Nervous System Overview

Nervous System consists of:

• Central Nervous System (CNS)
  • Brain
  • Spinal cord
• Peripheral Nervous System (PNS)
  • Cranial nerves
  • Spinal nerves

\

}}Central Nervous System (CNS)}}

Brain: white matter surrounded by grey matter.

^^3 main parts of the Brain :^^

• cerebrum
• brainstem
• cerebellum

\
White matter: mainly nerve fibres with their myelin sheaths

Grey matter: mainly nerve cell bodies and branching dendrites

\
Spinal cord: gray matter surrounded by white matter.

}}Peripheral Nervous System (PNS)}}

• Somatic Nervous System
  • skeletal muscle
• Autonomic Nervous System
  • glands, smooth muscles, cardiac muscles
  • Parasympathetic Nervous System: (discrete activation)
  • Sympathetic Nervous System: (diffuse activation)

\

<<^^12 pairs of cranial nerves:^^<<

• olfactory (CN I)
• optic (CN II)
• oculomotor (CN III)
• trochlear (CN IV)
• trigeminal (CN V)
• abducent (or abducens; CN VI)
• facial (CN VII)
• vestibulocochlear (CN VIII)
• glossopharyngeal (CN IX)
• vagus (CN X)
• accessory (CN XI)
• hypoglossal (CN XII)

<<^^31 pairs of spinal nerves:^^<<

• 8 cervical nerve pairs (C1-C8)
• 12 thoracic nerve pairs (T1-T12)
• 5 lumbar nerve pairs (L1-L5)
• 5 sacral (S1-S5)
• 1 coccygeal nerve pair

<<^^Types of Neurons:^^<<

Afferent (sensory neurons): nerve fibers responsible for bringing sensory information from different parts of the body to the CNS.

• cell bodies are located just outside of the spinal cord in the dorsal root ganglion

\
Interneurons: central nodes of neural circuits, enabling communication between sensory or motor neurons and the CNS.

\
Efferent nerves: nerves that carry nerve impulses away from the CNS.

• cell bodies located in the ventral horn of the spinal cord

  

\

<<Somatic vs Autonomic Nervous System<<

\
\