Neural tube development Flashcards
Neural tube & neural structures come from which layer?
ECTODERM
3 major brain regions in embryo & adult structures derived & functions…
FOREBRAIN -> telencephalon & diencephalon
- telencephalon -> olfactory lobes (smell), hippocampus (learning & memory), cerebrum
- diencephalon -> optic vesicles (vision), epithalamus, thalamus & hypothalamus (temp reg., sleep, breathing)
MIDBRAIN -> mesencephalon -> midbrain (motor control)
HINDBRAIN -> Metencephalon & myelencephalon
- Metencephalon -> Cerebellum (fine motor movements) & pons (mood control)
- myelencephalon -> medulla (reflex)
Neural tube closure…all 6 steps including diagrams (very important!!!)
- shaping - cells of the neural plate are identifiable in dorsal ectoderm
- folding - cells of medial hinge point (MHP) anchor to notochord & cells of presumptive epidermis pushed toward midline
- elevation - the 2 sides of the neural elevate, epidermal cells become opposed
- convergence - Cells of the dorsolateral hingepoint DLHP anchor to the overlying epidermis and become wedge-shaped
5 & 6. closure 5. The two sides of the neural tube contact with neural crest cells linking the neural tube to the epidermis 6. The NCC’s migrate away leaving the NT and epidermis separate
Failure of neural tube (NT) closure at different locations results in different NT defects. name & describe 2
Anterior neuropore - anencephaly -> brain fails to develop - lethal
Spina bifida - posterior neuropore
What is NCC? properties… (very important!!!)
Neural crest cells - A migratory cell population that detaches from the embryonic neural epithelium in streams to different regions of the embryo, where they contribute to the formation of various structures such as:
- Cardiac NCCs -> SEPTUM, separating pulmonary circulation from aorta
- Vagal & Sacral NCCs -> GANGLIA OF THE ENTERIC NERVOUS SYSTEM
- Trunk NCCs -> MELANOCYTES
- early NCC are pluripotent (can develop into any of the 3 germ layers)
