✅ EMBRIOLOGÍA del SISTEMA NERVIOSO CENTRAL (Parte 1°) 🧠⚡
Embryology of the Central Nervous System
Introduction to the Central Nervous System Development
- The central nervous system begins to develop in the third week as a thickened ectodermal plate known as the Neural Plate.
- This structure is located in the dorsal mid-region, anterior to the primitive ganglion.
Formation of the Neural Tube
- Lateral edges of the Neural Plate elevate to form Neural Folds, which eventually fuse to create the Neural Tube.
- Fusion starts at the cervical region and progresses both cranially and caudally, forming openings called neuropores that connect with amniotic cavity.
Closure of Neuropores
- The closure of the cranial neuropore occurs around day 25, during 18 to 20 somite stages, while closure of caudal neuropore happens three days later.
- The cranial end of the neural tube develops into three primary brain vesicles: Prosencephalon (forebrain), Mesencephalon (midbrain), and Rhombencephalon (hindbrain).
Differentiation into Secondary Brain Vesicles
- By week five, primary brain vesicles differentiate into five secondary vesicles:
- Prosencephalon → Telencephalon and Diencephalon
- Mesencephalon remains unchanged
- Rhombencephalon → Metencephalon and Myelencephalon.
Key Structures Derived from Brain Vesicles
- Major structures include:
- Telencephalon: Cerebral Hemispheres
- Diencephalon: Optic Vesicle, Thalamus, Hypothalamus, Pituitary Gland
- Mesencephalon: Superior and Inferior Colliculi
- Metencephalon: Cerebellum and Pons
- Myelencephalon: Medulla Oblongata.
Ventricular System Overview
- The central canal of the spinal cord continues with brain ventricles:
- Fourth Ventricle in Rhombencephalon,
- Third Ventricle in Diencephalon,
- Lateral Ventricles in Cerebral Hemispheres.