Where is the boundary between PNS & CNS?

• Where is the boundary between PNS & CNS?

• Pia of cord and brain. The determining structure is Basement Membrane.

• All excitable cells and supporting cells of PNS are encapsulated in basement membrane (BM).

• Basement membrane is a continuous component of Pia.
• BM is at the base of both ectoderm and entoderm,
• BM abuts astrocyte-endfeet forming the surface of the CNS.
• BM is the center of the pial boundary
• BM encapsulates all PNS neuronal structures as well as muscle and Schwann cells.