Download Grade 11 College Biology – Unit 3

Grade 10 Applied Science - Biology
More on the Heart
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Pulse is when blood is pushed out of the heart under pressure. At that moment, the arteries stretch
and increase in diameter. This is felt as your pulse. Pulse is measured in BEATS per MINUTE (bpm)
Resting normal pulse (bpm)
Baby
100 - 160
1 – 10 years old
60 – 140
10+
60 - 100
Athlete
40 - 60
Two numbers in blood pressure
 Systole – Blood under pressure LEAVING the heart
 Diastole – Ventricles filling up with blood
Normal Blood Pressure of a healthy adult is 120 / 80
Factors that can change blood pressure
Increase (High Blood Pressure (140 / 90)) – HYPERTENSION
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Too much stress
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Poor diet (high in fat and cholesterol
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Lack of exercise
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Weight / obesity
Decrease (Low Blood Pressure ( <90 )) - HYPOTENSION
Sound of the Heart
 First, the atria are relaxed while they fill with blood (DIASTOLE)
 During SYSTOLE, the ventricles contract pushing blood out. This pressure causes the AV valves to
close. This is the LUBB sound
 As the ventricles relax, the SEMI LUNAR VALVES close to prevent the backflow of blood. This is the
DUBB sound.
Heart Beat
 The MYOGENIC MUSCLE surrounds the heart.
 A group of nerves in the heart act as a PACEMAKER. It sets the rhythm.
 Another group of nerves passes an impulse to the ventricles to cause them to contract at the very
same time.
Grade 10 Applied Science – Biology
Circulatory System – The Heart
The heart is a hollow muscular organ about the size of a fist. It contracts at regular intervals to pump blood through
the heart’s chambers and into the AORTA which carries blood to smaller arteries that transport blood throughout the
body. ARTERIES are very elastic vessels that stretch each time the heart pumps blood. CAPILLARIES are tiny
blood vessels connecting arteries to veins. It is in the capillaries that the exchange of nutrients, salts, oxygen and
carbon dioxide occurs between cells and the blood. VEINS carry blood back to the heart. NOTE: the blood does
NOT exert the same pressure on the walls of veins as it does no the arteries.
PULSE RATE is measured by the number of times the heart contracts per minute. What we feel is the expansion
and contraction of an artery as the blood is pushed through it. Most arteries are protected by muscle and they are not
located near the surface. However, some arteries are close enough to the surface to allow you to feel the pulse of
blood through them. Examples include the CARTOID ARTERIES in the side of the neck just below the jaw and the
RADIAL ARTERIES on the inside of the wrist.
AEROBIC RESPIRATION at the cellular level provides energy to the cell, using oxygen and sugar while releasing
carbon dioxide and water along with energy. During exercise, the heart rate and respiration increase allowing the
lungs to bring adequate oxygen to the cells of the body. If the exercise is strenuous or prolonged, energy is provided
by ANAEROBIC RESPIRATION. This process does NOT require oxygen. It provides quick energy, but it also
produces LACTIC ACID that causes muscles to fatigue and cramp. Lactic acid requires oxygen to break down. How
will the circulatory system operate to regain homeostasis in the event of lactic acid buildup?
TASK
You will be
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Monitoring your heart rate during various activities
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Comparing heart rates after performing different exercises
MATERIALS
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Watch with a second hand or stopwatch
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Data sheets (attached)
Data Sheet 1
ACTIVIY
Your pulse rate
(beats per minute)
Your partner’s pulse rate
(beats per minute)
Class Average
(beat per minute)
Resting
Standing
Data Sheet 2
Pulse Rate (beats per minute)
ACTIVITY
Resting
Exercise #1
Exercise #2
Person 1
Person 2
Person 3
Your group
average
METHODS
NOTE
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If you have asthma or other breathing issues, please modify exercises to by less strenuous. Be your own
monitor.
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If you plan to run stairs or step on a chair, you require a “spotter” to watch you will exercising.
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Sit quietly on your stool for two minutes
Determine your resting pulse rate (use a CARTOID ARTERY in your neck) by pressing two fingers against your
artery and counting the number of pulses in 15 seconds and multiplying by 4 (15 X 4 = 60 seconds or one
minute)
Repeat this step
Record your resting pulse rate on Data Sheet #1 and Data Sheet #2
Record your partner’s resting pulse rate on Data Sheet #1
Record your data on the chalkboard and calculate a Class Average
Stand for two minutes BUT remain still
Take your standing pulse rate using the same method
Record this data and your partner’s standing pulse rate on Data Sheet #1 and the chalkboard
Calculate the Class Average Standing Pulse Rate
Design an “Exercise” experiment with two different exercises (e.g., Jumping Jacks for one minute, running up
and down the stairs 2X, running on the spot for three minutes, skipping rope, walking). Your experiment design
MUST include a hypothesis, methods (including materials and appropriate controls) and data collection chart.
Review the experiment with the teacher
Conduct your experiment collecting the data as shown in Data Sheet #2
Prepare a FULL LAB REPORT and answer the questions
Questions
1. From Data Sheet 1, were “Sitting” and “Standing” heart rates the same?
2.
Did your heart rate match the class average?
3.
What was the range of heart rates in the class? Provide two reasons for any difference.
4.
From Data Sheet #2, how did exercise affect heart rate?
5.
Which activity seemed to cause the greatest increase in heart rate?
6.
Why did your body change its heart rate during exercise?
7.
Name two factors other than age that could impact a person’s resting heart rate.
8.
Recalling the heart is a muscle, why do you think regular aerobic exercise is important and smart?
9.
When you exercise, your tissues need more oxygen. This experiment explored one process: the heart.
Yet, the heart is only one part of the overall cardiovascular and pulmonary systems. Recall, red blood cells
pick up oxygen in the lungs and carry it to the muscles. What are other ways your body might increase the
supply of oxygen to the muscles. Provide two ideas.