“Good morning, everyone!” greeted Upper School science teacher Sallie Mathis as her Class 9 Biology students entered the 8th floor lab.
As they took their seats, the students prepared themselves for what promised to be an enthralling lesson. As part of their over-arching circulatory systems unit, they had, in previous classes, identified components of the system and learned the route of blood through the heart and body. Today, they would be engaging in a hands-on lab, dissecting a sheep’s heart to deepen their understanding of its intricate anatomy.
“I want you to focus on the exploration piece,” Ms. Mathis said, encouraging students to take initiative. “If you think something is connected, cut it open and find out!”
Before they could dive into the lab, the scientists needed to review a very important component: Safety.
“You absolutely need gloves and goggles. Do not come over to receive a heart until you’re prepared,” Ms. Mathis said, noting, too, that students must also wash their hands before and after the dissection. “You’ll also be using a scalpel,” she continued, “They are extremely sharp – please be very careful.”
Equipped with their safety gear and two resources – a procedure/protocol for dissection and a diagram of the heart with labels – the students, full of excitement and, seemingly, no squeamishness, got straight to work.
Each pair placed a heart in a silver tray and brought a scalpel, toothpick and tweezers to their lab table. With wide-eyed awe, they poked and prodded at the exposed muscle before them. “Look at what we just revealed!” exclaimed an enthusiastic duo who discovered the pulmonary trunk. Others commented that the dissection was “cool” and “fun.”
“Try to find certain anatomical pieces from the diagram,” advised Ms. Mathis.
The students slowly began to identify chambers, ventricles and valves. One student observed that hearts are about the size of a clenched fist. Another noticed the septum, a feature that separates the right side of the heart from the left – just like the one in your nose.
Once their lab time came to an end, the students safely disposed of all their tools, sanitized the tables and vigorously washed their hands. Once finished, they reclaimed their seat at a desk to engage in a brief class discussion.
“What was one thing you discovered or learned today?” Ms. Mathis prompted.
One student shared that she found the aorta, which she knew indicated the top of the heart and, from there, was able to find other portions. Another said she discovered ventricles behind tendons. A third noted she found it interesting that once the heart was cut in half, it wasn’t a 50-50 split, and that the left side was larger.
One scholar reported, “I saw the little tendons that help the heart pump blood which was really cool,” and remarked that she could feel how strong they were, despite their small size, when she tried to cut through them.
In addition to the heart, students have studied blood vessels, arteries, capillaries and veins. Following this lesson, they will examine blood types to round out this robust unit.
