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Presentation on Development of Brain.pptx
- 1. DEVELOPMENT OF BRAIN DRA BHARATH NEUROSURGERY RESIDENT
- 2. END OF 2ND WEEK (i)Circular disc Pear shaped & (ii) Prochordal Plate appears Cephalocaudal & Rt / Lt axes are established
- 3. 3RD WEEK (15TH DAY) PLEURIPOTENT CELLS PRIMITIVESTREAK Actively migrate & Invaginate b/w 2 layers of embryonal disc
- 4. DURING 3RD WEEK PRIMITIVE KNOT PRIMITIVENODE HENSENS NODE PRIMITIVE STREAK CRANIAL END THICKENS
- 5. DURING 3RD WEEK PRIMITIVE KNOTCAVITY / PIT FORMS IN THE CENTRE PRIMITIVE PIT BLASTOPORE
- 6. DURING 3RD WEEK PRIMITIVE KNOT CELLSMULTIPLY, MIGRATE CEPHALAD, UPTO PROCORDAL PLATE NOTOCHORDAL PROCESS
- 7. DURING 3RD WEEK BLASTOPORE EXTENDS INTOTHE GROWING NOTOCHORDAL PROCESS NOTOCHORDAL CANAL
- 8. END OF 3RD WEEK Cellsof floor of Notochord INTERCALATED with Endoderm NOTOCHORDAL PLATE BREAKDOWN DEFINITIVE NOTOCHORD INVOLUTES OVER ITSELF CELLS PROLIFERATE & FILL THE CAVITY
- 10. PRIMITIVE STREAK PRIMARY ORGANIZER INDUCES INDUCES NEURECTODERM & NEURALTUBE FORMATION NOTOCHORD ULTIMATE FATE Regresses by end of 3rd week Disappears by 26th day Remains as 1. NUCLEUS PULPOSUS 2. APICAL LIGAMENT OF DENS
- 11. NOTOCHORD REMANANTS • Chordomas– Malignant tumors in midline • Thorn waldt cyst – involution of cranial end • Ecchordosis physaliphora - Hamartoma
- 12. BEGINNING OF NEUROEPITHELIUM •PRIMARY NEURULATION • SECONDARY NEURULATION • REGRESSION OF PRIMITIVE STREAK
- 13. PRIMARY NEURULATION Neural Plate 16th day Neural tube 22-25th day Neuralgroove and folds 20 / 21st day
- 14. SECONDARY NEURULATION Anterior Neuropore Closesby 25th day Represented by Lamina Terminalis Middle of the Neural Tube Earliest to close 21 / 22nd day Posterior Neuropore 28th day Represented by Terminal Ventricle
- 15. REGRESSION OF PRIMITIVESTREAK Regresses by end of 3rd week Disappears by 26th day
- 18. OVERVIEW OF CNS ORIGINS Bloodvessels of the Skull and Brain
- 19. NEURAL CREST CELLDERIVATIVES NEURAL CREST CELLS DORSAL MASS VENTRAL MASS NEUROBLASTS 1. DORSAL ROOT GANGLIA OF SPINAL NERVES 2. SENSORY GANGLIA OF 5, 7, 8, 9, 10 CRANIAL NERVES 1. SYMPATHOBLASTS – SYMP / PARASYMP GANGLIA 2. CHROMAFFIN CELLS – ADRENAL MEDULLA, AORTIC BODY, EC CELLS SPONGIOBLASTS 1. SATELLITE CELLS 2. SCHWANN CELLS PLEURIPOTENT CELLS 1. ODONTOBLSTS, DENTINE 2. MELANOBLASTS 3. LEPTOMENINGES 4. BRANCHIAL ARCH CARTILAGES OTHERS
- 20. NEURAL CREST CELLDERIVATIVES OTHERS 1. FACIAL BONES, PART OF SKULL BONES 2. CILIARY BODY 3. SMOOTH MUSCLE IN DERMIS 4. C CELLS OF THYROID 5. SEMILUNAR VALVES, CONO TRUNCAL SEPTUM 6. SMOOTH MUSCLES IN BLOOD VESSELS OF FACE AND FOREBRAIN
- 21. CELL DIVISION WITH INTHE NEURAL TUBE Single Columnar cell layer Cell division and migration of cells Pseudo stratified 3 layered model INTERKINETIC MIGRATION • Neuroblast – unable to divide
- 22. THREE LAYERED MODEL OFTHE NEURAL TUBE
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- 25. FORMATION OF NEUROGLIALCELLS Germinal cells after it ceases to produce neuroblasts Mantle zone Marginal zone Medulloblasts / spongioblasts Astroblasts oligodendroblasts Astrocytes oligodendrocytes Protoplasmic Fibrous Glioblasts
- 26. MYELINATED, UNMYELINATED NEURONS • Mesaxonformation • Winding / spiralling of mesaxon • Inside CNS – Oligodendrocytes • In PNS – Schwann cells
- 27. FATE OF 3LAYERS OF NEURAL TUBE Germinal Layer After neuroblasts and glioblasts differentiation Mantle Layer Contains Cell bodies of Neuroblasts and Astroblasts Marginal Layer Contains Axons and Oligodendrocytes Ependymal Layer Grey Matter White matter
- 28. CRANIAL END OFNEURAL TUBE END OF 4TH WEEK START OF 5TH WEEK
- 29. DERIVATIVES OF BRAINVESICLES
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- 46. CEREBRAL CORTEX PALEO CORTEXARCHI CORTEX NEO CORTEX 1. HIPPOCAMPUS 2. DENTATE GYRUS 3. INDUSIUM GRISIUM 1. PYRIFORM CORTEX 2. UNCUS 3. PARAHIPPOCAMP AL GYRUS 4. ANT PERFORATED SUBSTANCE FRONTAL, PARIETAL, OCCIPITAL, TEMPORAL LOBES, INSULA OLFACTORY
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- 49. NEO CORTEX EACH VESICLEGROWS 1. FORWARDS – FRONTAL LOBE 2. UPWARD – PARIETAL LOBE 3. BACKWARDS – OCCIPITAL LOBE 4. ANT INFERIORLY – TEMPORAL LOBE
- 50. MIGRATION OF NEUROBLASTSIN NEOCORTEX MANTLE LAYER OF TELENCEPHALON MARGINAL LAYER OF TELENCEPHALON FOURTH WAVE THIRD WAVE SECOND WAVE FIRST WAVE NEUROBLASTS THAT DONOT MIGRATE CORPUS STRIATUM
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- 52. MENINGES • DURA –MESENCHYME • ARACHNOID, PIA - NEUROEPITHELIUM