what is the function of the proteins secreted by cells of the ventral midline of the spinal cord
Neural tube The neural tube patterns along the dorsal-ventral axis to establish defined compartments of neural progenitor cells that lead to distinct classes of neurons.[2] According to the French flag model of morphogenesis, this patterning occurs early in development and results from the activity of several secreted signaling molecules. Sonic hedgehog (Shh) is a key player in patterning the ventral axis, while bone morphogenic proteins (BMPs) and Wnt family members play an important role in patterning the dorsal axis.[3] Other factors shown to provide positional information to the neural progenitor cells include fibroblast growth factors (FGFs) and retinoic acid. Retinoic acid is required ventrally along with Shh to induce Pax6 and Olig2 during differentiation of motor neurons.[4]
Meninges The meninges (/məˈnɪndʒiːz/,[1][2] singular: meninx (/ˈmiːnɪŋks/ or /ˈmɛnɪŋks/[3]), from Ancient Greek: μῆνιγξ, translit. mēninx, lit. 'membrane',[4] adjectival: meningeal /məˈnɪndʒəl/) are the three membranes that envelop the brain and spinal cord. In mammals, the meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system.