Leech Neurophysiology LAB (Unit Three)

This lab simulation showed how to collect data from nerve activity using a leech.

The first image below shows the micro-manipulator used in the lab with the oscillope trace.

The next image below shows the shape of a sensory neuron with the aid of ultra-light and dye.

1. What is the electrode measuring? Electrodes record the activity of neurons. (An electrode is what someone uses to deliver a "shock" to a patient also). An electrode can be defined as a conductor to establish electrical contact with a nonmetallic substance.

2. Why use leeches in neurophysiology experiments? For this particular experiment we are using a leech because they have a simple neurological structure. This will make the structure easier to understand than that of a more complexly structured organism. Simple nervous systems follow many of the same rules that complex nervous structures follow. Therefore, understanding the simple structures first, will assist in understanding the complex structures like the human brain. Also, people generally don't feel sorry about using leeches for experiments.

3. What is the difference between a sensory and a motor neuron? A sensory neuron takes messages from a sensory receptor to the central nervous system. A motor neuron takes nerve pulses away from the central nervous system.

4. Do you think a leech experiences pain? What is pain? For the purposes of this lab, no the leech did not experience pain. (This was the intention of initially using the ethanol solution as an anesthetic). In general, however, leeches probably experience pain because they have so many neurons to send the "pain" signal to the central nervous system. Pain is initially felt in the nerves and then processed in the brain.

5. What were the two most interesting things about doing this lab? I found it interesting to be able to engage in a computerized dissection--that's a format I have not experienced before and is kind of a catch-all for avoiding errors. Also, I found the lab a lot more interesting once the dye had been applied to the cell and the detail and appearance of the cell changed.

6. Anything you found confusing or didn't like about the lab? I may have to take another Microbiology class in real life, because while the computer is convenient, I have the desire to actually take part (physically) in labs of this nature.