Week 3: Neuralation Flashcards
What is a sacrococcygeal teratoma?
A sacrococcygeal teratoma is a tumor of randomly differentiated cells that come from reminants of the primitive groove that continued to divide randomly. You will find random teeth, hair, bone, and muscle there.
What is the notochord?
It is the result of the invagination that occurs from the epiblast from the primitive groove down into where the cell starts to create a notochordal canal caudally towards the prechordal plate (soon to be mouth).
***This structure will create the longitudinal axis for the embryo
What is the notochordal plate?
It occurs after the immature notochord is made. The Notochord cells will fuse with the ectoderm and then it will create a notochordal plate (looks like a tunnel connected to the ectodermal layer above it)
What does the notochordal plate become?
The notochordal plate will later become the neural plate. The neural plate will separate into 2 different structures: the neural tube and the neural crest cells that are laterally remaining cells from invagination.
What is a cordoma?
This is due to abnormal growth from the remnants of the notochord plate (differentiates into neural tissue) and will be found in the spheno-occipital region of the head.
What is released by the notochord to create the 2 neural layers?
Sonic hedgehog protein released by the notochord will create the neural plate and the neural tube.
What will the Neural Tube give rise to?
The neural tube will give rise to the CNS (brain and spinal cord)
When does the rostral and caudal neural pores close?
Rostral neural pore closes at day 25 (mid week 4) and the caudal end will close at day 28 (late week 4)
What are the neural crest cells?
The neural crest cells are cells that remain after the neural plate has formed the neural tube with neural crest cells pinching off laterally.
What do the neural crest cells become?
Sensory Neurons
Ex: Cranial Nerves (5, 7, 9, 10), schwann cells, satellite cells, leptomeninges, melanocytes, parts of the teeth
What does a problem with the neural crest cells cause?
Neurocristopathies–>
Hirschsprung’s Disease: Cleft palate, neuroblastoma, albinism
What happens if the pores from the neural plate don’t fold properly to form the neural tube at the caudal end?
This will form the Spinal Bifida Oculta which is a delay in the zippering of the neural tube at the caudal end.
Sx: Tuft of hair on their tail bone
What is a meningocele? (caudal end deficit)
This is a cyst that forms when the neural tube doesn’t close on time and the result is a pool of CSF build up in the Dura Mater which protrudes out like a cyst.
What is a meningomyocele? (caudal end deficit)
This is a HUGE problem where both the spinal cord and the meninges are out of the vertebral column that have FREELY EXPOSED SPINAL CORD
Sx: sensory and motor defects in lower extremities.
What is a myelocele? (caudal end deficit)
Openly exposed spinal cord for the child that causes motor and sensory deficits
