Leech lab.

1. What is the electrode measuring?

The electrode is measuring the difference in electrical potential from the inside of the neuron and the outside. When the neuron is at rest its resting potential is at -65 millivolts, there are no ions moving threw the axon. When an ion signal is moving along the axon the action potential will cause the inside of the axon to have a + 45 millivolt electrical charge. The axon will go back to -65mV after depolarization to its resting potential with in 1/1000 of a second.

2. Why use leeches in neurophysiology experiments?

Leeches are chosen for biologists to measure the resting and action potential because there nervous system is easily accessible. The leech has 21 segmental ganglia and each is containing 175 pairs of neurons. With the leeches small size and large neurons they are the best subjects to use for neurobiologists.

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

A sensory neuron takes a signal from a nerve in your body to the spinal cord and depending on the nerve impulse to the brain. When the spinal cord and brain receive the impulse from the sensory neurons the signal is processed and another signal is sent to the motor neuron which then activates a muscle for a reaction to the nerve stimuli this is called somatic reaction (you control what the body does).

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

Yes, if the leech was alive as you were cutting it open I think it would. I have not done the research on the leech but if they respond to touch and stimuli then they have nerves that send signals to there brain threw sensory neurons. If there version of a central nervous system can respond to stimuli then it would make sense that pain would also be a function of the nerves.5. What were the two most interesting things about doing this lab?
I thought the lab was very interesting and the fact that to actually perform the lab you would need a variety of specialized equipment. I think that is the nice thing about doing online labs being able to see more in depth procedures which would be harder to do in real life. The second thing I found very interesting was the image you get when you ad the colored dye and use the UV switch. After viewing the atlas it was cool to see the different neurons you could identify.

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

No!