Blood brain barrier
BBB Locations:
→ Formed by TIGHT JUNCTIONS & FOOT PROCESSES OF ASTROCYTES.
→ ABSENT BBB = CIRCUMVENTRICULAR ORGANS (mnemonic – SOAP)
→ S= Subfornical organ; O – Organum Vasculosum of Lamina Terminalis; A – Area Postrema; P – Posterior Pituitary
BBB Permeability:
PERMEABLE Substance:
• Glucose (GLUT-1),
• Water (Aquaporin-4),
• Gases (CO2, O2, N2),
• Lipid soluble hormones (Steroids)
NON-PERMEABLE Substance:
• Protein Hormones,
• Dopamine (L-dopa in Parkinsonism),
• H+ ions