3.3 - The Organization of The Nervous System

The Nervous System is the involuntary network of neurons that conveys electrochemical information throughout the body. It is broken up into two major subdivisions:

  • The Central Nervous System(CNS) : Composed of the brain and the spinal cord

  • The Peripheral Nervous System(PNS): Connects the CNS to our body’s organs and muscles

The PNS is then further divided:

  • The Somatic Nervous System: Set of nerves that conveys information in and out of the CNS

  • The Autonomic Nervous System: Set of nerves that causes involuntary movement(Automatic) controlled by our blood vessels, organs and glands. It is entirely not a part of our conscious.

The Autonomic Nervous System is then further divided:

  • The Sympathetic Nervous System: Set of nerves that is responsible for the actions and response we take and give when in danger

  • The Parasympathetic Nervous System: Set of nerves that brings the body back to its resting and original state.

THE CNS

Spinal Reflexes: Simple pathways of the nervous system that rapidly generate muscle contractions.

Reflex Arc - A neural pathway that control reflex actions

The PNS communicates with the CNS through nerves and it carries information to the brain and then carries out commands from the brain.

The CNS then carries out the voluntary commands to the spinal cord to the motor neurons (hence how we move our body and muscles)

The spinal cord serves as the connection between the sensory and motor neurons

The spinal cord is divided into many parts and each part is responsible for something different.

Damage to the higher levels of the spine can cause greater impairment. Individuals with damage at a particular level of the spinal cord lose sensations of touch and pain in body parts below the level of injury, as well as a loss of motor control of the muscles in the same area. Spinal injury higher up the cord usually predicts more damage such as loss of sensation and motor control over all limbs.