Marie McClary
Unit 4 Conclusion Questions 100 points possible
Activity 4.1.1
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How do you think bones, muscles and joints work together to move the body?
 Bones give structure and muscles contract to allow the joints to move our bodies in
different ways.
Your friend Andre comes to school and tells you that he has a dislocated shoulder. Based on
what you now know about joints, what do you think this means?
 The shoulder is a ball and socket, so the ball has popped out of its socket.
How are tendons and ligaments similar and how are they different?
 Tendons and ligaments are both connective tissues, but tendons connect bone to
muscle and ligaments connect bones to bones.
Explain why the elbow joint of a cow and the elbow joint of a human have similar, but not
identical structure. Think about the actions each organism completes with this limb.
 Both of the elbows have a radius and an ulna but the cows elbows are a hinge joint
that only allows them extend. The human’s elbows allow us to move in all kinds of
directions because they are more complex.
What type of joint is the hip joint? Describe the type(s) of movements this joint can perform.
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The hip is a ball and socket joint which allows movement in any direction.
Activity 4.1.2
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Describe how your range of motion compares to the range of motion of those in your group.
Why might there be differences?
 My range of motion was in the higher category because I have been flexible since I
was a little girl because I stretch so often.
Which type of joint do you think allows for the greatest number of different movements?
Explain your reasoning.
 Ball and socket allows for the most movement because the joints have more of a
variety of movement.
What factors influence range of motion of a joint?
 Age, gender, flexibility, injury, fat tissue, and activity levels are all factors that affect
the range of motion for each person.
Explain how a person can improve flexibility at the joints.
 A person can stretch to condition the flexibility of the joints.
Your goniometer breaks. Describe another way you might be able to measure range of
motion.
 You could use an inclinometer which uses a stationary arm, protractor, fulcrum, and
movement arm to measure angles from axis of the joint.
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Your favorite team is winning the championship game. You drop to one knee, tip your head
back, raise one hand over your head, clench your fist and yell, “Yes.” Use the proper terms
to describe the movements undertaken by your joints.
 When you drop to your knees you are using abduction to bring your knee close to
the body. When you tip your head back you are using ornaduction since the neck is
pivot joint, then when you shoot your hand in the air you are using extension. When
you clench your fist you are using depression of your fingers.
You overhear two men at the gym talking about their extensor muscles of the forearm.
Based on what you know about the motion at joints, how would you describe the
movement of these muscles?
 The muscles probably allow them t stretch out so that they can do more exercises.
Activity 4.2.1
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Describe the differences you see in the three types of muscle tissues.
 Skeletal muscle is striated and looks like long fibers. Cardiac muscle is striated and
has visible nuclei. Smooth muscle is nonstriated and has a wave type structure with
visible nuclei.
What does it mean when we say a muscle contracts involuntarily? Describe one body
function that is linked to an involuntary muscle contraction.
 Involuntarily means that you aren’t controlling the movement, t just happens. The
heart pumps involuntarily.
Describe how the structural makeup of a muscle contributes to the muscle’s ability to do its
job.
 A muscles structure consists of connective tissue and muscle fibers, which work like
a rope or rubber band to stretch and contract. The connective tissues’ elasticity and
distensibility help to ensure that the tension developed by the muscle is smoothly
transmitted and that a muscle will return to its original shape after being stretched.
Using your knowledge of tissues, what type of tissue do you think makes up the three layers
of membrane you encountered in your muscle?
 I think it is made of smooth muscles because its function is to cover organs and help
it retain its shape.
Explain how you know which attachment of a muscle is the origin and which attachment is
the insertion.
 The insertion of the muscle is the end of the muscle attaching to the freely moving
bone of its joint. The origin of the muscle is the end of the muscle attaching to the
relatively fixed bone of its joint.
Your mom comes back from the doctor and says she has pulled her tibialis anterior. She
knows you are taking Human Body Systems and asks you to tell her about her injury. Based
on the classroom discussion, what can you deduce about this muscle?
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She has injured the muscle on the backside of her tibia. When you are cold, your muscles
begin to contract involuntarily and cause you to shiver. Why do you think this occurs? How
does the contraction of muscles help the body maintain homeostasis?
 Shivering causes you to involuntary contract and relaxes your muscles which will
increase heat production.
Activity 4.2.2
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Look at your Maniken®. Explain to your client why you need multiple exercises to effectively
build and tone the muscles of the chest.
 You have different muscles in your chest with different insertions and origin so you
have to use different exercises to condition all muscles.
Think about the action of the muscles you have built. Describe at least two exercises that
will strengthen the muscles of the chest. Make sure to note the specific muscles that are
targeted in each exercise. Add information about these exercises to your lab notebook.
 Doing push ups would strengthen the pectoralis major. Pulling your arms inward
while holding weights and meeting them in the middle would work all the muscles
in the chest. Doing “Around the Worlds” will also strengthen muscles in the chest.
Explain how the structure and function of one of the muscles of the chest relates to some of
muscle rules you learned in Activity 4.2.1.
 They are large and the direction of the muscle fibers shows the way they work.
Explain how the muscles pectoralis major and serratus anterior show two different ways in
which muscles are named.
 The serratus anterior is named for its relation to the bone and its origin and muscle
fibers. The pectoralis major is named for its size and location in the body.
Are the muscles of pectoralis major adductors or abductors? Explain.
 They are major abductors because they can push the shoulder away and bring it
closer to the body.
Activity 4. 2.4
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When you see the glycerinated muscle fibers shorten, what do you think is actually
happening in the muscle cells? Think about what you just saw under the microscope.
 The muscles are contracting.
Did your muscle samples eventually relax and return to the length they were before
contraction? Thinking back to the muscles rules and how your know muscles work, why
does this make sense?
 They did relax and return relatively to the length they were before. This makes
sense because the energy they use to contract eventually gets expelled.
Which solution produced the greatest percent contraction of the muscles? What does this
tell you about the requirements for contraction?
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The solution with both sodium and glycerol produced the most contraction. Muscles
need both sodium and glycerol to contract fully.
Think about the way in which organ systems work together to kick your leg or swing your
arm. Besides the skeletal and the muscular system, what other systems do you think are
involved in moving the human machine?
 The nervous system because in order for muscles to move, there needs to be a
signal to the brain.
Activity 4.2.5
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How do multiple human body systems work together to cause muscle contraction and
movement of the body?
 Muscle contractions resulting in movement are a symphony of coordination
between nerve impulses, brain cells and muscles. It is truly shown how intricate the
process is when muscles are retrained to work prothetic devices.
Your friend tried to convince you that the only reason to drink milk and to make sure you
get enough calcium is so you can build strong bones. Can you offer him/her another reason?
 Calcium regulates muscle contraction, including the heartbeat. It also plays a key
role in normal blood clotting.
Explain how it is that actin and myosin in the sarcomere never actually shorten and yet the
muscle as a whole does.
 Actin and myosin join together making it seem as though the fibers have shortened.
How do ions and electrical charges play a role in communication with the muscle?
 Signals from the CNS are sent through efferent pathways for actin and myosin to
bond and then a message from the muscles is sent back through afferent pathways.
Summarize the science behind rigor mortis. Why is this state a temporary condition?
 ATP is still needed for actin and myosin but since the CNS isn’t working, muscles stay
contracted. Eventually lysosome will get free and cause muscles to relax.
Using what you know about rigor mortis and about energy, what do you think happens
inside your muscle when you get a muscle cramp? Why is this not a permanent condition?
 Actin and myosin come together for your muscle to contract, but for some reason
ATP could not reach it. But the actin and myosin will eventually release because the
body keeps making ATP.
Activity 4.2.6
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Given the placement of the ulnar nerve, what type of forearm muscles do you think this
nerve stimulates? Explain. HINT: What type of muscles is found on the ventral side of the
body?
 The pectoralis muscle is located on the ventral side of the body near the ulnar nerve
meaning that it is stimulated by it.
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Explain how the placement of the ulnar nerve is linked to the pain and discomfort you feel
when you bang your “funny bone.”
 The ulnar nerve lies in a small space between the medial epicondyle of the humerus
and the olecranon of the ulna. There is only skin over this space with no bones or
muscles to protect it causing blows to your humerus to be quite painful compared
to other less sensitive areas of the body.
Given the placement of the radial nerve, what type of muscles do you think this nerve
stimulates? Explain. HINT: What type of muscles is found on the dorsal side of the body?
 A muscle called the infraspinatus is located on the dorsal side of your body. It is
most often stimulated by the radial nerve because it is located so near to it.
What do you think would happen to a person’s ability to use his/her arm if the radial nerve
were damaged?
 Severe damage to the radial nerve could force big changes in a person’s life as it is
responsible for doing so many tasks. This nerve controls movement in the triceps
and sensation in a portion of the hand while also allowing the wrist and fingers to
move. When damage to the radial nerve occurs, all of these functions are put in
jeopardy.
Explain how the central and the peripheral nervous system work together to allow you to
pick up a can of soda. Mention muscles of the forearm in your answer.
 People with jobs such as computer programmers who spend an excessive amount of
time typing on their computers, busy handymen with lots of time to hammer away
at things, or even teachers with many papers to grade could be at risk for carpal
tunnel syndrome. All of these people should take regular breaks to ensure that they
are not in danger of this syndrome.
Describe at least three different jobs that put the worker at risk for carpal tunnel syndrome.
How can these individuals lower their risk of injury?
 Action potentials must be released for muscle contraction to even begin. Motor
neurons coding for the movement are sent to that specific muscle.
What happens at the junction between a nerve and a muscle to initiate muscle contraction?
 A stimulus is conveyed to cause contraction.
Activity 4.3.1
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How does the structure of smooth and cardiac muscle differ from the structure of skeletal
muscle?
 Skeletal muscles are striated along with cardiac muscles, but unlike smooth muscles.
These types of muscles are also branched, making them similar to smooth muscles
but different from cardiac muscles that are unbranched. The only sure difference is
that skeletal muscles are multinucleated while both smooth and cardiac are
mononucleate muscles. All three of the muscle types have unique locations.
Explain how each of the three types of muscle assist with moving blood around the body.
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Cardiac muscles can probably be considered the most important when it comes to
moving blood around the body as they are responsible for pumping blood. While it
is not all they are responsible for, smooth muscles in the body regulated the flow of
blood and blood pressure by controlling the contraction and relaxation of the
muscles in the arteries. Skeletal muscles are mainly for maintaining posture and
things such as that. Certain body positions allow blood to flow through the body
with less difficulty therefore assisting with moving it.
What role do valves play in the heart?
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Valves make sure the blood doesn’t go in reverse and instead continues in a steady
flow.
Which structure in the heart functions as the natural pacemaker? What does this term
mean?
 The sinoatrial node is generally referred to as the body’s natural pacemaker,
because it is what always initiates cardiac contraction by sending electrical impulses
to the rest of the heart.
How does the movement of the electrical impulse relate to the contraction of the chambers
of the heart?
 Electrical impulses in the heart always begin in the right atrium as that is where the
sinoatrial node is located. The start of the impulse controls which chamber will
contract next as the impulse travels through the whole of the heart. At one point,
the electrical impulse is even delayed to allow the atrioventricular node to allow it
to perform a specific task.
What is the difference between pulmonary circulation and systemic circulation?
 Pulmonary circulation affects only the right side of the heart, pumping blood to the
lungs to take oxygen into the hemoglobin while it also gives off carbon dioxide. This
is then returned to the left side of the heart which then pumps blood out to the
entire body. The blood that is being pumped to the entire body will eventually
return to the right side of the heart to allow the cycle to begin again.
Thinking about function, explain why the left ventricle is much more muscular than the right
ventricle.
 While the right ventricle only has to pump blood into the lungs to be oxygenated,
the left ventricle then has to send the blood through the entire body.
Describe the role of smooth muscle in two human body systems other than the
cardiovascular system.
 Smooth muscle lines the wall of the stomach and helps the organ to churn up food
that has not already been broken down mechanically, making it necessary for the
digestive system to function. In the urinary system, smooth muscle is located in the
ureters and is responsible for expelling urine.
How does electrical communication in the heart compare to electrical communication in
skeletal muscles?
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Skeletal muscles require outside forces for electrical communication to occur as
action potential must occur before any movement takes place. Electrical
communication in the heart starts and ends there without any help from other body
systems.
Activity 4.3.2
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What do you notice about the width of an artery wall versus the width of a vein wall? Why
does this make sense given the function of the vessels?
 Arteries have much wider walls as they contain more layers of muscle than veins.
This is because arteries must be able to transport high-pressure blood throughout
the body unlike veins.
Capillaries function in gas exchange. Describe at least two ways capillary structure is related
to this function.
 Capillaries must be able to diffuse oxygen and carbon dioxide with ease. Their walls
are very thin while also having a large surface area to make this possible.
How do capillaries interact with the respiratory system? Make sure to mention specific
structures of the respiratory system. Refer back to your graphic organizer if you need help
remembering key anatomy.
 The interaction above is fairly simple. Oxygen from the capillaries must be able to
move from the alveoli to the blood so that it can then be transported through the
body.
Which artery do you think is made of thicker muscle, the aorta or the pulmonary artery?
Why? Refer back to your heart box to visualize the path of these vessels.
 The aorta would have to be made of thicker muscle as it has to transport blood from
the heart to the entire body while the pulmonary artery just sends blood to the
lungs to be oxygenated.
Describe two ways blood is helped back to the heart in veins. Mention relevant body
systems.
 Both the superior and inferior vena cava allow blood to be taken back into the
heart. Veins do not have muscles with which to send the blood though, so they must
rely on other muscles throughout the body to help them get the blood back to
where it needs to be.
Explain why a person who spends most of the day on his/her feet is more likely to develop
varicose veins.
 Spending an extended amount of time on your feet will increase the pressure in
your lower body, which is what causes varicose veins in the first place. Excessive
pressure causes the thin veins to gnarl and visibly protrude.
Activity 4.3.3.
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Why do you think the clay used to represent veins is thinner than the clay used to represent
arteries?
 Arteries are thicker as they must withstand blood with a higher pressure than veins.
What do you think would happen in the body if blood flow to right femoral artery was
blocked? How would this change impact movement of blood and movement of the body?
 Blood would not be able to flow as it did before because it previously passed
through the right femoral artery. This would restrict certain movements that were
easy for the person to perform before the blockage.
Suggest a reason why the veins of a bodybuilder “pop out” more than a person who does
not lift weights. Why don’t we see arteries “pop out”?
 Body builders lift weights so often that they put an excessive amount of pressure on
their veins that most people do not. Varicose arteries do not exist because not only
are they located much deeper in the skin than veins, but they are also equipped to
handle blood with a higher pressure.
Why do you think arteries, veins and nerves always travel together? Provide an example
that illustrates your reasoning.
 Nerves require a constant blood supply to function as they should, which makes it
essential that they travel along with arteries and nerves that can give them the
blood they need.
Activity 4.3.4
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Which do you think are the two, most common places to detect pulse and count the heart
rate? Why?
 People usually monitor their heart rate either by feeling for it in their neck or their
wrist as that is most often where it is easiest to find.
What are some factors that can increase or decrease the heart rate and the beat you feel at
each pulse point?
 Factors that influence your heart include how relaxed or excited you are, what you
are currently doing and whether it is physically or mentally stressful. Different pulse
points you try, such as in the foot, may be differ because of the way the blood is
flowing throughout your body. If everything is in order, all of your pulse points
should be relatively the same.
Athletes often have a very low resting heart rate. What does this tell you about the health of
their heart? Explain.
 A very low resting heart rate means that your heart has become accustomed to
more strenuous activities, such as running or lifting weights. A low resting heart rate
usually implies that someone’s heart is healthy enough for demanding physical
activity.
What are consequences of having a low cardiac output? How will other body systems be
affected?
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If a person’s cardiac output is lower than normal, the tissues can suffer or blood
pressure can become unhealthy. This could affect the immune or respiratory
systems if your heart is required to work harder for your body.
Dehydration reduces blood volume. How would this affect cardiac output? Explain.
 Decreased blood volume forces your body to compensate by keeping more sodium
in the blood than is actually needed in regular situations. Too much sodium in the
blood will then cause increased blood pressure and make it more difficult for cardiac
output to function normally.
Describe how each of the following could impact stroke volume.
Damage to the conduction system of the heart
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Damage to the conduction system of the heart will prevent the heart from
contracting and relaxing as like it supposed to do. This will cause the stroke volume
to decrease because not as much blood will be pumped if the heart is not
functioning as it should.
A blockage in one of the coronary arteries
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The heart needs oxygen that is from the coronary arteries to work as it should.
When the coronary arteries are blocked, oxygen is decreased therefore interrupting
regular stroke volume.
Activity 4.3.5
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What is your ABI? What does this value tell you about your risk of peripheral artery disease?
 Ankle-Brachial Index tells patients if they have no blockage, any blockage, or rigid
arteries. The amount of blockage establishes the level of peripheral artery disease.
Explain how PAD might impact other body systems.
 PAD affects many different arteries like arteries that lead to the leg, kidneys,
intestines, and brain. So the digestive system, urinary system, and the muscular
system are just some examples of body systems that are affected.
How do the chemicals in smoke relate to the development of atherosclerosis?
 The chemicals in tobacco smoke harm your blood cells and damage the function of
the heart and the structure of the blood vessels. Plaque builds up in the arteries and
it hardens and narrows the arteries.
Why do you think diabetics are also at increased risk for PAD?
 A person with diabetes has problems with glucose and having extra glucose in the
blood makes it more likely to get stuck in a vessel and form clots.
Explain why untreated PAD can lead to the loss of a leg. Make sure to mention the specific
arteries of the leg.
 Since the femoral, popliteal, and posterior tibeal artery doesn’t allow the leg to
receive enough oxygen, it dies and results in an amputation.
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Explain how the endocrine system and the kidneys help play a role in regulating blood
pressure.
 The endocrine system and the kidney both regulate the water in the blood stream.
The amount of water in the blood stream affects the volume of the blood, causing
the blood pressure to also be affected.
Activity 4.4.1
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Provide at least two examples of the opposite effects of the sympathetic and
parasympathetic divisions of the nervous system.
 Parasympathetic releases saliva and controls hormones, while sympathetic controls
movement and speaking.
Explain how the respiratory and the cardiovascular system work together to meet the
demands of the working muscle.
 The respiratory system oxygenates the blood that the cardiovascular system pumps
to the muscles in the body.
Our body sweats to stay cool during exercise. How does this seem to counteract the action
of the urinary system?
 When the body sweats, it expels water that the urinary system balances.
List and describe at least three things a runner can do before a race to prepare the body for
the demands it is about to endure.
 In order for a runner to be ready for a race they should eat a healthy meal full of
carbs in order to maintain the energy level, stretch all of their muscles in order to
prepare them for the run, and they should do some warm ups to get their
respiratory system “awake and ready” for the race.
When you set out to jog five miles, your body first uses the ATP that is floating around in
your system. Describe the systems that your body relies on for ATP after this point.
 Your body uses the lactic acid cycle so it can perform glycolysis and then start
aerobic respiration to use oxygen to make ATP.
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Which muscle energy system(s) is (are) used for each of the following activities? Make sure to
explain your reasoning.
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The 50 meter dash
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A game of basketball
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Lactic system- When you run in a sprint you don’t usually breathe until you have
finished the sprint.
- A game of basketball is lengthy and full of energy, throughout the whole game a
person breathes heavy and preforms cellular respiration.
A single football play
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Lactic system- If it were an entire game of football then it would be aerobic but
since it’s just one single play, it’s just a burst of energy rather than energy for an
extended amount of time.
Weight lifting
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Lactic- You can feel your muscles start to burn but you aren’t inhaling a bunch of
oxygen in order to perform cellular respiration.
Running a marathon
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Aerobic system- Throughout the entire marathon, the runner breathes heavy which
causes the body to preform cellular respiration.
Activity 4.4.2
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Use the data in your table to calculate the percent loss of grip strength that occurs between
the 0-20s and 60-80s intervals. Describe a situation in which such a loss of grip strength is
noticeable in your day-to-day life.
 58% When walking up many stairs, the body starts to get sluggish.
Use the data in your table to calculate the percent change in amplitude (∆mV) in electrical
activity that occurs between 0-20s and 60-80s. What accounts for the difference in the
percent change observed in grip strength and ∆mV for the two time intervals? What’s going
on in your muscle?
 209% The muscle is sending signals to work much harder to produce the same grip
as before because it is out of energy.
How did your mean grip strength in the last 20 seconds of the experiment compare to the
60-80s interval? Explain this result.
 The 80-100 second interval was about twice as much as the 60-80 second interval
because they got a new rush of energy that made them work harder.
Do the findings from your experiments support or refute the practice of “coaching from the
sidelines” at sporting events? Can you exert “mind over muscle?”
 It supports the idea because there is a noticeable increase of energy because
motivation get the person to push harder than they were before.
What role does the nervous system play in muscle fatigue?
 The body tries to get the muscle to use less energy since it has already used up all of
its energy.
Is the hand grip test an example of an isometric or an isotonic muscle contraction? Explain
your reasoning.
 Isometric since the body wasn’t moving while the test was going on.
What conclusion can you draw about the number of individual muscle fibers that fired in the
last 10 seconds as compared with the first 10 seconds?
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The muscle fibers are more fired up in the beginning of the test best they had more
energy.
What energy systems does your body use to support the 100s trial in the experiment? Refer
back to information presented in Activity 4.4.1.
 All three energy systems support this experiment. The first two will last for most of
it and towards the end of the experiment, there is a larger amount of ATP ready to
be used.
Describe one way a person can train to overcome muscle fatigue.
 Working muscle will train it to be stronger and to use energy more effectively.
Activity 4.4.3
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Describe how two of the performance enhancers you discussed in the summit affect human
body systems. Be sure to include both positive effects and negative effects.
 Caffeine provides energy but it doesn’t last long. Steroid/ anabolic steroid increase
muscle build up but can cause liver abnormalities and tumor and higher blood
pressure.
Some performance enhancers are only banned in specific sports. Why do you think betablockers are banned in sports such as archery or gymnastics?
 Both sports depend on balance and steadiness and Beta Blockers steady a person’s
anxiety and muscles which allows the person to have complete control over their
body and better accuracy.
Unfortunately, it is not just athletes who are turning to these types of treatments. Many
young men and woman, unhappy with their bodies, may turn to drugs in the hopes of added
muscle mass, increased size or a leaner body. Why do you think students your age might
consider using these drugs and what would you say to those who are considering it?
 They know that the drugs will increase the person’s strength, muscle mass, or breast
size but they don’t consider the long term effects of the drugs. I would tell them
about how there are different ways to increase strength and to be happy with their
body because you don’t want to ruin your health just for you teenage body.
“Gene doping” has recently been added to the WADA prohibited list. What do you think this
term means?
 They take control of gene transfer techniques in order for the body to use the
maximum amount of muscles.
Finnish cross-country skier Eero Mantyranta won two gold medals in the 1964 Winter
Olympics. It was not until decades later that scientists identified a genetic mutation in Eero’s
family that causes an excessive response to EPO. How do you think this “natural advantage”
contributed to Eero’s success in endurance sports?
 EPO controls red blood cell production and so if a person has more red blood cells
then the body is more oxygenated. The muscles won’t get as tired if they receive
more oxygen. So Eero’s body could push it harder for a longer time than the average
athlete.
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Describe at least two other genetic changes (either natural or through genetic
enhancement) that might improve the performance of an athlete. Make sure to explain how
the gene change is linked to increased chances for success.
 A person can have manipulated genes that enhance lung-power so they can handle
more work on their lungs and they can also have genes that are resistant to weight
gain no matter what the person eats.
Throughout this course, we have been looking at medical interventions as a means to
preserve and better life as we know it. Explain how performance enhancers show another
side of medical interventions.
 Instead of trying to improve the unhealthy person into a healthy person,
performance enhancers are taking an already healthy person and trying to push
their health to the max which can affect the body in both positive and negative
ways.