UNIT 3- LEECH LAB

Leech Neurophysiology Lab

This lab involved the dissection of a leech and then observing the nervous system under the microscope. It was interesting to start out with a leech on a tray, following the commands to dissect it, and then observing the cell under the microscope. I have had numerous encounters of these nasty, slimy worms stuck to me when I was little! Yuck! Below I will answer questions relating to the lab section. Hopefully by looking at the pictures you will have a general idea of the lab process it to look at the neurons of a leech under a microscope.





This picture shows the manipulator screen with the oscillope trace findings (purple boxes). It shows the chemical and physical parts of the neuron. Leeches consist of a brain, ganglia, and nerve cord. Looking at different cells by using the feather, probe and forceps to help move the tissue around to get a better view of the neuron cell and to check the response.








This picture shows using the dye injection and the ultra violet light to better visualize the neuron. Once the image was on the screen, it asked to identify the cell. To the right of the picture is a list of different cell types and the tools (feather, probe, forceps) used to get the image of the neuron. This particular cell is a dyed N cell used with forceps.


1. What is the electrode measuring? Electrodes record the activities that occur within the neuron. A good example of this is during defibulation. The electrodes placed on the individual sends an electrical shock to the heart, in hopes that it will beat again.

2. Why use leeches in neurophysiology experiments? Leeches have large neurons which makes it easier to experiment with. The background information in this lab also states that leeches have about 175 pairs of neurons.


3. What is the difference between sensory and motor neurons? Sensory neurons have nerve cells that relay external information to the CNS. This all depends on the organism. Motor Neuron are neurons found in the CNS with axons on the outside, giving control to muscles.

4. Do you think a leech experiences pain? What is pain? I would think leeches would feel pain. Everyone has a different pain tolerance and opinion of what pain is. To me pain is an injury that has an unbearable sensation(sharp, excruciating, throbbing).

5. What were the 2 most interesting things about doing this lab? Just being able to view a whole leech, using the tools to dissect, and observing the neuron under the microscope was quite interesting. It was also neat that it provided extra information and history on leeches as we clicked around trying to find a cell.

6. Anything you found confusing or didn't like about this lab? Trying to explain the pictures of what I did with the lab was hard. It's one of those things that you have to actually go through the process to know what it is I am talking about.


In conclusion this lab shows that inside of a slimy, disgusting leech are numerous neurons. Although it is hard to see the process of the lab, it mainly consisted of dissecting the leech, finding a cell, trying different tools to move back the tissue, using an ultra-violet light and a dye to get the finished product: a leech neuron. A leech consists of a brain, ganglia, and nerve cord which makes them an interesting lab animal to experiment on. Leeches are now being used for numerous medical reasons. A leech bite is used as an anticoagulant and vasodialtor, which comes from its saliva. This lab was able to show the amazing view of a neuron, found in a leech.