Lesson 1: Movement
What We're Going to Learn and Why it Matters
So, by now, you've got a good sense of how muscles work in opposing pairs to pull on bones via tendons. That knowledge has been around for centuries.
But it's a lot harder to figure out HOW muscles do their contracting. Muscle tissue is the only tissue that life has ever "invented" that can lead to the kind of quick, large-scale movement that characterizes animals. Sure, plants can bend toward the light if you give them a couple of hours. Protists can flap their cilia or whip their flagella around. Slime molds . . . well, OK, I'll give you the slime molds . . . but they're the exceptions to everything. But even a slime molds can't fly or do backflips or dance the stanky leg. A microscopic look at skeletal muscles reveals that they are built of long, thin cells. These cells are organized into bundles within bundles within bundles. And there's something funny about these cells. They're striped! Take a look at the micrograph below. Do those funny stripes have something to do with the peculiar talent of muscle cells? Physiologists thought so, but they had no way to find out what until the 1950s. Then, new technologies like X-ray diffraction, electron microscopy, and interference microscopy allowed a closer look than scientists had ever had before. What scientists saw led them to a model of muscular contraction that was complicated, beautiful, and elegant. By the end of this lesson, you'll be a be able to use the sliding filament model to describe how muscles contract at the cellular and molecular level. |
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Predict
(3:00 minutes)
Let's start with something simple like the flexion and extension of your elbow. How do you think that happens?
Answer on Google Classroom.
Let's start with something simple like the flexion and extension of your elbow. How do you think that happens?
Answer on Google Classroom.
Introducing a Model of Muscular Action
You live in a time when information about all kinds of scientific topics is easy to come by. But imagine if you weren't. Imagine you live in a time before anyone knew much about the working of the human body. There is no internet. There are few books to go to. The books that are out there are as full of hearsay and superstition as they are of information.
Turn and Talk: How would you go about answering questions about how the human body moves.
Here's a model of muscular movement that we'll use in today's lesson. Let's look at it together.
Turn and Talk: How would you go about answering questions about how the human body moves.
Here's a model of muscular movement that we'll use in today's lesson. Let's look at it together.
Small Group Investigation
(40:00 minutes)
We're going to start with a look at the gross anatomy of the arm to help us answer this question. Gross anatomy is not necessarily disgusting. (Though I'm not ruling that out.) Gross, in this sense, means macroscopic--stuff that we can see without magnification. Use the images attached to Google classroom as your only source to apply our model of muscle action to an elbow that flexes and extends. Make a well-labeled poster that addresses all the aspects of our model. Attach a photo to the assignment on Google Classroom.
We're going to start with a look at the gross anatomy of the arm to help us answer this question. Gross anatomy is not necessarily disgusting. (Though I'm not ruling that out.) Gross, in this sense, means macroscopic--stuff that we can see without magnification. Use the images attached to Google classroom as your only source to apply our model of muscle action to an elbow that flexes and extends. Make a well-labeled poster that addresses all the aspects of our model. Attach a photo to the assignment on Google Classroom.
Whole Group Consensus Discussion
(10:00 minutes)
Individual Summary
(4:00 minutes)
Take a moment to post individually on Google classroom and reflect on your learning in this lesson. You may do this in several ways.
Take a moment to post individually on Google classroom and reflect on your learning in this lesson. You may do this in several ways.
- Summarize what you've learned about gross muscular action in three or four key ideas.
- Speak briefly about how this learning has changed your understanding of how we move.
- Reflect on how this knowledge might be important.
- List questions or confusions about this that still remain.
- Any combination of the above.