T3: Neurodevelopment Flashcards
A newborn patient presents with a sac protuded from the posterior portion of his head containing meninges, CSF, brain tissue with ventricles, and glial tissues. The embryologic origin is resulted from the failure of ___ and resulted in ____? (mm)
A) Posterior Neuropore closure, Myeloschsis
B) Anterior Neuropore closure, Encephalocele
C) R and L Hemisphere separation, Encephalocele
D) Lateral Neuromesoderm closure, Meningocele
Answer:B
A) aka spina bifida
C) R and L hemisphere separation failure is Holoprosencephaly and SHH, Cleft lip/palate, cyclopia, and Fetal alcohol syndrome.
D) made it up
Your patient presents with Deep crevices because parts of the cortex are absent and it is replaces by CSF. This is due to which genes ___ and ___; the defect is called ____?(mm)
A) HOX, TAU, Old Age Degeneration B) HOX, Pax6, Aniridia C) Rh4, Rh6, Rhombomere D) PMP-22, Netrin1, Charcot Marie E) Emx, Otx, Schizencephaly
Answer: E- Emx and Otx genetic defect cause Schizencephaly which is a rare human congental malformation of the prosencephalon and mesencephalon. It is characterized by deep crevices because part of the cortex is replaces by CSF.
B) Just Pax6 fuck up can cause aniridia and foveal hypoplasia. Pax6 is the master control gene and inducts all regions of developing eye and other brain structures.
D) Just PMP-22 is asscociated with Charcot Marie tooth disease. Netrin 1 is the long range chemoattractant for the floor plate
A 17 year old girl comes to your office complaining of limb weakness and clumsiness. You examine her limbs and notice her biceps are very jiggly. Her mother says that the Childs grandmother has something similar but because she was so old and medicine sucked back in the day they never bothered to figure it out and she just smoked pot for the pain and used a cane since late childhood. What AA substitution is present in this child? (mm)
A) Gly by Asp B) Glu by Phe C) Ala by Tyr D) His by Asp E) Ala by Asp
Answer: A - This patient is presenting with the classic signs of Charcot Marie tooth disease. Limb Weakness due to muscle atrophy, sensory neuropathy, late childhood, and non fatal (her grandmas has it). The AA change is Gly by Asp in the PMP-22 gene.
Efficiency of muscle innervation is increased during the 25th week of gestation. How is this achieved? (MG)
A. Retrograde degeneration and muscle atrophy
B. Condensation and neurotransmitter clearance
C. Necrosis and muscle fiber fusion
D. Apoptosis and synapse elimination
D. Apoptosis and synapse elimination
This question is purposefully vague, as our exams sometimes are.
By the 25th week of gestation, muscle innervation switches from the less efficient polyneural innervation to the more efficient mononeural innervation. This means you have to get rid of the extra neurons. This is achieved through apoptosis of the neuron and elimination of that neuron’s synapse.
A poor orange baby kitty cat was hit by a car right outside of container park. He was probably hit by a car due to underdeveloped eyesight in his right eye. In which layers of the brain would you find the nerve fibers that innervate the right side of each eye in a full mature kitty cat with good vision? (MG)
A. Layers IV and V of the cortex and same layer of lateral geniculate nucleus thalamus
B. Layer IV of the cortex and different layers of the lateral geniculate nucleus thalamus
C. Layer V of the cortex and different layers of the nucleus thalamus
D. Layers IV and V of the cortex and different layers of the lateral geniculate nucleus thalamus
B. Layer IV of the cortex and different layers of the lateral geniculate nucleus thalamus
A cat with defective eyesight is described in the vignette, but the question stem is asking for a cat that has equal bilateral vision.
Layer IV of the cortex should contain nerve fibers from both eyes
The lateral geniculate nucleus of the thalamus is comprised of two layers: one layer contains only nerve fibers connected to the right side of the left eye, and the other layer contains only nerve fibers from the right side of the right eye.
See pink and green diagram in this lecture if there’s confusion.
A patient is found to have severe hypomyelination of schwann cells. What is the defective gene? (MG) A. SHH B. WT-1 C. PMP-22 D. HMSN
C. PMP-22 contains a mutation that results in Charcot-Marie-Tooth Disease, which is characterized by severe hypomyelination of Schwann cells
WT-1 is the defective gene in Wilm’s Tumor
SHH is the gene responsible for limb development/placement
HMSN is not a gene, but a characterization of Charcot-Marie-Tooth and stands for hereditary motor and sensory neuropathy
Child is born with one eye and a cleft lip. What was the malformation during development?
A. Failure of Neural Crest Cells to Migrate
B. Mutation of the PMP-22 Gene
C. Failure of Left and Right Hemispheres to seperate
D. Failure of the anterior Neuropore to close
RFA
C. Failure of Left and Right Hemispheres- Patents has Holoprosencephaly
A. Neural Crest cells do a lot of things but not this time
B. PMP-22 Gene Mutation- is Charcot Marie Tooth disease
D. Failure Neuropore Close- Encephalocele
In a lab some mice were injected with Nerve Growth Factor. What is the expected outcome?
A. The mice have over stimulated motor neurons and have tremors
B. The mice’s sympathetic nervous system was affected giving them poor stress response.
C. The mice sensory neurons were left unaffected
D. The mice parasympathetic nervous system was affected making them more fearful.
RFA
B. NGF was show on studies on mice to effect the Sympathetic nervous system and sensory nervous system resulting in poor stress response.
A. Motor neurons are unaffected by NGF
C. NGF acts on sensory and sympathetic neurons
D. NGF doesn’t act on parasympathetic system
A man is studying the development of embryos and notices in a specimen that HOX gene expression is inconsistent with what he expected. After further examination he finds that the specimen is lacking Hensen’s nodes. What is the function of Hensen nodes.
A. Direct activation by release of protylic enzymes
B. Production of retinoic acid, increasing HOX
C. Production and secretion of NGF to increase nerve development
D. Inhibits ROBO allowing HOX to work with Netrin 1
RFA
B. Production of retinoic acid, increasing HOX
All the other Hensen Nodes have no effect on
