Nervous System

Nervous System Overview

Classifying nervous system:

• Central Nervous System (CNS)

• Peripheral Nervous System (PNS)

CNS

• Brain

• Spinal Cord

Brain

• Cerebrum

  • • Lobes: frontal, parietal, temporal, occipital

• Cerebellum

  • • Vermis & two hemispheres

• Brainstem

  • • Pons, medulla & midbrain

Spinal Cord Tracts

• Anterior

  • • Spinothalamic - pain & temperature

    • Corticospinal - movement (conscious)

• Posterior

  • • Dorsal column - proprioception & vibration

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Peripheral Nervous System

43 peripheral nerves: 

• Cranial Nerves 1-12

• C1-8

• T1-12

• L1-5

• S1-5

• Coccygeal 1

By function

• Somatic (conscious)

• Autonomic (unconscious)

  • • Sympathetic (fight of flight)

    • Parasympathetic (rest & digest)

Spinal Cord Column's 

Spinothalamic Cord

• Pain and temperature

• Location: anterior

• Decussates: at level of entry

• Diseases: Brown Sequard Syndrome

Corticospinal tract

• Motor function

• Location: anterior

• Decussates in brainstem

Dorsal column

• Proprioception and vibration

• Location: posterior

• Decussates ?brainstem

Spinal artery occlusion anterior: affects spinothalamic and corticospinal tracts. 

References

1. Katzung, Bertram (1987). Basic and Clinical Pharmacology. Appleton & Lange. ISBN 9780838505533. 

Written in 2025