The Central Nervous System

Introduction: Above is a picture previous seen, depicting the CNS from http://www.faqs.org. Now let us take a look at the "power house" of the body. We are going to take a look at the spinal cord and the brain. The brain is huge, obviously, and unfortunately, to go much deeper would require enrolling in a psychology course. Here we are going to go over brief information in regards to different parts and their functions.

The Spinal Cord

From http://www.fithealthsite.com is a picture of the spinal cord. It also shows the brain, so technically, it is also showing the central nervous system.

~Functions:

1. Communication between brain and the peripheral nerves

2. Brain initiates voluntary control over limbs

Motor impulses move down spinal cord out to limbs

*If spinal cord is severed, motor impulses can’t move down

And out, so then one suffers loss of sensation and

Voluntary control (paralysis)

*If severed in thoracic region, lower body and legs paralyized

Aka paraplegia

*If severed in neck region, all four limbs are usually affected

Aka quadriplegia

3. Reflex Actions

*Center for thousands of reflex arcs

* Refer back to A Simple Example

Here is a picture that is another simple example. This picture was found at http://tutrin.com/reflex.gif. It highlights the part where the spinal cord is directly affected and used.

The Brain

This picture is from http://www.morphonix.com.

*The Brain

~Cerebrum: largest part of the brain and the last to receive sensory input and

And carry out processing before giving out commands to

Voluntary responses

~Cerebral Hemispheres: two halves of the brains split by the longitudinal fissure,

But connected by “a bridge of tracts within the corpus callosum.” (pg 256)

Below are the "lobes" or regions of the brain. This was found at http://www.science.ca.

~4 Lobes

1. Frontal: Primary Motor

2. Parietal: Primary Somatosensory

3. Temporal: Primary Auditory

4. Occipital: Primary Vision

~Cerebral Cortex: “Region of the brain that accounts for sensation, voluntary

Movement, and all the thought processes we associate with

Consciousness” (pg 257).

~Cerebellum: receives sensory input about position of body and gets motor

Output from the cerebral cortex about where the body parts should be

Conclusion: There you have it. A brief, but thorough deeper look into the central nervous system. Another great resource, for almost anything, is, of course, "The Magic School Bus" series. They are very simple explanations, but it does a great job of giving the gist of things. We know that the central nervous system is an integral part (it does include the brain) but it cannot do it alone. The other part of the nervous system is our peripheral nervous system, that you will see is split even further.