Teaching Tales: Blood, but no Guts

Welcome to the fourth in my series of blogs on teaching at NVCC and GMU. 

The study of genetics involved mathematics, which is never a favorite. But I knew that it was personal enough to capture student interest. In the lab, after counting kernels of corn (not an exciting task), the students progressed through analyzing the shape of their lab partner’s earlobe and the consistency of their own earwax. The tests on color blindness and the ability to taste certain chemicals provoked much discussion, but not so much as the next session. Here, they would test to discover their own blood type.

 Instruction Challenges

“Okay, please take out your lab books. It’s vital to listen carefully to what I’m saying because….Andrew, what are you doing?”

The titan-haired young man was helping himself to the items he thought he needed for the experiment. “Uh, I’m getting the stuff we need.”

“What did I tell you to do?”

Andrew was silent as I watched his color rise until his face matched his hair.

Finally, one of his classmates rescued him by shouting out. “She said to sit and listen!”

I suppressed a smile and resumed. “Read the entire lab and have all your supplies at hand before starting. Whatever you do, don’t prick your finger and then start wandering around the lab looking for supplies.” I mimed a person looking through the tray of supplies while dripping blood on the floor. After emphasizing the safety precautions, I told the class they could begin.

 Chaos Reigns

Gloria got up immediately and collected the alcohol wipe, the lancet, and a Band-Aid. She sat down and aimed the lancet at her finger.

I hurried over. “Gloria, stop! What are you doing?”

“Just going to prick myself,” she murmured.

“I can see that. Where are the slides and reagents you need for this experiment?”

“Oh…. I guess I forgot them.”

After calling for silence, I once again reminded the class to have everything ready before they began. Eventually, the bloodletting commenced. Some students had no problem sticking themselves; others found it more difficult.

“Dr. Crocker, it’s not working. I’m not getting any blood,” complained Andrew.

 “The lancets do work. You didn’t prick hard enough.”

 “Will it hurt?” asked Thiang.

 “Probably,” I answered with a smile.

 “Do I have to?”

 “Well, you can use fake blood, but then you won’t know your blood type.”

 Some students had not listened to my instructions about using their middle finger and were trying to get blood out of the back of their hand or their arm. Still others requested the artificial blood that the college provided. Chaos reigned. Then came the excitement and questions as the students began to get results.

Interpreting Results 

Demitri raised his hand. “Dr. Crocker, what do these dots on the slide mean?”

I walked over to see the slide and pointed to the board, where that result was detailed. “Well, look up there. It means that you’re blood type AB.”

“Is that good? What type is he?” Demitri asked, indicating his lab partner.

“He’s type O because there are no dots in his blood. Remember, the dots mean that the antibodies in the reagent you put on the slide are attaching to the antigens on the surface of your blood cells. That sticks them together into globs that you can see.”

Demitri puffed up his chest. “That means mine is better than his, doesn’t it?”

I shrugged. “Not really. It just means you have different antigens on your red cells. But it does mean you can accept blood from anyone. He can only donate.” 

Demitri smirked and looked around the room to be sure that everyone had heard.

Being a teacher is about watching, enjoying, educating, and repeating yourself. Especially that.