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4.4.1 The Body's Response to Exercise

Last updated over 4 years ago
29 questions
Note from the author:
Part of the PLTW curriculum, students learn about how exercise is going to effect the body and apply it to a situation of a girl running a mile in a track meet.
Use the website embedded below to answer the questions for your group. You should take notes on how exercise effects the body. There are multiple pages on the website, so you should click through the pages to learn more about what is happening when we exercise!

At The Start

Mary is stretched and ready to go. She has been a member of the high school track team for the past three years, but this is the first time she is competing in the mile. As she sits with her coach before the race, she tries to visualize each step around the track. She is well rested, well hydrated, and overall pretty calm. Her heart rate monitor reads a steady 68 beats/minute. It is 85 degrees outside, but in the shade her body temp remains a steady 98.6 degrees.
As she approaches the start, she takes a look at her competition and does one last stretch of her calves. She gets into position and waits for the starting gun. Her heart rate is now up to 85 beats/minute, and her mouth feels incredibly dry. Mary can feel the tension in the air as the competitors wait for their signal.
1

We have talked about the central and peripheral nervous systems. We know that the peripheral nerovus system relays signals to and from the spinal cord. But this system is divided yet again. What are the two main divisions of the peripheral nervous system? How do these systems relate to the three types of muscle?

1

Why is the sympathetic division of the autonomic nervous system active just before the race?

1

How does the nervous system influence other body systems at the start of the race?

1

What is happening to the digestive and urinary systems at the start of the race? Why?

1

What is happening to Mary's blood glucose levels right before the race? Relate this change to energy and ATP.

1

Why does her mouth feel dry?

One Minute into the Race

The gun sounds and they are off. Mary sprints off the line. She knows the pace will soon come down, so she really pushes herself in this first minute. Her heart rate is now 180 beats/minute. Her muscles are feeling that all-too-familiar burn, and her breathing feels fast and forced. Sweat starts to bead on her forehead. If she can keep ahead of the pack, she will soon be able to settle into her race pace.
1

Running at a sprint puts new demands on Mary's body. What are these demands and how are they being met?

1

Why do Mary's muscles feel like they are burning? Relate this burn to information about ATP production.

1

Why does Mary's respiratory rate increase as she starts to run? Provide two reasons.

1

How does Mary's increase in heart rate relate to cardiac output?

1

How does the nervous system interact with the cardiovascular and respiratory systems to increase the blood flow to the muscles?

Halfway through the Race

Now at a comfortable pace, Mary feels her heart relax a bit and she is not struggling as hard for breath. Sweat runs down her face. The middle of the race comes and goes, and she mentally prepares herself for the push ahead. She’s currently in second place, but she is waiting to make her move.
1

Why does Mary's body temperature start to increase? What is one of the main by-products of muscle contraction? (Think about why you might shiver!)

1

How does sweat work for the body?

1

What part of the brain helps stimulate the sweat glands in the skin?

1

How does the urinary system deal with the loss of water through sweat? What did Mary do before the race to try and alleviate this conflict?

1

How does the urinary system deal with the loss of water through sweat? What did Mary do before the race to try and alleviate this conflict?

1

Why does Mary feel a bit more comfortable during the middle of the race? Where is she drawing her energy at this point?

At the Finish

As she heads into the final lap, Mary picks up the pace. Her speed builds as she turns the last corner. Her heart rate is now over 200 beats/minute and she tries to pair her quick breaths with the sound of her shoes on the ground. She can hear her coach in her head. She lengthens her stride and pushes her muscles to the limit. Mary and her competitor are neck and neck—there is no slowing down at this point. One last push and Mary propels herself into first place. She crosses the finish line and slows down, but she keeps moving. She can feel her heart beating in her chest. Her respiratory rate is extremely high, but she still feels like she is not getting enough air. Sweat is pouring out of every pore. Her body temperature is now 101 degrees. She feels a little dizzy, but she keeps moving. She can hear her family and her team cheering in the background.
1

Why does Mary feel dizzy at the end of the race?

1

Why is Mary's heart rate and breathe rate so high even though she has stopped moving?

1

Why did Mary only sip water at the end of the race? What could happen if she drank water too fast?

Ten Minutes after the Race

Ten minutes later, Mary is starting to feel much better. Her heart rate is down to 80 beats/minute, and she is having no trouble breathing. Her body temperature is lower, but still a bit above normal. She is extremely thirst,y and she sips water as she stretches. Mary rubs her sore muscles and makes her way to the locker room. She weighs herself when she gets there and finds that she has lost two pounds. Starting to feel hungry, Mary gets ready to meet her family for a celebratory meal.
1

What division of the autonomic nervous system is at work now? How does this division impact Mary's other body systems?

1

Explain how Mary could have lost four pounds in such a short period.

1

How will Mary's actions and her endocrine system work to bring her body back into water balance?

1

Why do Mary's muscles still feel so sore?

1

Work with your group to come up with the "big picture" of what is happening during exercise. Share your research with your group and generate a timeline of what is happening to your body during exercise. Create a timeline using Google Draw or by using the drawing tools built into GoFormative.

Conclusion Questions

1

Provide at least two examples of the opposite effects of the sympathetic and parasympathetic divisons of the nervous system.

1

Explain how the respiratory and cardiovascular systems work together to meet the demands of the working muscle.

1

Our body sweats to stay cool during exercise. How does this seem to counteract the action of the urinary system?

1

Which muscle energy system(s) is (are) used for each of the following activities? Explain your reasoning.
  • The 100-meter dash
  • A 5-mile run
  • A game of basketball
  • A game of football
  • Weight lifting
  • Running a marathon