[HAP-02] Nervous System Anatomy & Physiology: CNS, Blood–Brain Barrier, Synaptic Transmission & Pain Pathways

HAP-02 • 1. Anatomy & Physiology

Learning Objectives

Describe the anatomical divisions of the brain, spinal cord tracts, meninges, CSF circulation, and Blood–Brain Barrier (BBB) tight junctions.; Contrast the 4 major central dopaminergic pathways (Mesolimbic, Mesocortical, Nigrostriatal, Tuberoinfundibular) and their clinical pharmacology.; Trace ascending nociceptive (Aδ and C fibres, Substance P, glutamate) and descending analgesic pathways.

Chapter Overview & Core Explanation

The central nervous system processes every sensation, movement, and thought through specialized neural circuits protected by the Blood–Brain Barrier—except at the Chemoreceptor Trigger Zone (CTZ), which samples the blood directly to trigger vomiting when toxins are detected.

Key Exam & Clinical Takeaways

• The Chemoreceptor Trigger Zone (CTZ / Area Postrema) lies functionally outside the Blood–Brain Barrier, allowing peripheral antiemetics ([5.14] Domperidone) to act without central extrapyramidal toxicity.
• Bacterial meningitis inflammation disrupts BBB tight junctions, dramatically increasing CSF penetration of β-lactams ([8.15] Ceftriaxone, [8.22] Meropenem) and [8.48] Vancomycin.

Open Interactive Platform & Full Workspace →