On February 5, a very official-looking, white-coated Mr. Brian Theroux guided his 9th grade Biology students through the perfect science lesson as we approach Valentine's Day: a hands-on dissection of a sheep's heart that offered our young men an opportunity to explore the intricacies of cardiovascular anatomy. Most students seemed far more curious than squeamish.
But first, let's get those aprons and gloves on, men...
The dissection process began with a quick classroom lesson about the process, then the group of fifteen students moved on to the lab where, working in groups of three at fully-equipped dissection trays, the lesson began.
After removing the heart from a preservative-filled sack (older students among us surely recall that distinctively acrid aroma) the first step was careful observation, then testing blood flow through the heart using colored pencils and water to simulate the path of blood from pulmonary vein to the aorta, and from the vena cava to the pulmonary artery.
Next came the actual dissection which took a bit of aggressive sawing -- perhaps the biggest surprise was how densely fibrous the cardiac muscle is -- to reveal the internal anatomy of the organ. After carefully cutting open the sheep's heart, lab partners examined the organ's chambers, valves, and blood vessels that guide the circulatory system++++.
A sheep's heart is a close approximation in structure and size to a human heart, so the lesson also was an introduction to comparative anatomy. Theroux reports that later this year the young men will dissect a variety of species -- turtle, rat, baby pig and more -- in a single lab to continue this interesting comparative anatomy lesson.
Today's practical experience fostered a better understanding of physiological concepts, such as cardiac function and blood circulation. Overall, this was a good introduction to the miraculous simplicity of the pumping heart that beats inside each one of us.