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A 16-year old boy participates in a study of exercise and muscle hypertrophy. After a pretraining biopsy specimen of the quadriceps muscle is obtained, he begins a weight-lifting program to increase the mass and strength of the quadriceps muscle. After 3 months of training, a second biopsy is taken. Compared with the pretraining sample, the post-training sample is most likely to show which of the following findings?

Number of Mitochondria / Amount of Actin per Myocyte / Total # of myocytes
A. increase / increase / increase
B. increase / increase / no change
C. increase / no change / increase
D. increase / no change / no change
E. no change / increase / increase
F. no change / increase / no change
G. no change / no change / increase
H. no change / no change / no change


P.S: Kindly Explain 🙂

 

[LuckiestOne]

A 16-year old boy participates in a study of exercise and muscle hypertrophy. After a pretraining biopsy specimen of the quadriceps muscle is obtained, he begins a weight-lifting program to increase the mass and strength of the quadriceps muscle. After 3 months of training, a second biopsy is taken. Compared with the pretraining sample, the post-training sample is most likely to show which of the following findings?

Number of Mitochondria / Amount of Actin per Myocyte / Total # of myocytes
A. increase / increase / increase
B. increase / increase / no change
C. increase / no change / increase
D. increase / no change / no change
E. no change / increase / increase
F. no change / increase / no change
G. no change / no change / increase
H. no change / no change / no change


P.S: Kindly Explain 🙂

I'd say B, because muscle cells don't usually undergo mitosis. Most of the size increase after training come from hypertrophy, but the number of myocytes stay relatively stable. Mitochondria level and actin fiber amount would go up though, because the muscle needs to generate more power to accommodate for the stress you are putting on the body via intensive training