Ice ExperimentDATATable 1–Baseline Blood Pressure Systolic pressure Diastolic pressure (mm Hg) Mean arterial pressure (mm Hg) (mm Hg) 118 mm Hg 79 mm Hg 97 mm Hg Table 2–Blood Pressure Response to Cold Systolic pressure Diastolic pressure (mm Mean arterial pressure (mm (mm Hg) Hg) Hg) 130 mm Hg 80 mm Hg 107 mm Hg Table 3 Condition Heart rate Time (bpm) (s) Resting heart rate 86 BPM 25.2 sec Maximum heart rate 106 BPM 38 sec Rebound heart rate 94 BPM 34.3 secData Analysis1. Describe the trends that occurred in the systolic pressure, diastolic pressure, meanarterial pressure, and heart rate with cold stimulus. How might these responses be useful ina “fight or flight” situation?When your heart beats, it contracts and pushes blood through the arteries to the rest of your body. Thisforce creates pressure on the arteries. This is called systolic blood pressure. The diastolic blood pressurenumber or the bottom number indicates the pressure in the arteries when the heart rests between beats.(3) Mean arterial pressure is the average pressure within an artery over a complete cycle of oneheartbeat. (4) When the foot was immersed into the water, the new environment made the nerves in thefoot send a signal to the central nervous system, telling it that a new and uncomfortable stimulus wasintroduced that may stunt or get in the way of homeostasis for that particular part of the body. The CNSsent signals to the brain, telling it to remove the foot from the cold water. The brain increased blood flowto the limbs, thus increasing the diastolic, systolic, and mean arterial pressure in the body in order toincrease the amount of oxygen delivery to allow the muscles to move quicker and react faster than whenin a homeostatic state. This same reaction occurs during Fight-or-Flight reactions.2. As a vital sign, blood pressure is an indicator of general health. A high blood pressure
(140/90 or higher) increases the risk of cardiovascular disease and strokes. Collect thesystolic and diastolic pressures for the class and calculate the average for each. Rate theclass average blood pressure using the follow scale:Blood Pressure Category140/90 or higher High120–139/80–89 Pre-hypertension119/79 or below Normal Systolic Pressure Diastolic Pressure Group 1- 131 Group 1- 90 Group 2- 118 Group 2- 79 Group3- 128 Group 3- 86 Group 4- 116 Group 4- 79 Group 5- 119 Group 5- 83 (131+118+128+116+119= 612/5= 122.4) (90+79+86+79+83= 417/5= 83.4) Average BP is (122/83)The average diastolic blood pressure for the class is . the average systolic blood pressurefor the class is. Therefor the average blood pressure for the class is / which falls into the__Pre-Hypertension_ category.3. How long after immersion did your heart rate reach its maximum value? Explain thephysiologic mechanism that led to this change in heart rate. Resting heart rate 86 BPM 25.2 sec Maximum heart rate 106 BPM 38 sec Rebound heart rate 94 BPM 34.3 secFight-or-Flight reaction is a set of physiological changes, such as increases in heart rate, arterial bloodpressure, and blood glucose, initiated by the sympathetic nervous system to mobilize body systems inresponse to stress.(5) It took the heart 38 seconds to reach it maximum number of beats per minute(BPM). During this time frame, the heart was constantly increasing blood pressure, and mean arterialpressure in order to increase reaction time to remove the foot from the water, as explained in question 1.This entire reaction happens subconsciously, meaning the mind is not aware of what is occurring.However, the foot was not removed, which is a conscious reaction by the body. The heart rate increasedby 20 BPM in 38 seconds, so for 30 seconds the subconscious and conscious mind were both at work incontrolling the body’s reaction to the cold stimulus. When the stimulus was removed, it took 34.3 secondsfor the heart to return to a consistent 94 BPM. The slowing of the heart rate was all subconscious.4. Describe the changes in heart rate that occurred after the maximum value. How can you explain theminimum heart rate value? How would you explain the heart rate variations seen in the remainder of theexperiment?-Right after her heart rate reached its maximum value, it drastically decreased to almost the resting heart
rate. The minimum heart rate was when the subject was resting because the heart had not yet needed toincreases its rate to accommodate the body. After she put her foot in the ice water, her body reacted in apanicked manner and her heart rate shot up to reach the maximum rate. After taking her foot out of thewater, her heart rate began to drop and return to its normal rate, which was only a few BPM more thanthe minimum/resting heart rate.5. How long after the maximum heart rate did it take to arrive at your rebound heart rate? What can yousay about the relative speed of physiologic response to a stimulus vs. the speed of mechanisms that aredesigned to maintain homeostasis?-It took her heart 34.3 seconds to return to the rebound heart rate after reaching its maximum, while ittook her heart 38 seconds to reach its maximum initially. Our data suggests that the heart reacts to astimulus slower than it reacts in order to maintain homeostasis, however we expected the heart to reactmuch faster when the foot was initially submerged in the ice water than when the heart was attempting toachieve its rebound rate.6. If the heart rate is too slow there is inadequate blood pressure to maintain perfusion to the brain. Thiscan lead to loss of consciousness (fainting). Keeping in mind the autonomic nervous system responsesthat you observed in this experiment, explain the sequence of events that results in a severely frightenedperson fainting.-Fainting due to being startled or frightened is known as Neurocardiogenic syncope and is caused by ashort-term malfunction of the autonomic nervous system. The body is in such a frightened state that theANS begins to lower the blood pressure and heart rate, causing the brain’s supply of oxygen to betemporarily interrupted. The brain uses fainting as a survival mechanism in response to a drop in oxygenlevels to shut down all the non-vital parts of the body so that resources can be focused on the vital partsof the body. To do this, the brain increases the breathing rate and heart rate to direct blood to the brain atthe expense of other parts of the body. This combination of hypertension and low blood pressure in thebody can cause the body to shut down, or faint.Exercise experimentDATATable 1–Baseline Blood Pressure Systolic pressure Diastolic pressure Mean arterial pressure Pulse (mm Hg) (mm Hg) (mm Hg) (bpm) 111 67 81 89Table 2–Blood Pressure After Exercise Systolic pressure Diastolic pressure Mean arterial pressure Pulse (mm Hg) (mm Hg) (mm Hg) (bpm)
125 85 101 71 Table 3–Heart Rate ConditionResting heart rate (bpm) 68Maximum heart rate (bpm) 108.7Recovery time (s) 1 min 9 secDATA ANALYSIS1. Describe the trends that occurred in the systolic pressure, diastolic pressure, meanarterial pressure and pulse with exercise. Assume that the stroke volume increased from 75mL/beat to 100 mL/beat. Use this information and the change in pulse with exercise tocalculate the change in cardiac output (stroke volume × heart rate) that occurred perminute.The systolic, diastolic, and mean arterial pressure increases during running along with thepulse rate. The systolic, diastolic and mean arterial pressures, and pulse rate return tonormal a little over a minute because our person is in soccer and they have a fasterrecovery time than someone who doesn’t exercise or is active. The cardio output beforerunning in pace is 2225 per minute and 1,775 per minute after running.2. Pulse pressure is the difference between systolic pressure (peak pressure during activecontraction of the ventricles) and diastolic pressure (the pressure that is maintained evenwhile the left ventricle is relaxing). Describe the change in pulse pressure seen withexercise. Which component of the blood pressure is most responsible for this change?The pulse pressure in the beginning of the exercise is less than after running. The leftventricle ejects blood which causes aorta pressure. The change is caused by the strokevolume of the ventricle. (6)3. A change in pulse pressure can be seen in a variety of medical conditions. What wouldyou expect to happen to the pulse pressure in the following examples?(a) In atherosclerosis there is a hardening of the arterial walls.It blocks the flow the blood in which decreases the amount of blood the left ventricle ejects,which lowers the stroke volume. The stroke volume determines the pulse pressure, soatherosclerosis hinders the stroke volume. (7)(b) A damaged aortic valve does not seal properly and allows blood to flow back into theventricle during diastole.The pulse pressure increases because the aortic valve is leaky and the systolic pressureincreases as the diastolic pressure decreases. (7)4. Normal resting heart rates range from 55−100 beats per minute. What was your/the
subject’s resting heart rate? How much did your/the subject’s heart rate increase aboveresting rate with exercise? What percent increase was this?5. How does your/the subject’s maximum heart rate compare with other students in yourgroup/class? Is this what you expected?It is average compared to the other results. Our resting heart rate was slightly higher thanthe rest of the class but during exercise, the heart rate increases to supply the body withenough oxygenated blood.6. Recovery time has been shown to correlate with degree of physical fitness. How doesyour/the subject’s recovery rate compare to that of your classmates? Is this what youexpected?Our recovery time was shorter compared to our classmates because the person we testedwith was a fit athlete. This is what we expected because a person that exercises daily has ashorter recovery time than someone that does not exercise often.7. Congestive heart failure is a condition in which the strength of contraction with each beatmay be significantly reduced. For example, the ventricle may pump only half the usualvolume of blood with each beat. Would you expect a person with congestive heart failure tohave a faster or slower heart rate at rest? With exercise?I would expect that the person’s heart rate would be faster than normal at rest and muchfaster when the person is exercising8. Medications are available which can slow the heart or speed it up. If a patient complainsof feeling poorly and has a heart rate of 120 beats per minute, should you administer amedicine to slow the rate?Yes, because the average heart rate is 70-75 beats per minute under resting conditions.
Works Cited1. Thibodeau, Gary, and Kevin Pattron. Anthony’s Textbook of Anatomy andPhysiology. St. Louis Missouri, Mosby 2003.2. Nordqvist, Christian. "What Is Fainting (Syncope)? What Causes Fainting?." MedicalNews Today. N.p., 17 Mar 2010. Web. 24 Jan 20133."Know Your Blood Pressure Numbers." Web MD. WebMD, LLC. Web. 24 Jan 2013.<http://www.webmd.com/hypertension-high-blood-pressure/guide/diastolic-and-systolic-blood-pressure-know-your-numbers>.4 Saunders, . "Mean Arterial Pressure." Dorlands Medical Dictionary For HealthConsumers. Elsevier, Inc., n.d. Web. 25 Jan 2013. <http://medical-dictionary.thefreedictionary.com/mean arterial pressure>.5.”Fight-Or-Flight Reaction." The American Heritage® Medical Dictionary. HoughtonMifflin Company, n.d. Web. 25 Jan 2013. <http://medical-dictionary.thefreedictionary.com/fight-or-flight reaction>.6. Klabunde, Richard E.. "Arterial and Aorta Pulse Pressure." CardiovascularPhysiology Concept. N.p., 29 Mar 2007. Web. 25 Jan 2013.<http://www.cvphysiology.com/Blood7. . "Patient Education." Cardiovascular Medicine. University of Southern CaliforniaKeck School of Medicine. Web. 28 Jan 2013. <http://www.usccardiology.org/pg-