Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
47 Cards in this Set
- Front
- Back
What induces the ectoderm to differentiate into the neuroectoderm? What else does this form?
|
- Notochord induces ectoderm → neuroectoderm
- And forms the neural plate |
|
What does the neural plate give rise to?
|
- Neural tube
- Neural crest cells |
|
What does the notochord become?
|
Nucleus pulposus of the intervertebral disc in adults
|
|
What is the dorsal part of the neural plate? What is its function?
|
Alar plate - sensory
|
|
What is the ventral part of the neural plate? What is its function?
|
Basal plate - motor
|
|
What are the three primary vesicles that go onto become parts of the brain?
|
- Forebrain: Prosencephalon
- Midbrain: Mesencephalon - Hindbrain: Rhombencephalon |
|
What does the Prosencephalon become?
|
- Telencephalon → Cerebral hemispheres & Lateral Ventricles
- Diencephalon → Thalamus & Third Ventricle |
|
What does the Mesencephalon become?
|
Midbrain and Aqueduct
|
|
What does the Rhombencephalon become?
|
- Metencephalon → Pons, Cerebellum, and Upper part of Fourth Ventricle
- Myelencephalon → Medulla and Lower part of Fourth Ventricle |
|
What is the origin of the Telencephalon? What are the adult derivatives?
|
- Originates from forebrain / prosencephalon
- Walls become cerebral hemispheres - Cavity becomes lateral ventricles |
|
What is the origin of the Diencephalon? What are the adult derivatives?
|
- Originates from forebrain / prosencephalon
- Walls become thalamus - Cavity becomes the 3rd ventricle |
|
What is the origin of the Mesencephalon? What are the adult derivatives?
|
- Originates from midbrain / mesencephalon
- Walls become the midbrain - Cavity becomes the aqueduct |
|
What is the origin of the Metencephalon? What are the adult derivatives?
|
- Originates from the hindbrain / rhombencephalon
- Walls become the pons and cerebellum - Cavity becomes the upper part of the 4th ventricle |
|
What is the origin of the Myelencephalon? What are the adult derivatives?
|
- Originates from the hindbrain / rhombencephalon
- Walls becomes the medulla - Cavity becomes the lower part of the 4th ventricle |
|
What final neural structures originate from the neuroectoderm?
|
- CNS neurons
- Ependymal cells (inner lining of ventricles, makes CSF) - Oligodendroglia - Astrocytes |
|
What final neural structures originate from the neural crest?
|
- PNS neurons
- Schwann cells |
|
What final neural structures originate from the mesoderm?
|
Microglia (like macrophages, originates from the mesoderm)
|
|
What causes neural tube defects?
|
- Neuropores fail to fuse (4th week)
- Leads to persistent connection between amniotic cavity and spinal canal - Associated with low folic acid intake before conception and during pregnancy |
|
What are the signs of a neural tube defect?
|
- Elevated α-Fetoprotein (AFP) in amniotic fluid and maternal serum
- ↑ Acetylcholinesterase (AChE) in amniotic fluid is a helpful confirmatory test |
|
How does Acetylcholinesterase relate to neural tube defects?
|
- Fetal AChE in CSF transudates across the defect into the amniotic fluid
- ↑ AChE in amniotic fluid is a confirmatory test of a neural tube defect |
|
What are the types of neural tube defects?
|
Mild:
- Spina Bifida Occulta - Meningocele - Meningomyelocele Severe: |
|
What is the term for the failure of the bony spinal canal to close, but with no structural herniation?
|
Spina Bifida Occulta
|
|
What is wrong in Spina Bifida Occulta?
|
- Failure of bony spinal canal to close, with no structural herniation
- Usually seen at lower vertebral level - Dura is intact |
|
What type of neural tube defect is associated with a tuft of hair or skin dimple?
|
Spina Bifida Occulta - located at level of bony defect
|
|
What is wrong in Meningocele?
|
Meninges (but not spinal cord) herniate through the spinal canal defect
- Normal AFP (α-Fetoprotein) |
|
What is wrong in Meningomyelocele?
|
Meninges and spinal cord herniate through the spinal canal defect
|
|
What are the types of forebrain congenital anomalies?
|
- Anencephaly
- Holoprosencephaly |
|
What can cause an open calvarium with a frog-like appearance and no forebrain? Cause?
|
Anencephaly - malformation of anterior neural tube
|
|
What are the clinical findings of Anencephaly?
|
- ↑ AFP
- Polyhydramnios (no swallowing center in brain) - No forebrain and open calvarium |
|
What is Anencephaly associated with? What can help prevent it?
|
- Associated with maternal diabetes (type I)
- Maternal folate supplementation ↓ risk |
|
What goes wrong in Holoprosencephaly?
|
Failure of L & R hemispheres to separate
- Moderate from has a cleft lip / palate - Severe form results in cyclopia |
|
What causes Holoprosencephaly (failure of L&R hemispheres to separate)?
|
May be related to mutations in sonic hedgehog signaling pathway
|
|
What are the types of posterior fossa malformations?
|
- Chiari II Malformation (Arnold Chiari Malformation)
- Dandy-Walker |
|
What can cause herniation of the cerebellar tonsils and vermis through the foramen magnum with aqueductal stenosis and hydrocephalus, often with lumbosacral myelomeningocele and paralysis below the defect?
|
Chiari II Malformation (Arnold-Chiari Malformation)
- Type of posterior fossa malformation |
|
What are the problems in Chiari II (Arnold-Chiari Malformation)?
|
- Significant herniation of cerebellar tonsils and vermis through foramen magnum
- Aqueductal stenosis → hydrocephalus - Lumbosacral myelomeningocele → paralysis below defect |
|
What can cause agenesis of the cerebellar vermis with cystic enlargement of the 4th ventricle?
|
Dandy-Walker
- Type of posterior fossa malformation |
|
What are the problems in Dandy-Walker? What is it associated with?
|
- Agenesis of cerebellar vermis
- Cystic enlargement of 4th ventricle (fills enlarged posterior fossa) - Associated with hydrocephalus and spina bifidia |
|
What is the cause of Syringomyelia?
|
- A cyst or cavity forms within the spinal cord
- This cyst, called a syrinx, can expand and elongate over time, destroying the spinal cord |
|
What gets damaged by the cystic cavity within the spinal cord in patients with Syringomyelia?
|
Crossing anterior spinal commissural fibers are typically damaged first → "cape-like" bilateral loss of pain and temperature sensation in upper extremities (fine touch is preserved)
|
|
Where is Syringomyelia most often occurring?
|
C8-T1 (leading to "cape-like" distribution of defects)
|
|
What is Syringomyelia associated with?
|
Chiari I malformation (>3-5 mm cerebellar tonsilar ectopia; congenital, usually asymptomatic in childhood, manifests with headaches and cerebellar symptoms)
|
|
What forms the anterior 2/3 of the tongue? Functions?
|
- 1st and 2nd branchial arches
- Responsible for sensation via CN V3 and taste via CN VII |
|
What forms the posterior 1/3 of the tongue? Functions?
|
- 3rd and 4th branchial arches
- Sensation and taste mainly via CN IX - Extreme posterior of tongue via CN X |
|
What provides motor function to the tongue?
|
CN XII
|
|
What are the muscles of the tongue derived from?
|
Occipital myotomes
|
|
What nerves are responsible for sensation/pain in the tongue?
|
- Anterior 2/3: CN V3
- Posterior 1/3: CN IX and extreme posterior CN X |
|
What nerves are responsible for taste in the tongue?
|
- Anterior 2/3: CN VII
- Posterior 1/3: CN IX and extreme posterior CN X (solitary nucleus) |