Leech Lab

Finding the ganglion




The dye has been injected




Identifying the neuron

1. What is the electrode measuring?

The electrode is measuring the voltage of the neuron.

2. Why use leeches in neurophysiology experiments?

Leeches are popular subjects with neurobiologists because they have relatively few neurons (about 175 pairs) and those neurons are fairly easy to get to. Also, it seem that leeches do not elicit the sympathy that other, cuter animals subjects do.

3. What is the difference between a sensory and a motor neuron?

A sensory neuron carries nerve impulses to the brain, while motor neurons takes nerve impulses or commands to the effectors in the skeletal muscles.

4. Do you think a leech experiences pain? What is pain?

I think leeches can experience pain, they do have a nervous system. The leech was anesthetized prior to the procedure so I don't think it experienced pain in this case. Pain is caused when sensory receptors in the area send nerve impulses to the CNS. Motor neurons in turn send commands to effectors telling our bodies what to do in response. An example is touching a hot surface and reflexively withdrawing our hand.

5. What were the two most interesting things about doing this lab?

It was interesting to me that although the leech is a relatively simple creature, dissecting it is still quite complicated. I also find it interesting that there are some basic similarities between the leech's nervous system and our, like the nerve cord for example.

6. Anything you found confusing or didn't like about the lab?

I did not find anything particularly confusing, but i do not think I could dissect an real leech on my own.