As part of the 7th graders current unit on the heart and circulatory system, we had a current parent come in (Dr. C – a Cardiac Electrophysiologist) to give a presentation to the whole 7th grade about the heart, pacemakers, heart health, and perform a dissection on the sheep heart. We set up a camera and projected it onto a large screen so that all the students could see to the dissection from anywhere in the room. Dr. C gave a wonderful presentation and we were lucky to have him share his experience and knowledge with us!
The next day, students had an opportunity to dissect a sheep heart and examine the structure and function of the heart up close. The students used sheep hearts that were frozen and then thawed prior to use instead of using preserved specimens. In my opinion, this provides a more realistic experience and is easier for the students to dissect. Since the heart was fresh, the cardiac muscle, arteries, valves, and veins were much easier to see and handle this way.
lab coat/apron/old shirt
pre-made labels using sticky notes or masking tape
Which way to the heart? Students learned about Heart Anatomy and Blood Flow (blog entry)
Pickle Dissection – Students learned how to use dissection tools (blog entry)
This is an updated version of an activity I have used with my 7th graders in the past. To get a true understanding of how blood circulates through their body, and to review the parts of the heart, I have the students sort the cards and place them in the right order starting and ending with the right atrium.
Students work in pairs placing the cards into the correct sequence on their desks. When they are ready to have their work checked, I start at the right atrium and go until I find a card out of place, then I stop and have them figure out what should come next and I’ll come back to check later. It will take several tries until they complete it correctly. When they are done, students can quiz each other using the cards or they can try the activity individually and have their partner check their work. Students can also use the Google Slides to review at home or print out a color set for their own use.
Heart Coloring Page – this is a great diagram of the heart. We color this together step-by-step in class when introducing the parts of the heart. Students can use pink and blue highlighters or colored pencils. (link)
We use blue only to distinguish deoxygenated blood from oxygenated blood in diagrams
I have the students hold the diagram in front of them and face each other so that they can see the right side of the heart matches their right side, but when the diagram is on their desk, the right side of the heart is on their left.
When we are done coloring, using their pointer finger, students trace the path of blood through the heart as I say each part in the correct sequence
This video has a simplified explanation, but is incorrect in stating that deoxygenation blood cells look blue, which adds to the common misconception students have about their blood being blue when it is in their veins.
You can ask them if they ever had their blood drawn, it doesn’t come out blue, it comes out maroon-ish or dark-red instead of bright red like when they get get a paper cut or scrape their knee.
Horseshoe Crabs have blue blood: Nature Videolink updated 3/8/18
Before starting the activity, have the students practice finding their pulses and counting. I find that they are more likely to feel their pulse on their neck (carotid) near their jaw.
For the lab, students will first get a baseline for their heart rate. They average their sitting and standing pulse and use that pulse to compare the other activities to. Each student will then make their own hypothesis, which activity will have the highest pulse? The lowest pulse?
Class management tip: We did each step of the lab together, and I kept time using the online stopwatch on the screen. That way, we were all jogging in place or doing jumping jacks at the same time.
Students recorded their data on to the excel spreadsheet and I collected and entered data onto my copy. Each student shared their data, one at a time, while the rest of us entered it. If you have google docs, you can add all data to the same shared Google Sheets.
The template that I have uploaded will automatically do the calculations for you and create a bar graph. You can turn that feature off, by deleting the formulas and graph, if you want students to learn how to use the formula for averages and create charts.
If you are having any issues with the excel sheet, or want to modify it, please reach out to your technology specialist for assistance.
For related lesson plans, please visit my Life Science page.