Neurodevelopment

Question 1

describe the importance of NGF during development

Answer 1

• antibodies to NGF inhibit development of sensory and sympathetic neurons
  
  • the animals showed poor response to stress
• parasympathetic and motor neurons were relatively unaffected

Question 2

describe the importance of BDNF during development

Answer 2

Part of the neurotrophin family

BDNF helps in making the CNS

Question 3

describe the cause of spina bifida (myeloschisis)

Answer 3

occurs when the posterior neuropore fails to close

Question 4

describe the cause of encephalocele

Answer 4

failure of portions of the anterior neuropore to close

manifested by the protrusion of a sac from the cranium consisting of portions of the meninges and CSF, glial tissue and brain substance with/without ventricles

Question 5

what are biomarkers that may indicate a neural tube defect?

Answer 5

• increased AFP
• increased AChE

Question 6

describe derivatives of the neural plate -> neural crest and neural tube

Answer 6

Question 7

describe the role of BMP in neural induction

Answer 7

• BMP inhibits the formation of neuroectoderm
  
  • in order to inhibit BMP to form neuroectoderm, chordin and noggin are made

Question 8

describe what determines Hox gene expression

Answer 8

Hox gene expression in the rhombencephalon is determined partly by a longitudinal gradient of retinoic acid

Retinoic acid is produced by Hensen’s node

Question 9

SHH influences the ____ patterning of the neural tube

BMP influences the ____ patterning of the neural tube

Answer 9

SHH influences the ventral patterning of the neural tube

BMP influences the dorsal patterning of the neural tube

Question 10

describe the role of netrin and slit in neurodevelopment

Answer 10

• netrin and slit define long range axonal migration in the developing spinal cord

Question 11

describe the role of peripheral myelin protein (PMP-22)

Answer 11

• secreted by Schwann cells
• essential for layering Schwann cell membrane as myelin
• mutation in PMP-22 = severe hypomyelination
• humans = Charcot Marie Tooth disease
  
  • peripheral neuropathy
  • ​single AA substitution (Gly by Asp)

Question 12

describe Charcot Marie Tooth Disease

Answer 12

• associated with dysfunctional PMP-22 gene
• most common inherited neurological disorder
• hereditary motor and sensory neuropathy
• symptoms and signs appear in late childhood or in adulthood and more commonly include that of chronic degeneration of peripheral nerves, such as muscle atrophy and sensory ataxia leading to clumsiness

Question 13

during the embryonic stages, muscle fibers are _____

apoptosis occurs, which makes muscles fibers ____ during the post-natal phase

Answer 13

during the embryonic stages, muscle fibers are polyneural

apoptosis occurs, which makes muscles fibers mononeural during the post-natal phase

Question 14

describe the importance of critical periods in vision

Answer 14

• early visual experience influences particular cortical connections
• ocular dominance columns become well defined in layer IV at 6 weeks of age
  
  • this patterning does not occur if an eye is lost in infancy; instead the remaining eye fails to retract its terminal fibers to the normal column borders