Central Nervous System

The central nervous system is made up of the brain and the spinal cord. The central nervous system is where sensory information is received and motor control is initiated.

The spinal cord extends from the base of the brain to what we call our tail bone. The role of the spinal cord is to provide a means of communication between the brain and our peripheral nerves. When the brain initiates involuntarily control over our limbs, motor impulses pass down the descending tracts in the spinal cord and out to our muscles by way of motor fibers. That is why when someone severs their spinal cord it results in paralysis.

The brain contains more than 100 billion neurons. The brain contains four lobes: frontal lobe, parietal lobe, temporal lobe and the occipital lobe.

The frontal lobe is where the primary motor function takes place, also plays a part in impulse control, judgement, parts of speech and emotions just to name a few. People with injury to their frontal lobe may suffer from paralysis, the inability to complete a sequence of complex movements, have trouble focusing, mood swings, difficulty problem solving and the inability to verbally express themselves.

The parietal lobe associated with movement, orientation, recognition, perception of stimuli. An injurt to this section could cause a person to have trouble drawing, naming an object, trouble with math, lack of awareness with certain body parts, inability to focus and trouble with hand/eye coordination.

The temporal lobes functions are hearing, speech, memory and emotional responsiveness. Injury to this lobe could result in difficulty in recognizing faces, trouble understanding spoken words, agressive behavior, and short term memory loss just to name a few.

Lastly, we have the occipital lobe. The occipital lobe is the visual processing center. Injury to this lobe could result in vision difficulty, hallucinations, trouble distinquishing colors, and difficulty with reading and writing.

What is a neuron?

A neuron is a nerve cell that characteristically has three parts: dendrites, cell body, and axon. (Human Biology, Sylvia Mader 10e) Neurons send messages electrochemically, meaning that chemicals cause an electrical impulse.

The dendrites are the part of the neuron that receive and carry the impulse to the cell body.

The cell body contains the nucleus and the dendrite and axon extend from this.

The axon carries impulse away from the cell body to the dendrite.

All neurons have the same basic structure. There are three total neurons they are sensory neurons, interneurons, and motor neurons.

Sensory neurons takes nerve impulses from a sensory receptor to the central nervous sysem. They are what detect changes in the environment.

Interneurons are located in the central nervous system. They receive input from the sensory neuron and also from other interneurons in the central nervous system.

Motor neurons are what takes nerve impulses away for the central nervous sytem to a muscle or gland.

Nerve impulse is what conveys the information within the nervous system. The conduction of an nerve impulse is all or nothing. The intensity of a message is determined by how many nerve impulses are generated in a specific time span.

Unit 3 section 1

In this section we learned about the nervous system. And what role it plays in our body. Some of the key things that we learned about and I will be briefly reviewing are:
* the structure of a neuron
* the central nervous system
* the peripheral nervous system
* the autonomic system
* how drugs affect the nervous system
* sensory receptors

Leech Lab

1. What is the electrode measuring?
The electrode measure voltage. While not shown in this lab you have to have an electrode in the solution to get a starting point. You then use the microelectrode to measure the potential difference across the neurons membrane.

2. Why use leeches in neurophysiology experiments?
Leeches are a favorite of scientists to use because they have a small number of neurons that are relatively large.

3. What is the difference between a sensory and a motor neuron?
A sensory neuron is responsible for transmitting information from external stimuli to the central nervous system. While a motor neuron is located in the central nervous system and controls muscles.

4. Do you think a leech experiences pain? What is pain?
I do believe that the leech experiences pain. As we saw with this lab certain nerves were responding to certain stimulations.
Pain is different for different people but, I would describe pain as a feeling of discomfort.

5. What were the two most interesting things about doing this lab?
I found it interesting that different cells felt different stimulations. I would have thought a nerve is a nerve and would feel it all. I also found using the dye to follow the path of the nerve interesting.

6. Anything you found confusing or didn't like about the lab?
I liked this whole lab...it took me a few times to find the T cell, but I was finally able to locate all the different cells.

self evaluation

At what moment during this unit did you feel most engaged with the course?


At what moment unit did you feel most distanced from the course? Probably during the lab when we were figuring out all our body rates.


What action that anyone (teacher or student) took during this unit that find most affirming and helpful? Sending out the emails encouraging us to keep up the good work.


What action that anyone (teacher or student) took during this unit did you find most puzzling or confusing? I didn't find anything puzzling or confusing that anyone did.


What about this unit surprised you the most? (This could be something about your own reactions to the course, something that someone did, or anything else that occurs to you.) I was surprised that I liked learning about the nutrition the most as that is one of my weaknesses.

self evaluation

1. What were the three aspects of the assignments I've submitted that I am most proud of?

For me the tests were probably where I did better on and the compendium reviews.

2. What two aspects of my submitted assignments do I believe could have used some improvement? I think that my lab could have been better as well as my essay.

3. What do I believe my overall grade should be for this unit? I believe my grade should be about a C and no lower because I did try my best.

4. How could I perform better in the next unit?

Making sure that I understand all the projects and maybe looking at other students to get an idea of how they did something.