Brain Development and Adult Brain Structures Quiz

Brain Development

• The embryonic brain develops from a tube that slowly differentiates over time.
• The embryo is initially a hollow ball of cells that eventually forms into germ layers, which give rise to all body tissues, including the nervous system.
• The nervous system develops from a tube called the neural tube, which contains a fluid-filled internal cavity called the neurocoel.
• The neurocoel forms the chambers of the adult brain where cerebrospinal fluid will flow, becoming the ventricles of the brain and central canal of the spinal cord.

Primary and Secondary Vesicles

• The head portion of the neural tube enlarges to form three primary brain vesicles:
  • Prosencephalon (forebrain)
  • Mesencephalon (midbrain)
  • Rhombencephalon (hindbrain)
• These primary vesicles further divide into five secondary vesicles:
  • Telencephalon (cerebrum)
  • Diencephalon (epithalamus, thalamus, and hypothalamus)
  • Mesencephalon (midbrain)
  • Metencephalon (pons and cerebellum)
  • Myelencephalon (medulla oblongata)

Neural Protection

• The blood-brain barrier (BBB) is composed of endothelial cells, basement membrane, and astrocyte processes.
• The BBB prevents most molecules from passing through tight junctions between endothelial cells.
• Molecules cross the BBB through vesicular transport, active transport, facilitated diffusion, and simple diffusion.
• The blood-cerebrospinal fluid barrier (BCB) occurs in the choroid plexus in the ventricles of the brain.
• The BCB is composed of endothelial capillary cells, basement membrane, and ependymal cells.
• Molecules cross the BCB through similar transportation mechanisms as the BBB.