Studydroid is shutting down on January 1st, 2019

by mtoom

Bookmark and Share

Front Back
What is neurulation?
Formation and closure of neural tube
When does neurulation occur?
Neurulation occurs in 3rd week of intrauterine life
What induces the surface ectoderm?
  • What are the next couple of steps? (5)
  • Induces surface ectoderm
  • Midline cells proliferate
  • Form thickened epithelium which folds
  • Neural tube closes
  • Surface ectoderm separates
Where does closure begin?
  • What directions does it proceed?
Closure begins in the cervical region
  • Proceeds in both upwards (cranial) and downwards (caudal) directions, in a zip-like fashion 
What are the last regions to fuse in neurulation?
  • Anterior (rostral), 25th day
  • Posterior (caudal), 27th day
The neural canal forms what 2 structures?
  • Central canal of spinal cord
  • Ventricles of the brain
Where are neural crest cells formed?
  • What is the origin of neural crest cells? 
Formed at the crests of the neural fold
  • Ectoderm 
What do neural crest cells detach from?
Detach from the surface ectoderm
Neural crest cells are damaged when mom does what?
  • Results in what syndrome? 
Drinks Alcohol
  • Fetal alcohol syndrome 
Fetal alcohol spectrum disorder (FASD) has what symptoms/effects? (5)
  • Mental retardation
  • Low birth weight
  • Delayed psychomotor skills
  • Facial abnormalities
  • Delayed psychological manifestations 
What are the 3 types of neural tube defects (spina bifida) in order of increasing severity?
  • Occulta
  • Cystica
  • Myeloschisis
Regarding neural tube defects, explain each a bit further:
  • Spina bifida occulta
  • Meningocele
  • Meningomyelocele
  • Myeloschisis 
  • Spina bifida occulta
    -Cord/dura are normal but spine incompletely closed 
  • Meningocele
    -Pouch of CSF-filled dura protrudes out of back 
  • Meningomyelocele
    -Pouch of CSF filled dura containing spinal cord protrudes out of back 
  • Myeloschisis
    -Spinal cord split open and exposed 
What happens when the anterior neuropore fails to close? *
Anencephaly (meroencephaly)
What are the neurological issues associated with neural tube defects? (4)
  • Skeletal muscle paralysis
  • Loss of anal and urethral (bladder) sphincter activity
  • Saddle anesthesia
  • Spina bifida cystica associated with Arnold-Chiari malformation 
What is the etiology of spina bifida?
How is spina bifida diagnosed? (2)
  • Ultrasound (8 weeks)
  • Alpha-fetoprotein (maternal serum, amniotic fluid) 
How do you prevent spina bifida? (1)
  • 0.4mg folic acid daily before and during pregnancy
At what level is the spinal cord in each stage of development? (3)
  • 3rd month
  • Birth
  • Adult 
  • 3rd month → Coccyx
  • Birth → L3
  • Adult →  L1/L2
Difference between cauda equina and filum terminale?
  • Cauda equina: Spinal nerves
  • Filum terminale: Fibrous tissue that anchors spinal cord
Why are the lower spinal nerves really angulated in adults?
Because spinal cord does not grow as fast as vertebrae
  • Spinal cord gets left behind 
With the closure of the anterior neuropore, the cranial end of the neural tube shows what?
3 Dilatations
What do the 3 dilatations in the anterior neuropore form?
The 3 dilatations form the primary brain vesicles
What are the 3 primary brain vesicles? (provide both names)
  • Forebrain (Prosencephalon)
  • Midbrain (Mesencephalon)
  • Hindbrain (Rhombencephalon)
What 2 structures form from the forebrain (prosencephalon)?
  • Telencephalon
  • Diencephalon
What 2 structures form from the hindbrain (rhombencephalon)?
  • Metencephalon
  • Myelencephalon
What structures form from the telencephalon? (1)
Cerebral hemispheres
What structures form from the diencephalon? (2)
What structures form from the mesencephalon? (3)
  • Midbrain
  • Cerebral peduncles
  • Superior/inferior colliculi
What structures form from the metencephalon? (2)
  • Pons
  • Cerebellum
What structures form from the myelencephalon? (1)
Medulla oblongata
What are the 3 flexures of the brain?
  • Cervical flexure
  • Midbrain flexure
  • Pontine flexure
Describe what is demarcated by each flexure?
  • Cervical flexure
  • Midbrain flexure
  • Pontine flexure
  • Cervical flexure
    -Demarcates brain and spinal cord 
  • Midbrain flexure
    -Demarcates forebrain (cerebral hemispheres) from midbrain 
  • Pontine flexure
    -Demarcates hindbrain from midbrain 
What are the consequences of the brain flexures? (2)
  • Alteration in basic arrangement of cell groups and nerve fibers
  • Flexure in pontine region causes a thinning of dorsal wall (roof) of brain
What happens to brain structure as you move from the spinal cord to the myelencephalon?
  • At what structure does this occur? 
The roof plate opens up
  • Occurs at pontine flexure 
x of y cards