Welcome to this lesson today on the central and peripheral nervous system. Today, you will be learning the structure and function of both the central and peripheral nervous systems. Specifically, you will look at:
So the central nervous system, sometimes abbreviated CNS, is composed of the brain and the spinal cord, and contains all of the inner neurons of the nervous system. So all the inner neurons of the nervous system can be found within the central nervous system.
The central nervous system contains both afferent and efferent nerves. So afferent nerves are carrying information towards the central nervous system, and efferent nerves are carrying information away from the central nervous system.
The other division of the nervous system is the peripheral nervous system, sometimes abbreviated PNS. So the peripheral nervous system is composed of 31 pairs of spinal nerves and 12 pairs of cranial nerves.
So the peripheral nervous system is divided into two divisions:
1.The Somatic Division
So somatic nerves are nerves that carry signals to the head, the trunk, and the limbs. So the effectors for somatic nerves would be skeletal muscle, for example.
2.The Autonomic Division.
Autonomic nerves are nerves that carry signals to your internal organs. So the effectors in this case, then, would be like smooth muscles or glands.
From there, we can actually break the autonomic division into two more divisions:
So sympathetic nerves are nerves that dominate at times of danger, stress, excitement. And basically, they increase the force and the rate of your heartbeat, increase your blood pressure, and increase your breathing. So what this does is it primes the body to respond to an emergency.
Parasympathetic nerves are nerves that dominate during quiet, low-stress situations. So basically, what they do is slow the body down and divert energy to things like digestion or other housekeeping items.
Sympathetic and parasympathetic nerves are actually antagonistic to one another. So the acts of one are opposite of the acts of the other.
If you take a look at a diagram above, the nervous system is broken down into two divisions: the central nervous system and the peripheral nervous system. The peripheral nervous system is in green. So you have the cranial nerves, and then you also have the spinal nerves. Ganglia, which are clusters of neurons, can also be found in the peripheral nervous system.
Then, the peripheral nervous system can be broken down even farther into the autonomic division and the somatic division. And the autonomic division can be broken down even further into sympathetic and parasympathetic nerves.
So this just gives you kind of more of a visual of how the nervous system can be broken down into the different divisions and different nerves. So this lesson has been an overview on the central and peripheral nervous systems.
Keep up the learning and have a great day!
Source: THIS WORK IS ADAPTED FROM SOPHIA AUTHOR AMANDA SODERLIND
Motor neurons that innervate deeper organs and regulate unconscious organ activity
Division of the nervous system that consists of the brain and spinal cord, is the processing center of the body, and contains interneurons
A division of the autonomic nerves which allow the body to recover from stressful situations by slowing down physiological activity
Division of the nervous system that sends signals to and from the central nervous system and contains sensory and motor neurons
Motor nerves that innervate skin and muscle
A division of the autonomic nerves which prepare the body for stressful situations by increasing physiological activity