Lecture 4- Embryology Flashcards
What are the 3 layers of the trilaminar disc formed during the 3rd week of development?
Ectoderm
Mesoderm
Endoderm
What induces the ectoderm to form the neural plate?
Factors from the paraxial mesoderm and notochord induce the ectoderm to form the neural plate/neural ectoderm
What is neuralation? When does it occur?
Neuralation is the process by which the neural plate forms a neural tube. It occurs during the 3rd week of development and concludes w/the closing of the neuropores
When do the neuropores close?
4th week of development
What are the cells that inhabit the peak of the neural fold refer to as?
neural crest cells inhabit the peak of the neural fold
What does the lumen of the neural tube give rise to?
the ventricular system of the brain and the central canal of the spinal cord
What does incomplete closure of the dorsal neuropore result in?
spina bifida
What is spina bifida oculta?
Caused by incomplete closure of the caudal neuropore during development results in vertebral arches that fail to fuse int he lumbosacral region. Usually asymmptomatic except for a tuft of hair over the affected area.
What is spina bifida cystica?
Caused by an incomplete closure of the caudal neuropore resulting in vertebral arches that fail to fuse and neural tissue and meninges may protrude through the defect.
What results from an error in the closing of the rostral neuropore?
anencephaly
What develops from the alar plate?
Dorsal horn/Sensory
What develops from the basal plate?
Ventral horn/Motor
What does the ventricular zone give rise to in adults?
ependymal layer lining the ventricles and central canal
What does the marginal zone become in the spinal cord?
white matter
What does the mantle zone become in the spinal cord?
gray matter
What is the fictional division between the dorsal and ventral portions of the spinal cord?
Sulcus limitans
What develops from the sclerotome of the somite?
skeleton and cartilage
What develops from the myotome of the somite?
muscle
What develops from the dermatome of the somite?
dermis of the skin
What does the dorsal root ganglion develop from?
neural crest cells
What are the 3 parts in the initial 3 vesicle stage?
prosencephalon (forebrain)
mesencephalon (midbrain)
rhombencephalon (hindbrain)
What two structures develop from the prosencephalon?
Telencephalon
Diencephalon
What two structures develop from the rhombencephalon?
metencephalon
myelencephalon
What two flexures develop during the 3 vesicle stage?
mesencephalic flexure
cervical flexure
What flexure develops during the 5 vesicle stage?
pontine flexure
Which flexure persists into adulthood?
cephalic (cervical?)
What do neural crest cells develop?
sensory and parasympathetic ganglia cartilage and bone CT Endocrine cells melanocytes Dorsal root ganglia PNS supportive cells
What causes the walls of the neural tube to splay laterally in the brain stem region?
pontine flexure
