Cell Types in Nervous System

1. Neurons: Permit rapid transmission of infomation over long distances 

2. Gilial Cells: Provide structural support and maintain the extra-neuronal environment (Think GLUE) 

100 Billion neurons/ 1 Trillion Gilial Cells 

Division Based on Location or

"Anatomical Organization"

 A) Central Nervous System (CNS) 

Brain and Spinal Cord

B) Peripheral Nervous System (PNS)

Cranial nerves (12 Pairs)

Spinal Nerves (31 Pairs)

Division Based on Function

1. Sensory (Afferent) vs Motor (Efferent) 

2. Somatic vs Visceral NS

3. Parasympathetic vs  Sympathetic

Somatic Nervous System

Controls the body's VOLUNTARY and REFLEX activities thorugh SOMATIC SENSORY and SOMATIC MOTOR COMPONENTS of both CNS and PNS

Visceral (Autonomic) Nervous System

• Portion of CNS and PNS that controls INVOLUNTARY smooth muscle, cardiac muscle, and glandular tissue. 
• Has a MOTOR and AUTONOMIC SENSORY COMPONENT
• Further divided inot the Parasympathetic Division and Sympathetic division

Parasympathetic Division

NECESSARY TO SUSTAIN LIFE

slows the heart, increases peristalsis and glandular secretions

Sympathetic Division

EXPENDABLE

Effects are evident during times of stress or emergency

Fight or Flight 

Pupils dilate, heart beats faster, respiration increases, and brochioles dilate to oxygenate blood flow

Afferent Nerves

Axons that carry impulses TOWARD the CNS 

"Input to CNS" 

AKA: Sensory 

Efferent Nerves

Axons that carry impulses AWAY from CNS to muscles and glands

"Output from CNS"

AKA: Motor Nerves