiting the cardioinhibitory center) and vasomotor center. The cardioacceleratory center releases norepinephrine and epinephrine to increase heart rate, which increases cardiac output. The vasomotor center tells the vasomotor fibers to vasoconstrict, increasing resistance. An increase in resistance and increase in cardiac output would result in an increase in MAP.
8
References
Marieb, Elaine M. Human Anatomy and Physiology, 8th Edition. The Benjamin/ Cummings Publishing Company, Inc. (2010), pp. 705-706.