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25 Cards in this Set
- Front
- Back
What is neurulation?
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Neurulation refers to the formation and closure of the neural tube
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Describe the role of the notocord in the development of the neural tube
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1. The notocord induces the overlying ectoderm to differentiate into neuroectoderm and form the neural plate
2. The notocord forms the nucleus pulposus of the intervertebral disk in the adult |
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What does the notocord form in the adult?
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The nucleus pulposus of the intervertebral disk
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Describe the formation of the neural plate
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The notocord induces the overlying ectoderm to differentiate into neuroectoderm and form the neural plate
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Describe the formation of the neural tube
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The neural plate folds to give rise to the neural tube, which is open at both ends at the anterior and posterior neuropores. The anterior and posterior neuropores connect the lumen of the neural tube with the amniotic cavity
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What connects the lumen of the neural tube with the amniotic cavity?
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The anterior and posterior neuropores
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Describe the posterior neuropore
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1. Closes during week 4 (day 27)
2. Failure of the posterior neuropore to close results in lower neural tube defects (eg, spina bifida with myeloschisis) |
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Describe the anterior neuropore
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1. The anterior neuropore closes during week 4 (day 25)
2. It becomes the lamina terminalis 3. Failure of the anterior neuropore to close results in upper neural tube defects (NTDs; e.g., anencephaly) |
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Describe the formation of the lamina terminalis
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The anterior neuropore closes
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Describe the formation of neural crest cells
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The neural crest cells differentiate from neuroectoderm of the neural tube and form a column of cells along both sides of the neural tube
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What does the rostral part of the neural tube form?
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The adult brain
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What does the caudal part of the neural tube form?
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The adult spinal cord
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What forms the adult brain?
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The rostal part of the neural tube
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What forms the adult spinal cord?
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The caudal part of the neural tube
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Describe the development of the lumen of the neural tube
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The lumen of the neural tube gives rise to the ventricular system of the brain and central canal of the spinal cord
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What gives rise to the ventricular system of the brain?
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The lumen of the neural tube
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Describe the migration of neural crest cells
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Neural crest cells undergo a prolific migration throughout the embryo (both the cranial region and the trunk region) and ultimately differentiate into a wide array of adult cells
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What do the cranial region neural crest cells differentiate into?
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1. Pharyngeal arch skeletal and connective tissue components
2. Bones of neurocranium 3. Pia and arachnoid 4. Parafollicular (C) cells of thyroid 5. Aorticopulmonary septum 6. Odontoblasts (dentin of teeth) 7. Sensory ganglia of CN V, CN VII, CN IX, CN X 8. Ciliary (CN III), pterygopalatine (CN VII), submandibular (CN VII), and otic (CN IX) parasympathetic ganglia |
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What do the trunk region neural crest cells differentiate into?
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1. Melanocytes
2. Schwann cells 3. Chromaffin cells of adrenal medulla 4. Dorsal root ganglia 5. Sympathetic chain ganglia 6. Prevertebral sympathetic ganglia 7. Enteric parasympathetic ganglia of the gut (Meissner and Auerbach; CN X) 8. Abdominal/pelvic cavity parasympathetic ganglia |
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Describe neurocristopathy
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Neurocristopathy is a termed used to describe any disease related to maldevelopment of neural crest cells
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Describe medullary carcinoma of thyroid
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1. Medullary carcinoid of the thyroid is an endocrine neoplasm of the parafollicular (C) cells of neural crest origin that secrete calcitonin
2. The carcinoma cells are usually arranged in cell nests surrounded by bands of stroma containing amyloid |
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Describe Schwannomas
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1. A schwannoma is a benign tumor of Schwann cells of neural crest origin
2. These tumors are well circumscribed, encapsulated masses that may or not be attached to the nerve 3. The most common location within the cranial vault is at the cerebellopontine angle near the vestibular branch of CN VIII (often referred to as an acoustic neuroma) 4. Clinical findings include tinnitus and hearing loss 5. CN V (trigeminal nerve) is also commonly affected |
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Describe the tumors of Schwannomas
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These tumors are well circumscribed, encapsulated masses that may or not be attached to the nerve
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Describe the most common location of Schwannomas
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The most common location within the cranial vault is at the cerebellopontine angle near the vestibular branch of CN VIII (often referred to as an acoustic neuroma)
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What are the clinical findings associated with Schwannomas?
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Clinical findings include tinnitus and hearing loss
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