Thursday, April 3, 2008

That was Intense

Today I had the most intense animal physiology lab ever.

We we looking at cardiac contractions in frogs. So, it was a rather delicate procedure to euthanize the frog and then examine its heart without damaging it. Our GSI (grad student instructor, aka TA) added ice to slow them down, then poured lots of benzocaine (frogs absorb chemicals through their skin) to anesthetize them and overdose them, to ensure they didn't move around. Now comes the intense part.

My lab partner first stabbed a needle probe into the poor frog's brain to destroy it, so it's brain dead and can't move. It took a while because we couldn't find the easy spot to poke the probe into, and our GSI said it was difficult to find and that we should expect a "crack" sound. Well, my lab partner did that and moved the probe around. The GSI watched to make sure we did it correctly. Then I tried to stab the probe down its spine to paralyze it further that way, but I couldn't find the hole my lab partner made. So she just did that part too.

We then flipped over the frog so we could cut open its chest cavity and expose the still-beating heart. She cut off the outer skin, which was difficult because frogs are really slippery! We managed to do it with me holding the skin out with forceps and she cutting with scissors. After she cut away the outer skin, I cut the inner tissue, being careful to not cut the abdominal vein. I cut around to create a flap, and ended up having to cut off part of the jawbone. I then manged to (carefully!) cut away the pericardium, the sack that holds the heart. I must say, it's really really cool to look at its still-beating heart.

We then did our experiments and such. Every now and then, our frog would twitch one of its limbs. The first time I was startled, because it's not supposed to move at all. I've heard horror stories where people didn't properly scramble their frog's brain, and towards the end the frog started to move about with its insides falling out. My partner and I were like, "Please don't move!" throughout the entire lab.

The group sitting across from us were having twitchings of their own. The guy accidentally dropped his frog in the beginning, and his lab partner was trying to contain her nervousness and keep from shaking. They managed alright in the end.

Anyway, back to us. Towards the end of the lab, with the second to last experiment, our frog twitched in all its limbs and even moved its back a little. I nearly jumped out of my seat as I thought it was trying to move. It settled down. Earlier, I had discovered that its ovaries (frogs have huge ovaries) were sitting on top of a nerve that controlled its right arm and left leg, so if I moved the ovaries just so, both those limbs twitched. But this was different, it looked like it was actually trying to move a bit. Maybe it was a full-body twitch, but when we called our GSI over, she said it looked like more than just a muscle twitch.

I was about ready to decapitate the thing to ensure it didn't move, or at least stab the probe all the way through the head and pinning it to the bloodied foam. I didn't realize how much blood was in a frog till I saw a "halo" of blood around its body as it laid on the foam. Kind of reminded me of the cat from the movie Boondock Saints, except the frog didn't explode to a shotgun. Anyway, at the very end, the frog started its whole body twitch again then settled down. At this point, my lab partner and I were so relieved that we were done. The GSI came over and disposed of our frog for us.

Well, I'm pretty convinced that I don't want to go into surgery now. I don't like things twitching while I'm cutting into it, and I don't like the oppressive pressure of not making mistakes, as a nick in the heart would've meant restarting the lab with another frog.

That, folks, was intense.

1 comment:

B said...

I know what you mean. I had to help with brain surgery on an anesthetized rat in one lab. I was the one to drill the hole in its skull. Then we had to lesion a part of its brain to simulate Parkinson's Disease. It was an experience, to say the least.