Author/Editor		Petrovič, Danijel
Title		Embriologija živčevja
Translated title		Embryology of the nervous system
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 39, št. 4
Publication year		2000
Volume		str. 381-8
Language		slo
Abstract		The notochord and para-axial mesoderm induce the overlying ectoderm to differentiate into the neural plate. Formation of the neural tube begins in the fourth week, when the walls of the neural tube thicken to farm the brain and spinal cord. The neural canal is converted into the ventricular system of the brain and the central canal of the spinal cord. In the fourth week of development, the cranial part of the neural tube shows three protrusions known as primary brain vesicles the prosencephalon, embryonic mesencephalon and rhombencephalon. The mesenchyma surrounding the neural tube condenses to form a membrane called the primordial membrane, from which the dura mater and the pia-arachnoidea are formed. The cerebrospinal fluid begins to appear in the fifth week. The axtons are non-myelinated at the beginning; nerve myelination begins at about 20 weeks. Initially, the surface of the hemispheres is smooth, but as growth proceeds, sulci and gyri develop.
Summary		Iz ektoderma se pod vplivom dorzalne horde in paraaksialnega mezoderma razvije nevralna plošča, ki je osnova za nastanek živčnega sistema. Nevralna cev se začne tvoriti v četrtem tednu razvbja ploda: Iz zadebeljene stene nevralne cevi nastanejo možgani in hrbtni mozeg, iz nevralnega kanala pa nastane centralni kanal in možganski ventrikli. Iz kranialnega dela nevralne cevi se v četrtem tednu razvijejo trije možganski vezikli: prozencefalon (zasnova za možganski hemisferi in diencefalon - talamus), embrionalni mezencefalon (zasnova za mezencefalon) in rhombencefalon (zasnova za pons in male možgane ter podaljšan hrbtni mozeg). Iz mezenhima, ki obdaja nevralno cev, nastane primordialna membrana, iz te pa čvrsta in mehka možganska ovojnica. Cerebrospinalna tekočina se začne tvoriti v petem tednu plodovega razvoja. Pri plodu so živa sprva nemielinizirani, mielinizacija živcev se začne v dvajsetem tednu razvoja ploda in poteka še pri novorojencu. Površina možganskih hemisfer, ki je sprva gladka, postaja vse bolj razbrazdana.
Descriptors		NERVOUS SYSTEM SPINAL CORD GANGLIA, SPINAL BRAIN MEDULLA OBLONGATA MESENCEPHALON DIENCEPHALON BASAL GANGLIA PITUITARY GLAND TELENCEPHALON