Week 1

Question 1

Otx2

Answer 1

Transcription factor needed for proper anterior neural tube differentiation;
Absence results in anancephaly (no head)

Question 2

Sperry Frog Eye Experiment Neurotrophic Factors

Answer 2

EphrinA - repellant, found in posterior tectum

EphrinB - attractant found in ventral tectum

Question 3

Robo-3 and associated clinical syndrome

Answer 3

Neuronal guidance cue. Genetic defect leads to horizontal gaze palsy in humans, non-decussating neurons in fish causing withdrawal reflex toward stimulus

Question 4

Synonym for anterolateral tract (and function)

Answer 4

Spinothalamic; Pain and temperature

Question 5

Most common motor neuron disease

Answer 5

ALS - Amyotrophic Lateral Sclerosis

Question 6

Disease similar to ALS though more common in kids?

Answer 6

SMA - spinal motor atrophy

Degeneration of motor neurons selectively

Question 7

PMP22 gene clinical relevance

Answer 7

Deletion –> HNPP
Duplication –> CMT1A (Charcot–Marie–Tooth disease)
Both are inherited demylinating neuropathies

Question 8

Lambert-Eaton Syndrome cause and symptoms

Answer 8

Autoantibodies against Ca channels in presynaptic terminals of neuromuscular junction;
Myopathy; common after squamous cell lung cancer

Question 9

Myasthenia Gravis cause and symptoms

Answer 9

Autoantibodies against ACh receptors of neuromuscular junction
Weakness that increases with uses

Question 10

Nerve gas (Sarin) mechanism of action
& another clinically used chemical with same mechanism

Answer 10

• Acetylcholine esterase inhibitor
• Chronic depolarization of muscle at NMJ
• Loss of contraction of diaphragm –> death
• Succinylcholine (used before intubations) does the same thing

Question 11

Spinal chord blood supply

Answer 11

1 anterior spinal artery: Anterior 2/3 of both spinal hemispheres
2 posterior spinal arteries: Posterior 1/3 of spinal hemisphere

Question 12

Fasciculations vs. fibrillations

Answer 12

Fasiculations are macroscopic muscle twitches diagnostic of LMN problems
Fibrillations are microscopic twitches picked up on EMG; diagnostic of denervation of muscle

Question 13

Location of Clarke’s Nucleus

Answer 13

Medial and ventral part of dorsal horn (just posterior to intermediate zone

Question 14

Function of Clarke’s Nucleus

Answer 14

• 2nd order neuron somas

- Unconscious proprioception (Ia, Ib fibers) from ipsilateral lower limb

Question 15

Nemaline myopathy involved genes

Answer 15

• Most commonly actin

- Tropomyosin or nebulin as well

Question 16

Difference between a myopathy and dystrophy

Answer 16

• Dystrophys by definition involve degeneration of muscle (elevated CK usually)
• Myopathy (e.g. Nemaline) don’t exhibit degredation

Question 17

Two clinical signs of muscular dystrophy

Answer 17

• Proximal muscle weakness causes
  1) Gowers’ maneuver
  2) Tredelenberg gait (hip-drop) going up stairs

Question 18

Inheritance pattern of Beckers and Duchenne muscular dystrophy?

Answer 18

X-linked recessive mutation of dystrophin gene

Present in mainly in boys

Question 19

Genetic difference between Duchenne and Becker’s muscular dystrophy

Answer 19

Dystrophin gene (X-linked)

• Becker’s: in-frame deletion (rare)
• Duchenne: deletion leaving rest of protein out of frame