1. Divisions of the Nervous System

2. Central Nervous System (CNS)
The central nervous system consists of the brain and the spinal cord.
The brain and spinal cord are made up of mostly interneurons.
The spinal cord: a thick column of nerves that connects the brain to most of the nerves in the peripheral nervous system.
The brain: three regions, the cerebrum, cerebellum, and brainstem.

3. Meninges: three layers of protective tissue (dura mater, arachnoid mater, and pia mater) in the brain and spinal cord
Cerebral Spinal Fluid: fluid found in the meninges that cushions, provides nourishment and removes waste from the brain and spinal cord

4. Paralysis
The loss of muscle function for one or more muscles. Most paralysis is due to injury of the nervous system, in particular, the spinal cord.

5. Consists of sensory and motor neurons
Peripheral Nervous System (PNS)
Consists of sensory and motor neurons
Two divisions  sensory division and motor division

6. The Sensory Division Consists of sensory neurons
Has two sets of neurons: one set brings internal stimuli to the CNS and the other brings external stimuli to the CNS

7. The Motor Division Consists of motor neurons
Somatic nervous system: motor neurons in this division carry out voluntary movements, or things you choose to do.
Autonomic nervous system: motor neurons in this division carry out involuntary actions such as digestion, saliva production, glucose release, pupil dilation

8. THE BRAIN IS NOT INVOLVED IN A REFLEX ARC!
An unconscious/involuntary response to a stimulus such as pupil dilation, knee- jerk reaction. The signal bypasses the brain.
Reflex Arc
The sensory neuron brings the impulse to the interneuron in the spinal cord and the impulse goes right to the motor neuron.
THE BRAIN IS NOT INVOLVED IN A REFLEX ARC!