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Unit 03 - Student book
9/25/03
1:00 PM
Page 102
9. The risk factors that are associated with cardiovascular disease include smoking, physical inactivity, high blood cholesterol, high blood pressure, obesity, poor eating habits, stress, diabetes, and genetics.
Making Connections
10. Answers will vary. A number of factors, individually or in combination, can lead to cardiovascular disease, such as
smoking, diets high in saturated fats, physical inactivity, stress, a family history of heart disease, and obesity. Below
is a list of ways in which you can improve your cardiovascular health:
• Eat a wider variety of foods, especially fruits and vegetables, and choose lower-fat foods more often.
• As little as 60 min a day of accumulated physical activity will help keep your heart in shape.
• If you smoke, quit. Now!
• Diabetes and high cholesterol are major contributors to cardiovascular disease. These conditions usually have
genetic links.
Exploring
11. Student answers will vary.
Disease
Phlebitis
Cause(s)
Phlebitis is a condition where the walls of one or more veins are inflamed. This inflammation may
be caused by infection or injury, or by the formation of clots and the pooling of blood in the veins.
Phlebitis can occur in any vein in the body but occurs most commonly in the leg veins.
Symptoms
The most common symptom is pain and tenderness in the area of the inflammation. If the superficial veins are affected there might also be redness and itchiness in the tissue around the vein(s).
Treatments
Treatments usually include anti-inflammatory drugs, application of heat, and wearing elastic
compression stockings; also rest and elevation of the legs during the period of inflammation.
12. The first wave on the electrocardiogram (ECG), referred to as a P wave, monitors the contraction of the atria. The
larger spike, referred to as the QRS wave, records the contraction of the ventricles. A final T wave signals that the
ventricles have recovered from the contraction.
3.11 INVESTIGATION: THE BODY’S RESPONSE TO EXERCISE
(Pages 208–209)
Prediction
(a) There are a number of possible predictions that students could make in this investigation. However, based on their prior
knowledge and experience most students are likely to predict that exercise will cause both pulse rate and blood pressure to increase.
Experimental Design
(b) Review the sample report in Appendix A4, Figure 1, for a model to use in this investigation.
Variables
Dependent variables—pulse rate (beats/min), blood pressure (mm Hg, systolic/diastolic)
Independent variables—exercise (walking on treadmill at 6 km/h)
Controlled variables—duration of exercise, type of exercise, time of day, position of student (i.e., standing, sitting, or lying
down before and after exercise)
Materials
stopwatch or watch with second hand (or a digital heart rate monitor)
sphygmomanometer and stethoscope (or digital sphygmomanometer)
treadmill (or step stool; or other exercise method)
Procedure
1. Arrange for nine student volunteers from the class. Include yourself as the tenth person.
2. Measure the resting pulse rate and blood pressure of each participant.
3. Have each student walk on the treadmill (at 6 km/h) and measure their heart rate and blood pressure after 1, 3, and
5 min of exercise.
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Unit 3 Student Book Solutions
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Unit 03 - Student book
9/25/03
1:00 PM
Page 103
4. Stop the treadmill after the last measurements are taken (i.e., after 5 min) and measure the heart rate and blood pressure 1, 3, and 5 min after stopping.
5. Record the measurements in the appropriate observation tables.
Safety Precautions
1. Ensure that no participating student has any cardiovascular, respiratory, or other conditions that might put him or her
at risk during the exercise part of this investigation.
2. Ensure that the pressure cuff of the sphygmomanometer is not over-inflated (higher than 180 mm Hg) or kept inflated
for more than 1 min.
Observations
See sample data in Table 1 and Table 2 below.
Table 1 Heart Rate
Resting
heart rate
Heart rate
after 1 min
of exercise
Heart rate
after 3 min
of exercise
Heart rate
after 5 min
of exercise
Heart rate
1 min after
stopping
exercise
Heart rate
3 min after
stopping
exercise
Heart rate
5 min after
stopping
exercise
1*
68
74
80
86
80
74
68
2
70
76
82
88
82
76
70
3
71
74
77
80
78
75
72
4
69
71
75
78
76
74
71
5
75
80
85
90
90
85
80
6
74
78
80
82
80
76
71
7
72
75
78
82
81
78
72
8
76
80
86
94
92
88
86
9
71
74
78
81
78
75
71
10
73
75
77
79
77
75
73
Resting
blood
pressure
Blood
pressure
after 1 min
of exercise
Blood
pressure
after 3 min
of exercise
Blood
pressure
after 5 min
of exercise
Blood
pressure
1 min after
stopping
exercise
Blood
pressure
3 min after
stopping
exercise
Blood
pressure
5 min after
stopping
exercise
1*
118/76
122/76
126/76
130/74
126/76
120/76
116/76
2
120/80
122/80
124/80
126/80
124/80
122/80
120/80
3
121/81
124/81
128/81
132/81
130/81
128/81
126/81
4
119/81
122/81
125/80
127/79
125/79
123/79
120/79
5
124/84
128/84
134/84
138/85
135/84
132/84
128/84
6
123/83
126/83
128/81
130/78
125/78
121/78
119/78
7
120/80
122/80
124/80
126/80
124/80
122/80
120/80
8
125/86
130/86
135/87
140/90
138/87
135/86
130/86
9
119/81
122/81
125/80
127/80
125/80
123/80
120/81
10
122/82
124/82
125/80
127/80
126/80
124/80
122/80
Student
Table 2 Blood Pressure
Student
*Student carrying out the investigation.
NEL
Section 3.11
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Unit 03 - Student book
9/25/03
1:00 PM
Page 104
Analysis
(c) Students should prepare a graph like the sample below.
Heart Rate and Blood Pressure
during and after Exercise
140
110
Systolic Pressure
100
120
90
110
Heart Rate
100
80
90
Heart Rate (beats/min)
Blood Pressure (mm Hg)
130
70
80
Diastolic Pressure
60
70
0
1
2
3
4
5
6
7
8
9
10
Time (min)
(d) Answers will vary; for example: At 5 min after the exercise had stopped my heart rate and blood pressure had returned
to resting levels. This recovery is (faster than) (slower than) (about the same as) that of most of the other participants.
(e) Exercise increased both the pulse rate and blood pressure during exercise. After exercise the pulse rate and blood pressure decreased again. There is considerable variation among the students in the amount by which their pulse rates and
blood pressures increased during, and then recovered after exercise.
Evaluation
(f) Answers will vary. It is likely that students will conclude that their prediction was correct.
(g) Students may have experienced some difficulties measuring blood pressure accurately, especially if they have access
only to a manual sphygmomanometer.
Synthesis
(h) During times of stress, such as exercise, the sympathetic nerve stimulates the adrenal glands, which release the
hormone epinephrine (adrenaline). Epinephrine and direct stimulation from the sympathetic nerve increase heart rate
and breathing rate. The increased heart rate provides for faster oxygen transport while the increased breathing rate
ensures that the blood contains higher levels of oxygen. Both systems work together to improve oxygen delivery to the
muscles. A secondary but important function is the increased removal of wastes such as carbon dioxide from the
muscles. Blood pressure increases because the blood circulation to non-essential parts of the body during exercise
(e.g., digestive system) is restricted allowing increased blood flow to the muscles.
(i) The autonomic nervous system keeps functions like heart rate and blood pressure within normal ranges. It is separated
into two active parts: the sympathetic and the parasympathetic. When the sympathetic part is dominant, the heart rate
and blood pressure increase and digestion slows down. Conversely, when the parasympathetic part is dominant, heart
rate and blood pressure decrease and digestion increases. When you inhale deeply, receptors in your heart recognize
that the blood flow to the heart has increased, and a message is sent to your brain. Supplying oxygenated blood to the
body is the primary purpose of the circulatory system. If the body requires more oxygen, the heart responds by
pumping the blood out to the lungs faster where it becomes oxygenated and then is pumped back to the body that needs
the oxygen. To do this, the autonomic nervous system temporarily weakens the parasympathetic responses. Your heart
rate increases—your sympathetic responses strengthen for a few seconds. The nervous system can only adjust the rate
and strength of the heartbeat. The nerves to the heart (sympathetic and parasympathetic) do not initiate each heartbeat;
they can speed the heart up and increase the force of contraction, or slow it down and reduce the force of contraction.
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Unit 3 Student Book Solutions
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Unit 03 - Student book
9/25/03
1:00 PM
Page 105
(j) When exercise starts the muscles begin to use more oxygen and generate more carbon dioxide, which diffuses into the
blood stream. The brain receives a message that the carbon dioxide level in the blood is rising. The brain then sends a
message to the adrenal gland, which secretes adrenaline (epinephrine). The adrenaline causes the blood vessels to nonessential organs to constrict thereby restricting blood flow to these organs. Blood flow is now concentrated to the active
tissues—the muscles. The adrenaline also signals the heart to increase its rate and force of contraction. This increases
blood flow and blood pressure to the muscles. The increased blood flow to the lungs increases the oxygen level and
decreases the carbon dioxide levels in the blood stream, which signals the brain that changes have been made in
response to the original messages. After exercise, the carbon dioxide level in the blood decreases, which signals the
brain, and the heart rate decreases. The heart rate and blood pressure are maintained at a level that keeps the concentration of carbon dioxide in the blood at an acceptable level. This continuous negative feedback process regulates the
heart rate during and after exercise.
(k) Recovery time is the time required for the heart rate and blood pressure to return to resting levels after exercise. This
time is an indicator of the body’s ability to maintain homeostasis. Generally speaking, the shorter the recovery time
the fitter the individual. A short recovery time indicates that the heart has not been overstrained during the exercise.
As your fitness improves your heart rate should decrease more rapidly after exercise.
(l) Average pulse rate for young adults (between the ages of 14 and 21) is between 76 and 85. Systolic blood pressure
ranges from 110 to 150 and diastolic pressure ranges from 60 to 80. Average blood pressure for young people is
120/80. The National Institutes of Health indicates that the normal range for adults 18 years and older is <130 and <85.
(m) Answers will vary. Students may suggest other variables such as different forms of exercise, longer exercise and
recovery times, different equipment, or age and sex differences.
3.12 THE EXCRETORY SYSTEM
SECTION 3.12 QUESTIONS
(Page 214)
Understanding Concepts
1. Excess amino acids are broken down in the liver in a process called deamination.
2. The amino group left over from the deamination process is converted into ammonia. Nitrogen compounds, such as
ammonia, are poisonous. Two molecules of ammonia can combine with carbon dioxide to form urea. Urea is much
less (100 000 times) toxic than ammonia.
3. Nephrons carry filtered fluids from the blood to the urinary bladder. Nephrons permit the selective reabsorption of
filtered fluids and are the functional unit of the kidney.
4. (a) D—the kidney
(b) E—the ureter
(c) C—the renal artery
(d) F—the urinary bladder
5. Filtration involves the movement of fluids from the glomerulus into the Bowman’s capsule. Reabsorption involves the
movement of fluids from the nephron into the extracellular fluid and eventually the capillary network. Secretion
involves the selective transport of fluids from the capillary network into the nephron (the collecting duct).
6. Kidney stones are formed by the precipitation of dissolved minerals from the blood. They are a problem because they
may become lodged in the renal pelvis or move into the narrow ureter, blocking the flow of urine from the kidney to
the bladder. Sharp-edged stones may also cut or tear delicate tissue as the stone moves toward the bladder, causing
terrible pain in the process.
7. Blood containing a drug would be force-filtered in the glomerulus. Liquid with the drug dissolved in it would thus be
forced out into the cavity of the Bowman’s capsule. From there, the liquid containing the drug would move down the
descending arm of the loop of Henle. The drug would become more concentrated because water is moving out of the
tubule at this part of the nephron. In the loop of Henle and in part of the ascending arm, some of the drug might move
back into the tissues, depending on its solubility in the tubular liquid and its permeability with respect to the tubule
tissues. Any of the drug that remained in the tubule would become more concentrated as more water was removed from
the tubule during its passage to the collecting ducts. Eventually, the drug would enter the urinary bladder and be
excreted in the urine.
NEL
Section 3.12
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