Ice Experiment

DATA

Table 1–Baseline Blood Pressure

Systolic pressure (mm Hg)

Diastolic pressure (mm Hg) Mean arterial pressure (mm Hg)

118 mm Hg 79 mm Hg 97 mm Hg

Table 2–Blood Pressure Response to Cold

Systolic pressure (mm Hg)

Diastolic pressure (mm Hg)

Mean arterial pressure (mm Hg)

130 mm Hg 80 mm Hg 107 mm Hg

Table 3

Condition Heart rate (bpm)

Time (s)

Resting heart rate 86 BPM 25.2 sec

Maximum heart rate 106 BPM 38 sec

Rebound heart rate 94 BPM 34.3 sec

Data Analysis

1. Describe the trends that occurred in the systolic pressure, diastolic pressure, mean

arterial pressure, and heart rate with cold stimulus. How might these responses be useful in

a “fight or flight” situation?

When your heart beats, it contracts and pushes blood through the arteries to the rest of your body. This

force creates pressure on the arteries. This is called systolic blood pressure. The diastolic blood pressure

number 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 one

heartbeat. (4) When the foot was immersed into the water, the new environment made the nerves in the

foot send a signal to the central nervous system, telling it that a new and uncomfortable stimulus was

introduced that may stunt or get in the way of homeostasis for that particular part of the body. The CNS

sent signals to the brain, telling it to remove the foot from the cold water. The brain increased blood flow

to the limbs, thus increasing the diastolic, systolic, and mean arterial pressure in the body in order to

increase the amount of oxygen delivery to allow the muscles to move quicker and react faster than when

in 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 the

systolic and diastolic pressures for the class and calculate the average for each. Rate the

class average blood pressure using the follow scale:

Blood Pressure Category

140/90 or higher High

120–139/80–89 Pre-hypertension

119/79 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 pressure

for 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 the

physiologic 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 sec

Fight-or-Flight reaction is a set of physiological changes, such as increases in heart rate, arterial blood

pressure, and blood glucose, initiated by the sympathetic nervous system to mobilize body systems in

response 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 arterial

pressure 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 increased

by 20 BPM in 38 seconds, so for 30 seconds the subconscious and conscious mind were both at work in

controlling the body’s reaction to the cold stimulus. When the stimulus was removed, it took 34.3 seconds

for 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 the

minimum heart rate value? How would you explain the heart rate variations seen in the remainder of the

experiment?

-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 to

increases its rate to accommodate the body. After she put her foot in the ice water, her body reacted in a

panicked manner and her heart rate shot up to reach the maximum rate. After taking her foot out of the

water, her heart rate began to drop and return to its normal rate, which was only a few BPM more than

the minimum/resting heart rate.

5. How long after the maximum heart rate did it take to arrive at your rebound heart rate? What can you

say about the relative speed of physiologic response to a stimulus vs. the speed of mechanisms that are

designed to maintain homeostasis?

-It took her heart 34.3 seconds to return to the rebound heart rate after reaching its maximum, while it

took her heart 38 seconds to reach its maximum initially. Our data suggests that the heart reacts to a

stimulus slower than it reacts in order to maintain homeostasis, however we expected the heart to react

much faster when the foot was initially submerged in the ice water than when the heart was attempting to

achieve its rebound rate.

6. If the heart rate is too slow there is inadequate blood pressure to maintain perfusion to the brain. This

can lead to loss of consciousness (fainting). Keeping in mind the autonomic nervous system responses

that you observed in this experiment, explain the sequence of events that results in a severely frightened

person fainting.

-Fainting due to being startled or frightened is known as Neurocardiogenic syncope and is caused by a

short-term malfunction of the autonomic nervous system. The body is in such a frightened state that the

ANS begins to lower the blood pressure and heart rate, causing the brain’s supply of oxygen to be

temporarily interrupted. The brain uses fainting as a survival mechanism in response to a drop in oxygen

levels to shut down all the non-vital parts of the body so that resources can be focused on the vital parts

of the body. To do this, the brain increases the breathing rate and heart rate to direct blood to the brain at

the expense of other parts of the body. This combination of hypertension and low blood pressure in the

body can cause the body to shut down, or faint.

Exercise experiment

DATA

Table 1–Baseline Blood Pressure

Systolic pressure (mm Hg)

Diastolic pressure (mm Hg)

Mean arterial pressure (mm Hg)

Pulse (bpm)

111 67 81 89

Table 2–Blood Pressure After Exercise

Systolic pressure (mm Hg)

Diastolic pressure (mm Hg)

Mean arterial pressure (mm Hg)

Pulse (bpm)

125 85 101 71

Table 3–Heart Rate

Condition

Resting heart rate (bpm) 68

Maximum heart rate (bpm) 108.7

Recovery time (s) 1 min 9 sec

DATA ANALYSIS

1. Describe the trends that occurred in the systolic pressure, diastolic pressure, mean

arterial pressure and pulse with exercise. Assume that the stroke volume increased from 75

mL/beat to 100 mL/beat. Use this information and the change in pulse with exercise to

calculate the change in cardiac output (stroke volume × heart rate) that occurred per

minute.

The systolic, diastolic, and mean arterial pressure increases during running along with the

pulse rate. The systolic, diastolic and mean arterial pressures, and pulse rate return to

normal a little over a minute because our person is in soccer and they have a faster

recovery time than someone who doesn’t exercise or is active. The cardio output before

running 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 active

contraction of the ventricles) and diastolic pressure (the pressure that is maintained even

while the left ventricle is relaxing). Describe the change in pulse pressure seen with

exercise. 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 left

ventricle ejects blood which causes aorta pressure. The change is caused by the stroke

volume of the ventricle. (6)

3. A change in pulse pressure can be seen in a variety of medical conditions. What would

you 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, so

atherosclerosis hinders the stroke volume. (7)

(b) A damaged aortic valve does not seal properly and allows blood to flow back into the

ventricle during diastole.

The pulse pressure increases because the aortic valve is leaky and the systolic pressure

increases 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 above

resting rate with exercise? What percent increase was this?

Our resting heart rate was 68. After/during exercise increased about 40.7 beats. And the

percent increase is 63%.

5. How does your/the subject’s maximum heart rate compare with other students in your

group/class? Is this what you expected?

It is average compared to the other results. Our resting heart rate was slightly higher than

the rest of the class but during exercise, the heart rate increases to supply the body with

enough oxygenated blood.

6. Recovery time has been shown to correlate with degree of physical fitness. How does

your/the subject’s recovery rate compare to that of your classmates? Is this what you

expected?

Our recovery time was shorter compared to our classmates because the person we tested

with was a fit athlete. This is what we expected because a person that exercises daily has a

shorter recovery time than someone that does not exercise often.

7. Congestive heart failure is a condition in which the strength of contraction with each beat

may be significantly reduced. For example, the ventricle may pump only half the usual

volume of blood with each beat. Would you expect a person with congestive heart failure to

have 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 much

faster when the person is exercising

8. Medications are available which can slow the heart or speed it up. If a patient complains

of feeling poorly and has a heart rate of 120 beats per minute, should you administer a

medicine to slow the rate?

Yes, because the average heart rate is 70-75 beats per minute under resting conditions.

Works Cited

1. Thibodeau, Gary, and Kevin Pattron. Anthony’s Textbook of Anatomy and Physiology. St.

Louis Missouri, Mosby 2003.

2. Nordqvist, Christian. "What Is Fainting (Syncope)? What Causes Fainting?." Medical News

Today. N.p., 17 Mar 2010. Web. 24 Jan 2013

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<http://www.webmd.com/hypertension-high-blood-pressure/guide/diastolic-and-systolic-blood-

pressure-know-your-numbers>.

4 Saunders, . "Mean Arterial Pressure." Dorland's Medical Dictionary For Health Consumers.

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. Houghton Mifflin

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." Cardiovascular Physiology

Concept. N.p., 29 Mar 2007. Web. 25 Jan 2013. <http://www.cvphysiology.com/Blood

7. . "Patient Education." Cardiovascular Medicine. University of Southern California Keck School

of Medicine. Web. 28 Jan 2013. <http://www.usccardiology.org/pg-