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					Name_________________________                                                Period_____

             AP BIOLOGY LAB 10: PHYSIOLOGY OF THE CIRCULATORY SYSTEM

BACKGROUND
        In order for a cell to survive, it must be in a favorable environment that is rich in nutrients and
oxygen for respiration, with a low concentration of waste produced by cellular metabolism. In lower
animals, such as sponges, this is archived entirely by water flowing across body membranes. More
advanced body systems, such as are found in humans, require a more complex system to transport fluids
and maintain a favorable extracellular environment.
        Like all vertebrates, humans have a closed circulatory system, which consists of a network of blood
vessels and muscular, pumping heart that pushes blood through arteries and veins. This network of blood
vessels is divided into two distinct circuits: the systemic and pulmonary circulatory systems. Pulmonary
circulation carries oxygen-depleted blood to the lungs and returns oxygen-rich blood to the heart. The
systemic circulation then distributes this oxygenated blood to the tissues of the body.
        When the metabolic rate of tissues increases, as it does during exercise, the demand for oxygen
and nutrients increases along with it. To satisfy this increase in demand, the circulatory system adapts in a
number of ways: heart rate, arterial pressure, and breathing rate increase, and blood flow to muscle tissue
increases while decreasing in other tissues.
        In order for the blood pumped by the heart to reach the cells of body tissues, there must be
considerable pressure in the arteries and arterioles. This pressure is determined by the rate of blood flow
through, and the resistance in, the arterioles. Blood pressure is at its highest when the heart in actively
contracting; this is referred to as systolic pressure. Diastolic blood pressure, lower than the systolic value,
occurs when the heart is at rest. A common, “normal” blood pressure might be 120/70, which means that
the pressure during systole is 120 mm Hg, and the pressure during diastole is 70 mm Hg. The range of
normal blood pressure is dependent on heredity, sex, age, and environmental factors.
        Blood pressure is measured using a
sphygmomanometer and a stethoscope. By applying pressure                                                    to
the blood vessels of the upper arm with the cuff of the
sphygmomanometer, and listening for the sounds of Korotkoff
(Korotkoff sounds) with the stethoscope, the systolic and
diastolic pressures can be determined. The sounds of the
Korotkoff, named for the man who discovered them, occur
when the arm cuff if the sphygmomanometer is pumped high
enough to restrict blood flow to the artery. As the cuff valve is
released, the pressure eventually reaches a point equal to
systolic pressure. When this happens, blood is forced through the compressed artery and the vibrations of
the artery walls become audible with the stethoscope as a distinct tapping noise. As the pressure continues
to lessen, the sounds change. Five distinct phrases (Figure 1) occur, with the final phrase being a
disappearance of sound altogether. This is equivalent to the diastolic pressure. The sounds of Korotkoff
usually become audible around 120 mm Hg. Systolic pressure can be noted when the sounds begin, and
diastolic pressure when the sounds stop.

Figure 1
Phase 1     Tapping (Systolic)
Phase 2     Murmur with tapping (10-15mm lower)
Phase 3     Tapping only
Phase 4     Muffling
Phase 5     Disappearance of sounds (diastolic)

        Heart rate, and its change under different conditions, is a measurement of and individual’s physical
fitness. Exercise makes the heart more efficient, able to pump more blood with each contraction. The
amount of blood the heart pumps with each beat is referred to as stroke volume. A person in good physical
shape will have a higher stroke volume and a lower resting heart rate.
        Maximum heart rate, a constant for a particular age group, is also an indicator of fitness. Individuals
who are not in very good shape will reach the maximum heart rate at a lower level of exertion than a
person of the same age who exercises regularly. Likewise, well conditioned people will show a smaller
increase un cardiac rate with exercise, and they will also return to their resting heart rate much more
quickly than people who are not in good shape.

   OBJECTIVES
      Measure pulse rate and, using a sphygmomanometer, blood pressure
      Demonstrate the effect of body position on both blood pressure and pulse rate
      Examine the effects of exercise on heart rate
      Apply heart rate and blood pressure data to determine an individual’s level of fitness
      Define the value of Q10 and demonstrate it using Daphnia
   MATERIALS
         Stereomicroscope
         Blood pressure kit
         Chair
         Stopwatch
PROCEDURES
A) MEASURING BLOOD PRESSURE
     1. Have one member of the lab group sit down in a chair and roll up his or her shirt sleeve. Be sure
        the shirt sleeve is not constricting on the arm and interfering with the flow of blood through the
        artery. Attach the sphygmomanometer cuff to his or her upper arm at heart level. Close the
        valve on the sphygmomanometer by turning it clockwise.
     2. Place the stethoscope in the well of the subject’s elbow. Pump the cuff to a pressure that is
        safely higher than the blood pressure of the subject. A good starting point is usually 200 mm Hg.
     3. Slowly open the valve to allow the cuff pressure to fall slowly. Open the valve until the drop in
        pressure is between 125 and 20 mm Hg over 10 seconds. Listen for a pulse.
     4. Note the pressure on the gauge when you first hear sounds of Korotkoff. This is the pressure at
        which blood is first able to pass through the artery during systole, representing systolic
        pressure. You will hear these sounds between the systolic and diastolic blood pressures.
        Continue listening and note the pressure at which the sounds disappear. This represents the
        diastolic pressure. Record both numbers in Table 1 in the Analysis section of the lab.
     5. Take the subject’s blood pressure two more times. Record the results in Table 1. Average the
        blood pressure from the three trials and compare your results with those in figure 2.
     6. Repeat the procedure with another student from the lab group as the subject.

            Table 2: AVERAGE BLOOD PRESSURE
                              DATA
            Systolic              Diastolic                B) PHYSICAL FITNESS TEST: STANDING
Age (yrs)   Men      Women        Men      Women               VS. RESTING SYSTOLIC BLOOD
10          103      103          69       70                  PRESSURE
12          106      106          71       72                       1. Have one member of the lab group
14          110      110          73       74                          lie down on a lab bench or cot and
16          118      116          73       72                          rest for five minutes.
18          120      116          74       72                       2. After five minutes have elapsed,
20-24       123      116          76       72                          take the subject’s blood pressure
25-29       125      117          78       74                          while he or she remains lying down.
                                                                       Record the data in Table 2 in the
30-34       126      120          79       75
                                                                       Analysis section.
35-39       127      124          80       78
                                                                    3. Have the subject continue to lie
40-44       129      127          81       80
                                                                       down on the lab bench or cot for two
45-49       130      131          82       82
                                                                       more minutes
50-54       135      137          83       84                       4. After the two minutes have elapsed,
55-59       138      139          84       84                          have the subject stand up. Take
60-64       142      144          85       85                          another blood pressure
65-69       143      154          83       85                          measurement immediately. Record
70-74       145      159          82       85                          the data in Table 2.
       5. Subtract the standing systolic blood pressure measurement from the resting systolic pressure
          measurement; record the data in Table 2.
       6. Use the chart below to determine how many points the subject receives for this part of the test
          and record the points in Table 3 in the Analysis section.
CHANGE IN BLOOD PRESSURE
Pressure (mm Hg)           Points
Increase of 8 or more      3
Increase of 2 to 7         2
No Change (+1 to -1)       1
Decrease of 2 to 5         0
Decrease of 6 or more      -1


C) STANDING HEART RATE

       1. Have the subject stand for two minutes.
       2. Take the subject’s radial artery pulse. Count the number of beats for 30 seconds and multiply
           the number by two to obtain the number of beats per minute. Record the results in Table 3 in
           the Analysis section.
       3. Use the chart below to determine how many points the subject receives for this part of the test
           and record the points in Table 3.
STANDING HEART RATE
Pulse Rate      Points
 (Beats/Min)
60 to 70        3
71 to 80        3
81 to 90        2
91 to 100       1
101 to 110      1
111 to 120      0
121 to 130      0
131 to 140      -1

D) RESTING HEART RATE
     1. Have the subject lie down on a lab bench or cot for five minutes.
     2. After five minutes have elapsed, take the subject’s pulse. Record the results in Table 3 in the
        Analysis section.
     3. Use the chart below to determine how many points the subject receives for this part of the test
        and record the points in Table 3.

RESTING HEART RATE
Pulse Rate   Points
 (Beats/Min)
50 to 60     3
61 to 70     3
71 to 80     2
81 to 90     1
91 to 100    0
101 to 110   -1



E) BARORECEPTOR REFLEC TEST
     1. After recording the results from the previous test, have the subject stand up quickly. Take the
        subject’s pulse immediately.
     2. Subtract the Resting Heart Rate from the Baroreceptoror Reflex Heart Rate. Record the results
        in Table 3 in the Analysis section.
     3. Use the chart below to determine how many points the subject receives for this part of the test
        and record the points in Table 3.


                   Difference in Heart Rates
                                    Heart Rate Increase
 Resting Heart Rate        0-    11-18   19-26    27-34       35-43
         (b/m)             10
50 to 60                   3       3         2        1         0
61 to 70                   3       2         1        0         -1
71 to 80                   3       2         0        -1        -2
81 to 90                   2       1         -1       -2        -3
91 to 100                  1       0         -2       -3        -3
101 to 110                 0       -1        -3       -3        -3

F) ENDURANCE TEST
     1. Obtain a wooden box or stool approximately 18” high. Have the subject step up by placing one
        foot on the box, bringing the other foot up next to it, and then returning the first foot to the floor.
        The subject should repeat this several times over a period of approximately 15 seconds.
     2. After the subject has completed the step exercise, immediately take his or her pulse for a period
        of 15 seconds and record the result in Table 4 in the Analysis section.
     3. Take the subject’s pulse for another 15 seconds and record the result in Table 4.
     4. Continue to take the subject’s pulse ever 30 seconds for up to 120 seconds after the exercise.
        Record the data in Table 4 in the Analysis section.
     5. Calculate the number of beats per minute by multiplying your results in Table 4 by the BPM
        (beats per minute) factor.
     6. Determine the amount of time it took for the subject’s heart rate to return to normal. Use the
        subject’s Standing Heart Rates the normal heart rate. Use the chart below to determine how
        many points the subject receives for this part of the test and record the points in Table 3.
     7. Subtract the Standing Heart Rate from the rate immediately after exercise in the Endurance
        Test. If the difference is greater than 10, subtract one point from each recovery interval. Use the
        chart below to determine how many points the subject receives for this part of the test and
        record the points in Table 3.

Recovery Interval
Seconds    Points
0 to 30    4
31 to 60   3
61 to 90   2
91 to 120  1
121+       1

Heart Rate After Exercise
Standing Heart Rate   0-10       11-20    21-30    31-40     41+
60 to 70              3          3        2        1         0
71 to 80              3          2        1        0         -1
81 to 90              3          2        1        -1        -2
91 to 100             2          1        0        -2        -3

Key Concepts I: Blood Pressure and Pulse
http://www.phschool.com/science/biology_place/labbench/lab10/concepts1.html
Table 1
Student 1
Name ____________________________
Blood Pressure    Systolic  Diastolic
Trial #1
Trial #2
Trial #3
Average
                                                   Student 2
                                                   Name ____________________________
Table 2: Standing vs. Resting Blood                Blood Pressure  Systolic Diastolic            Pressure
Position             Systolic   Diastolic          Trial #1
Lying down 5 min                                   Trial #2
Lying to standing                                  Trial #3
Change                                             Average

Table 3: Fitness Points
Activity                                  Result         Fitness Points
Change in Blood Pressure
Standing Heart Rate
Resting Heart Rate
Baroreceptor Reflex
Heart Rate Recovery after exercise
Heart Rate Increase after exercise
Total Points

Table 4: Heart Rate after Exercise
Interval       # of Beats   BPM Factor        Heart Rate
0-15 sec.                        x4=
16-30 sec.                       x4=
31-60 sec.                       x4=
61-90 sec.                       x4=
91-120 sec.                      x4=

Total Score    Cardiovascular Fitness
17 to 18       Excellent
14 to 16       Good
8 to 13        Fair
7 or less      Poor

SELF QUIZ:
   1. Which of the following has the LEAST effect on blood pressure in a young adult?

   2. An individual's blood pressure is reported as 110/50. Which of the following is correct?

   3. Which of the test results would be most typical of a well-conditioned athlete?


   4. Which of the test results indicate a person with the lowest level of fitness?


ANALYSIS QUESTIONS:

   1. Why does increased physical activity raise heart rate?

   2. Why is heart rate lower in an individual who does aerobic exercise regularly?

   3. Why do some people feel faint when they go quickly from lying down to standing?

   4. How and why does heart rate change with body position?

   5. Is the max heart rate of a fit and unfit teenager the same? Explain in detail.

   6. From your study of the circulatory system, how would you describe a "fit" individual?
DAPHNIA HEART RATE LAB
http://www.phschool.com/science/biology_place/labbench/lab10/concepts2.html

KEY CONCEPTS II: TEMPERATURE AND METABOLIC ACTIVITY

                                      Unlike mammals, the rate of metabolism and physiological mechanisms
                             of “cold-blooded”, or ectothermic, animals is dependent on the temperature of
                             the organism’s environment. Although most biochemical reactions taking place
                             in their bodies occur faster at higher temperatures, the effect is quite noticeable
                             as the metabolic rate, as well as rate of activity, of animals such as reptile’s
                             increases dramatically between 5° and 35°C. This increase in metabolism is
                             expressed in terms of the value”Q10”. Q10 is defined as the ratio of the metabolic
                             rate of an organism at one temperature as compared to the metabolic rate at a
                             temperature 10°C lower.
                                      An ideal organism for study of an ectotherm’s rate of metabolism is the
                             water flea, Daphnia magna, due to its varied habitats and easily studied
anatomy. Although the complex muscular system obscures some of the Daphnia’s smaller anatomical
features, the essential parts of most organ systems can be easily distinguished. The simple football shaped
heart is readily visible behind the head of the dorsal side of the
animal. Its heart rate is variable with water temperature, making it
easy to alter the Daphnia’s heart rate and observe the changes.
        In the Cellular Respiration laboratory, you experimented with
peas and saw how the rate of oxygen consumption during cellular
respiration varied with temperature. In that lab, you experimented
with peas to see how the rate of oxygen consumption during cellular
respiration increased with temperature.
        In animals, an increase in cellular respiration triggers
homeostatic mechanisms that increase both breathing and heart
rate, resulting in more oxygen being available to cells.
In the second part of this lab, you will study the relationship between temperature and metabolic activity in
an ectothermic animal. An ectotherm is an animal whose body temperature is much the same as its
surroundings, such as a frog, a cricket, or a snake.
        Thermoregulation is the maintenance of internal temperatures within a range that allows cells to
function. It may involve both physiological and behavioral adaptations. For example, humans
thermoregulate by sweating and shivering, dogs by panting, and snakes by basking on sunny rocks.
        Because ectotherms' temperature remains close to that of their environment, they face special
challenges in thermoregulation. Ectotherms exhibit a variety of behaviors that allow them to gain or lose
heat. Examples include basking in the sun and burrowing in mud. Because metabolic rate increases with
increasing temperature, ectotherms do not become active until their body has absorbed heat and warmed
up. This accounts for the sluggish early morning behavior of ectotherms such as snakes.
Measuring Temperature and Metabolic Rate
The rate of metabolism in ectothermic animals increases as the environmental temperature increases. This
rise occurs because the reactants in the cell have greater thermal energy, and many cellular enzymes are
more active as temperature increases. This effect is noticeable in a range from approximately 5°C to 35°C;
at temperatures much higher than this, enzymes become denatured. The graph above illustrates the effect
of increased temperature on metabolic rate in an aquatic ectotherm, Daphnia magna (water "flea").
        The relationship between temperature and metabolic rate is often measured as Q10. If the metabolic
rate doubles with a 10°C increase in temperature, then Q10 = 2.
        Q10= rate at the higher temperate divided by the rate at the lower temperature
                                             Q10= [K2/K1]
ANALYSIS
 Temperature       Heart Rate ( beats/10 sec)          Heart Rate ( beats/minutes)
 10°C
 20°C
 30°C

1. Create a graph of Heart Rate vs. Temp




   Continue with the tutorial and then take the self test
2. What is the relationship between metabolic rate and a 10°C increase in temperature?



3. Which of the following organisms would show the greatest fluctuation in body temperature hour by
   hour?




4. What is the relationship between metabolic rate and body temperature in Daphnia?




5. If the heart rate experiment was performed on an endothermic organism, what result would you expect?




6. If Q10 = 2, then an enzymatic reaction that takes place at a given rate at 5°C would take place
   approximately how many times faster at 25°C?
7. Create a Venn diagram that shows the similarities an difference between endotherms and ectotherms

				
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