Neuroanatomy Lecture Notes

Introduction

• Playlist: Medicosis Neuroanatomy
• Goal: Understand neuroanatomy better than 95% of doctors.
• Main Divisions:
  • Central Nervous System (CNS): Brain and Spinal Cord
  • Peripheral Nervous System (PNS): All nerves outside the CNS

10 Commandments of Neuroanatomy

1. Motor vs. Sensory
   • Motor: Efferent (leaves brain)
   • Sensory: Afferent (goes to brain)
   • Anterior: Motor, Posterior: Sensory
2. CNS vs. PNS
   • CNS: Brain and spinal cord
   • PNS: All other nerves including cranial and spinal nerves
3. Brain vs. Spinal Cord
   • Brain: Forebrain, Midbrain, Hindbrain (pons, medulla, cerebellum)
   • Spinal Cord: 31 segments (cervical, thoracic, lumbar, sacral, coccygeal)
4. Somatic vs. Autonomic
   • Autonomic: Visceral/Splanchnic, includes sympathetic, parasympathetic, and enteric nervous systems
5. Myelinated vs. Unmyelinated Fibers
   • Myelinated: White matter
   • Unmyelinated: Gray matter
6. Key Terms
   • Nucleus, Ganglion, Tract, Nerve, Lemniscus, Synapse, Decussation, Commissure
7. Brain Stem Organization
   • Prosencephalon, Mesencephalon, Rhombencephalon
8. Anterior vs. Posterior Tongue
   • Different nerves and nuclei involved
9. Cranial Nerves
   • 12 pairs, different exits from brainstem
10. Definitions

• Pathway, Ipsilateral, Contralateral, Extraoceptive, Proprioceptive

Detailed Explanation

Motor vs Sensory

• Sulcus Limitans: Divides anterior (motor) from posterior (sensory)
• Examples: Biceps movement (motor), feeling feather (sensory)

CNS vs PNS

• CNS: Brain and spinal cord
• PNS: Cranial nerves, spinal nerves, and any other nerves

Brain vs Spinal Cord

• Brain: Forebrain, midbrain, hindbrain
• Spinal Cord: 31 segments

Somatic vs Autonomic

• Autonomic: Sympathetic, parasympathetic, enteric system
• Somatic: Voluntary control

Myelinated vs Unmyelinated

• Myelinated: Appears white, found in CNS
• Unmyelinated: Appears gray, found in CNS

Key Terms

• Nucleus: Collection of somas in the CNS
• Ganglion: Collection of somas in the PNS
• Tract: Collection of axons in the CNS
• Nerve: Collection of axons in the PNS

Brain Stem Organization

• Prosencephalon: Forebrain
• Mesencephalon: Midbrain
• Rhombencephalon: Hindbrain

Anterior vs Posterior Tongue

• Anterior 2/3rd: General sensation by V3, taste by cranial nerve 7
• Posterior 1/3rd: Sensation and taste by cranial nerve 9

Cranial Nerves

• Cranial Nerve 1 & 2: Come out of the midbrain
• Various cranial nerves exit at different points in the brainstem

Definitions

• Pathway: Series of neurons transmitting impulses
• Ipsilateral: Same side
• Contralateral: Opposite side

Additional Information

• Neuroectoderm: Gives rise to neural tube (CNS) and neural crest (PNS)
• Diseases: Multiple sclerosis affects myelinated fibers in the CNS

Conclusion

• Understanding these commandments and definitions is foundational for studying cranial nerves and neuroanatomy effectively.