Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Muscle Building
Name: Vic
Status: educator
Age: 9-12
Location: OH
Country: N/A
Date: 9/25/2005


Question:
Since muscle cells do not divide, what mechanism is responsible for muscle growth? (ex. - body builders)


Replies:
There are different types and depending on the type of exercise that a person predominantly does certain muscle types will become more dominant. Fast high stress exercise like in ligting heavy weights for short durations will stimulate the increase in the size of white-fast twitch musckle fibers. These muscles fatigue quickly though. On the other hand, if endurance training occurs, red slow twitch fibers which have more mitochondria and smaller bulk will predominate. There is also an intermediate fiber. The amazing adaptions of the body to its environment.

Pf


While you don't make MORE cells, you can make more STUFF inside the cells, called myofibrils. So as Hans und Franz used to say you can "pump up" your cells. Then, if you don't use your muscles they will begin to atrophy. The cells shrink, but you don't lose them.



vanhoeck


Click here to return to the Zoology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory