Unit 4 Conclusion Questions 100 points possible
Activity 4.1.1
How do you think bones, muscles and joints work together to move the body?
Muscles move the bones in the body, which move around axes of rotation that are provided by
the joints.
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?
I think that it means his humerous has come out of his shoulder’s ball and socket joint.
How are tendons and ligaments similar and how are they different?
Tendons and ligaments are both strands of connected tissue, but tendons connect bones to
muscle, while ligaments connect bone to bone.
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.
They are both hinge joints, but a human’s elbow has a greater angular range of motion than a
cow. A human can go from 0-180 degrees, while a cow’s ROM is much lower.
What type of joint is the hip joint? Describe the type(s) of movements this joint can perform.
The hip joint is a ball and socket joint, and it can move in a full circular motion.
Activity 4.1.2
Describe how your range of motion compares to the range of motion of those in your group.
Why might there be differences?
The sizes of people, exercise levels, gender, and many other factors can influence flexibility. For
example, my knee flexion levels was several degrees lower than the females in my group.
Which type of joint do you think allows for the greatest number of different movements?
Explain your reasoning.
The ball-and-socket joint does, because the ball will allow movement in all angular directions.
What factors influence range of motion of a joint?
The amount of cartilage, as well as physical characteristics of the person (i.e. age, size, etc.) will
influence the ROM of a joint.
Explain how a person can improve flexibility at the joints.
People can improve their flexibility through exercising and using physical therapy.
Your goniometer breaks. Describe another way you might be able to measure range of
Use your arms to estimate the angle, and then use a protractor to measure it. (Or just buy a new
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.
Your joints do knee flexion, neck extension, shoulder abduction, and finger flexion.
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
These muscles straighten the arm out.
Activity 4.2.1
Describe the differences you see in the three types of muscle tissues.
Skeletal and cardiac muscles are striated, while smooth isn’t. Skeletal has many nuclei while the
other two only have one. Smooth muscle tapers off, cardiac muscle branches off, and skeletal muscle
doesn’t branch.
What does it mean when we say a muscle contracts involuntarily? Describe one body function
that is linked to an involuntary muscle contraction.
Involuntary muscles contract without conscious effort from the brain, such as the digestive
system’s muscles.
Describe how the structural makeup of a muscle contributes to the muscle’s ability to do its
The various components of muscle being in the locations they need to be in will allow the
muscle to receive and perform the necessary actions.
Using your knowledge of tissues, what type of tissue do you think makes up the three layers
of membrane you encountered in your muscle?
Epithelial tissue.
Explain how you know which attachment of a muscle is the origin and which attachment is the
The origin stays still, but the insertion is the bone that moves.
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?
It is on the front part of her lower leg.
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?
This occurs to cause friction and create heat within the body. The heat that this produces can
get the body temperature back up to a normal level of homeostasis.
Activity 4.2.2
Look at your Maniken®. Explain to your client why you need multiple exercises to effectively
build and tone the muscles of the chest.
There are many different muscles on the chest that perform different functions. Different
movements are necessary to tone different 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.
Pull-ups will tone the pectoralis major, and swinging a baseball bat will tone the serratus
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.
The pectoralis major with origin and insertion at the ribs and arm respectively allows the arm to
move upward, and crosses the shouder joint.
Explain how the muscles pectoralis major and serratus anterior show two different ways in
which muscles are named.
The muscles can be named either by the origin or the insertion of the muscle.
Are the muscles of pectoralis major adductors or abductors? Explain.
They are adductors, because they allow the arm to move up and away from the body.
Activity 4.2.3
What did you find to be the most challenging part of independent muscle building?
Making the individual muscle fibers.
How can you determine function of a muscle simply by looking at the anatomy?
Looking at the directions of the striations will direct you to the insertion and origin.
Using your muscular system graphic organizer and your notes, identify and describe the
particular muscles that are involved in generating movement at a specific joint of the body.
The brachialis and biceps will generate movement in the elbow.
Describe how an injury to the muscle group you built on your Maniken® would impact total
body function.
An injury to the brachialis would prevent the arm from straightening properly.
Activity 4. 2.4
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.
I think the cells are expelling liquid to get a smaller size, so that they contract the muscle.
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?
Yes, because they ran out of ATP to keep the muscle contracted.
Which solution produced the greatest percent contraction of the muscles? What does this tell
you about the requirements for contraction?
.25% in salt, because the salts include necessary elements for contraction, and there is a high
concentration of ATP.
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 cardiovascular system is important because it gets the necessary components for
contraction to the muscle so that they can be used.
Activity 4.2.5
How do multiple human body systems work together to cause muscle contraction and
movement of the body?
The muscular system contracts to move the bones in the skeletal system which is made possible
because of the nutrients transported by the circulatory system.
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 is a necessary ion in muscle contraction, so drinking lots of calcium will help to build up
muscle as well.
Explain how it is that actin and myosin in the sarcomere never actually shorten and yet the
muscle as a whole does.
Actin slides along the myosin, which takes up less space, but leaves the actin and myosin the
same lengths.
How do ions and electrical charges play a role in communication with the muscle?
Ions and electrical signals from neurons deliver a signal to the muscle that the brain is telling it
to contract.
Summarize the science behind rigor mortis. Why is this state a temporary condition?
The body does not have the ATP necessary to let the muscles relax from contracting, so they
stay contracted. Eventually, lysosomal enzymes leak and allow the muscles to relax and stay relaxed.
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?
The muscle is out of ATP, and stays contracted. When the muscle receives more ATP, it will relax
again, relieving the cramp.
Activity 4.2.6
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?
This nerve stimulates the triceps.
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 at a certain point is the most exposed nerve in the body. It is very close to the
exterior of the body, so hitting it will send a sharp nerve signal throughout the arm.
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?
This nerve stimulates the brachialis.
What do you think would happen to a person’s ability to use his/her arm if the radial nerve
were damaged?
If a person injured their radial nerve severely enough, it would impair their ability to move their
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.
The central nervous system will send a signal out to the peripheral nervous system, which
stimulates the pectoralis major, the brachialis, and the triceps.
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?
The use of heavy manual labor, especially with the hands, such as construction, mining, and
farming, can all cause the injury. Risks can be lowered by wearing proper hand protection and
moderating their workload.
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
How does the structure of smooth and cardiac muscle differ from the structure of skeletal
Smooth and cardiac muscle have one nucleus per cell, while skeletal muscle has several.
Explain how each of the three types of muscle assist with moving blood around the body.
Cardiac muscle pumps the heart, smooth muscle controls the pressure in the vessels, and
skeletal muscle movements helps to move blood around more effectively.
What role do valves play in the heart?
Valves prevent the heart from pumping blood in the wrong direction.
Which structure in the heart functions as the natural pacemaker? What does this term mean?
The SA node- it originates the electrical signal at the rate which the heart needs to pump.
How does the movement of the electrical impulse relate to the contraction of the chambers of
the heart?
When the electrical impulse reaches the Purkinje fibers, it causes the myocardium to contract.
What is the difference between pulmonary circulation and systemic circulation?
Pulmonary circulation deals with blood and the lungs, while systemic deals with blood and the
rest of the body.
Thinking about function, explain why the left ventricle is much more muscular than the right
The left ventricle must pump harder to get the blood to get all the way through the rest of the
Describe the role of smooth muscle in two human body systems other than the cardiovascular
Smooth muscle causes peristalsis in the digestive system, and expels urine through the urinary
How does electrical communication in the heart compare to electrical communication in
skeletal muscles?
Skeletal muscle signals originate from the brain, while the heart signals are originated from the
heart itself.
Activity 4.3.2
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?
Artery walls are thicker because they have more muscle surrounding them, which is necessary
to keep blood at a pressure to get it to where it needs to be.
Capillaries function in gas exchange. Describe at least two ways capillary structure is related to
this function.
Capillaries have thin walls that allow for diffusion, and capillaries connect with other blood
vessels to get the blood back to the heart again.
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.
Capillaries fill up the alveoli, where oxygen is diffused into the blood.
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, because more pressure is needed to get the blood to the entire blood than just the
Describe two ways blood is helped back to the heart in veins. Mention relevant body systems.
The muscular system helps to build up pressure, and the cardiovascular system creates a
negative pressure where blood is pumped out that is filled back up.
Explain why a person who spends most of the day on his/her feet is more likely to develop
varicose veins.
Blood has to work against gravity harder and for longer which can cause the blood to back up.
Activity 4.3.3.
Why do you think the clay used to represent veins is thinner than the clay used to represent
Arteries are thicker because they have a thicker layer of muscle surrounding them.
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?
The right leg would experience necrosis, and the blood would back up in the right iliac artery,
causing even more complications.
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”?
Their bodies are used to working hard to pushing blood very hard back to the heart via muscle.
Arteries don’t need this to happen.
Why do you think arteries, veins and nerves always travel together? Provide an example that
illustrates your reasoning.
I think they all travel together because it is important that a muscle receiving blood has a nerve
to transmit instructions to it and a vein to return its waste. For example, the biceps needs the brachial
nerve to receive instructions, and the brachial artery/vein to receive and send blood.
Activity 4.3.4
Which do you think are the two, most common places to detect pulse and count the heart
rate? Why?
The radial pulse point and the carotid, because they are the easiest to feel without a Doppler or
What are some factors that can increase or decrease the heart rate and the beat you feel at
each pulse point?
A blockage or distance from the heart to a certain pulse point can prolong the time it takes to
feel a pulse.
Athletes often have a very low resting heart rate. What does this tell you about the health of
their heart? Explain.
It is very strong, because it doesn’t need to work hard to pump blood when the body is resting.
What are consequences of having a low cardiac output? How will other body systems be
The rest of the body will not get the blood and oxygen it needs, and other body systems would
have to sacrifice function because of the lack of resources.
Dehydration reduces blood volume. How would this affect cardiac output? Explain.
It would decrease it, because the heart can’t pump blood if there isn’t enough blood to pump.
Describe how each of the following could impact stroke volume.
Damage to the conduction system of the heart
It could make the ventricles not pump out the necessary amounts of blood, lowering CO.
A blockage in one of the coronary arteries
It could impact the heart’s ability to contract and pump blood, reducing CO drastically (MI).
Activity 4.3.5
What is your ABI? What does this value tell you about your risk of peripheral artery disease?
It is a measured comparison of the blood pressure in your arm to your leg, which can detect
blood flow problems in the extremities.
Explain how PAD might impact other body systems.
It could cause necrosis in the muscles which aren’t receiving enough oxygen from the blood.
How do the chemicals in smoke relate to the development of atherosclerosis?
The chemicals in smoke help plaque to form in the arteries, which stick to the vessel walls,
causing atherosclerosis.
Why do you think diabetics are also at increased risk for PAD?
The extra glucose in their blood makes it very easy for some to coagulate into a clot and get
stuck in a vessel.
Explain why untreated PAD can lead to the loss of a leg. Make sure to mention the specific
arteries of the leg.
If a leg muscle doesn’t receive the necessary oxygen from the femoral/popliteal/posterior tibeal
artery, it can die, which would make amputation required for survival.
Explain how the endocrine system and the kidneys help play a role in regulating blood
They both influence the water volume in the body, which is carried in the blood stream. This
controls the volume of the blood itself, which can affect pressure.
Activity 4.4.1
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.
Cardiovascular transports oxygen that the body gets from the respiratory to the muscles that
need it.
Our body sweats to stay cool during exercise. How does this seem to counteract the action of
the urinary system?
It expels water which 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.
Carb load- eat well and get necessary energy.
Stretch- prepare the muscles
Warm up- get oxygen going already.
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 to do glycolysis for a while, then resorts back to aerobic
respiration to use oxygen to make more ATP.
Which muscle energy system(s) is (are) used for each of the following activities? Make sure to
explain your reasoning.
The 50 meter dash
The primary energy in the blood- then lactic acid if not enough energy is provided.
A game of basketball
All three- to keep energy going throughout the whole long game.
A single football play
Aerobic- you’ve been playing football for a while and are tired.
Weight lifting
Lactic acid- you can feel your muscles burning.
Running a marathon
Aerobic- you’re running for a very long time.
Activity 4.4.2
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.
55%- jogging, you will start faster than you end if you push too hard.
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?
211%- the muscle is sending signals and working much harder to do the same grip, because it is
out of energy.
How did your mean grip strength in the last 20 seconds of the experiment compare to the 6080s interval? Explain this result.
It was increased greatly, because of the new surge of motivation.
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?”
Support- with motivation, you can push harder and pull energy from other places.
What role does the nervous system play in muscle fatigue?
The body tries to get the muscle to use less energy, because it has already expended all of its
Is the hand grip test an example of an isometric or an isotonic muscle contraction? Explain
your reasoning.
Isometric, because your body is not moving during the test.
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?
More fired in the beginning, because they all had 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, because the first two will last for the majority, but towards the end, more ATP is
opened up for use.
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
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- It provides energy, but it will crash later.
Andro- builds muscle mass, but can affect reproduction.
Some performance enhancers are only banned in specific sports. Why do you think betablockers are banned in sports such as archery or gymnastics?
It helps fine muscle skills as opposed to rough muscle skills.
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?
Self-image- it is very dangerous, and natural exercise is healthier and safer way to achieve the
same results.
“Gene doping” has recently been added to the WADA prohibited list. What do you think this
term means?
Taking medication to affect genetics.
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?
It made his body keep up the energy it needed at a much higher rate than the average human.
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.
If parents of an athlete have trained their muscles to use energy well, the athlete will have an
easier time developing. Also, genetic enhancement will help the athletes to have muscles that tire less
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.
It is using medicine to improve the body past wellness, as opposed to getting it TO wellness.