Introduction to the Neurologic System

Key Topics Covered:

1. Anatomy of the Neurologic System
2. Basic Functions of Neurons
3. Neurological Assessment

1. Anatomy of the Neurologic System

Subsections:

• Central Nervous System (CNS)

  • Consists of the brain and spinal cord.
  • CNS is the control center, receiving, interpreting, and responding to stimuli.
  • CNS tissue does not regenerate if damaged.

• Peripheral Nervous System (PNS)

  • Composed of 12 cranial nerve pairs and 31 spinal nerve pairs.
  • Connects the CNS to the rest of the body.
  • PNS nerves can regenerate unless the damage is too severe or near the spinal cord.

Spinal Column and Protection

• Spinal Column: 33 vertebrae (7 cervical, 12 thoracic, 5 lumbar, 5 sacral fused, 4 coccyx fused).
• Protection:
  • Meninges: 3 layers (Dura mater, Arachnoid, Pia mater)
  • Cerebral Spinal Fluid (CSF):
    • Cushions brain and spinal cord.
    • Circulates waste and nutrients.

2. Basic Functions of Neurons

Neuron Types

• Afferent Neurons: Bring impulses towards the CNS.
• Efferent Neurons: Carry impulses away from the CNS.
  • Autonomic Neurons: Control involuntary responses.
  • Somatic Neurons: Control voluntary movements.

Nerve Impulse Transmission

• Synapse: Gap between neurons.
• Neurotransmitters:
  • Excitatory: e.g., Dopamine, Serotonin.
  • Inhibitory: e.g., GABA.
• Acetylcholine: Key neurotransmitter at neuromuscular junctions.
• Enzymes: Acetylcholinesterase breaks down acetylcholine.

3. Neurological Assessment

Basic Neuro Assessment

• Level of Consciousness: Alertness, orientation.
• Speech Patterns: Clarity, hesitancy.
• Facial Symmetry: Tongue positioning.
• Pupil Assessment: Size, reactivity.
• Strength Assessment: Grip strength, push and pull.
• Sensation: Check for numbness or tingling.

Advanced Assessment Tools

• Dermatomes: Relationship between body areas and spinal nerves.
• Cranial Nerves: Full assessment done if neurologic concerns are present.
• Glasgow Coma Scale (GCS):
  • Eye opening (4 points), verbal response (5 points), motor response (6 points).
  • Scores: ≤7 often indicates coma.

Reflexes and Posturing

• Babinski Reflex:
  • Negative normal in adults; positive indicates issues (normal in infants).
• Posturing:
  • Decorticate (cerebrum dysfunction) vs. Decerebrate (brain stem dysfunction).

Painful Stimuli in Assessment

• When Necessary: Explain to family.
• Types:
  • Central stimuli: Trapezius squeeze, suprasternal pressure.
  • Peripheral stimuli: Pen pressure on nail.

Final Notes for Nurses

• Report any neurologic changes.
• Pupil changes are late signs, level of consciousness is an early sign.
• Vital signs may change with neurological issues (e.g., increased ICP leads to high systolic BP and low pulse).