Neurulation and Neural Crest Flashcards
What is released by the Notochord to stimulate Neurulation? What receives this signal?
What is in the Neural Plate?
Neuroectoderm gives rise to what?
What is the process for forming Neural Tube and Neural Crest cells?
Shh - Received by the Ectoderm
Neural Folds and Neural Crest
Neural Tube
Neural Plate invaginates –> Neural folds approach each other forming Neural Groove –> Folds fuse forming Neural Tube and Neural Crest cells
What are the two types of ectoderm?
What else is formed during Neurulation?
Surface ectoderm
Neuroectoderm (CNS)
Neural Crest Cells
What days are the Rostral Neuropore and Caudal Neuropore (Neural Tube) closed?
What is Primary Neurulation and Secondary Neurulation?
Day 25 Rostral
Day 28 Caudal
Primary: Neural Tube Close from Brain –> Lumbar region of SC
Secondary: Neural Tube Closure for Sacral/Coccyx region, fusion of Caudal Emminence with Caudal Neuropore
What are Derivatives of Neural Crest Cells?
Sensory Neurons in PNS
Cranial Ganglia (CN V, VII, IX, X), Autonomic Ganglia, & Spinal Ganglia
Schwann Cells (Myelinate PNS)
Leptomeninges (Pia and Arachnoid Mater)
Pigment Cells (Melanocytes)
Bone and Cartilage of Face
Aorticopulmonary Septation
Enamel and Dentin
What are the four types of Congenital Neural Tube Defects? What causes these to occur?
What dietary substance is recommended to prevent these?
- Spinal Bifida Occulta, Meningocele, Menigomyelocele, Myelocele (Myeloschisis)
- Failure of Caudal Neuropore to close at appropriate time
- Folate
What is Spinal Bifida Occulta?
What is Meningocele?
What is Meningomyelocele?
What is Myelocele (Myeloschisis)?
What is the significance of a-Fetoprotein?
- Unfused Vertebral Arch; Asymptomatic
- Dura Mater creates cyst-like protrusion filled with CSF (no Vertebral Arch) - May or May Not have Defecits
- Dura mater creates cyst-like protrusion filled with CSF and spinal cord is migrated out into cyst (no vertebral arch) - Motor/Sensory Defecits
- Neural tube did not close and open exposure of Spinal Cord - Motor/Sensory Defecits - Requires surgery
- Increased a-F-P levels into Amniotic Fluid when there are Open Neural Tube Defects
What are the Congenital Cranial Neural Tube Defects and what causes them?
- Anencephaly (Missing Neocortex) & Encephalocele (with or without brain tissue)
- Failure of Rostral Neuropore to close at appropriate time
What is the Meninx Primitiva derived from and what does it form?
What does the Pachymenix give rise to and what part is it made from?
What does the Leptomeninges give rise to and what part is is made from?
Derived from Sclerotome (Mesoderm); Combines with Neural Crest Cells form all 3 Meninges
Dura Mater (Sclerotome)
Arachnoid and Pia Mater; (Neural Crest Cells)
When does Folding of the Embryo occur?
4th Week
