Posted by joseph on .
Muscular dysgenesis or dysgeny is a lethal, recessive, genetic disease of mice that is caused by a mutation in the mdg gene. Skeletal muscles from dysgenic mice are paralyzed and the animals die shortly after birth. You are a research scientist interested in the finding the cause of the cellular defect associated with this genetic disease.
You surgically remove a single muscle fiber from a dysgenic mouse fetus and place it in an experimental chamber in order to study abnormalities in the control of skeletal muscle activity during dysgenesis.
1. Which of the following structures is NOT a part of the muscle fiber?
A. transverse tubule
B. motor end plate
D. synaptic knob
E. sarcoplasmic reticulum
2. You briefly apply a high concentration of acetylcholine (ACh) directly to the motor end plate and observe no contraction of the fiber. Since muscular dysgenesis only affects one type of cell in the body you would suspect that the motor neurons of dysgenic mice work normally. True or False?