The Circulatory System

MS-LS1-1 All living things are made up of cells, which is the smallest unit that can be said to be alive. An organism may consist of one single cell or many different numbers and types of cells.

MS-LS1-3 Construct an explanation supported by evidence for how the body is composed of interacting systems consisting of cells, tissues, and organs working together to maintain homeostasis.

This week I was tasked with teaching an introductory lesson on the circulatory system to my seventh grade students. I remember learning about the circulatory system in middle and high school, and always having trouble remembering the different chambers and what their jobs were. In order to make the system more accessible to my students, I used areas in the classroom to represent different parts of the circulatory system. I projected a room map:

Each stick figure represents one student stationed throughout the room. They each had task cards, instructing them where to send students that arrived at their station. For example, the left ventricle card read: I am the left ventricle, a chamber in the heart. When an oxygenated red blood cell comes to me, it is my job to leave their card on oxygenated, and send the blood cell to the body." The students who weren't assigned to stations acted as blood cells, and carried index cards that said oxygenated on one side, and deoxygenated on the other. As they travelled through the system, they flipped their cards to represent whether a blood cell would be carrying oxygen at that point in the circulatory system. After the activity, students completed the following questions:

1.     What did you observe about the path of a red blood cell?

2.    What were some limitations of representing the circulatory system this way?

3.    What would happen if the lungs stopped working correctly?

4.    What do you think it means for someone to have “poor circulation”?

Reflection:

I think the activity went quite well. When working with seventh grade students, I have learned that any activity that has the students up and out of their seats will likely get noisy and rowdy, and so it's important to have very clear directions and expectations established before the activity begins. Once the activity has begun, it's so difficult to try and redirect their attention. Originally, I had planned to stop the activity several times, and randomly ask students on the path where their next stop was, and whether they were carrying oxygen or not. However, after teaching this lesson to my first class I realized that once the students got going, it wasn't effective to try and draw them back to silence, and then let them continue the activity. My cooperative teacher advised me to never try and pull students from an activity level of 10 to an activity level of 2. For example, engage them in a high energy activity and then expect them to sit down and read or write in silence. For this reason, I did not stop the activity in my other classes, but rather adjusted the questions I asked at the end, and also allowed students to complete the questions collaboratively at their tables. When a unit test was given the following week, my cooperating teacher made the bonus question based off this activity. Students had to recall the entire path of the system in order to get credit. I was extremely happy to see that most students remembered the path, and after speaking with several gained the impression that the activity helped them visualize the path when it came time to remember it for the test.