What is the difference between muscular atrophy, hypertrophy, dystrophy, hypertonia and hypotonia?

Question

This is for a sports ed. (physical education) assignment. im not a science person so simple explanations would be appreciated. Thanks in advance :)

Answer 1

Wow, you don't want much, do you?  ;-)

Okay, here goes.

Muscular atrophy means that muscle that was there has degenerated.  It can happen because of disuse (like if you have a broken bone that's in a cast for a period of time) or because innervation to that muscle has been interrupted (as with a spinal cord injury), or any other reason that it isn't being used.

Hypertrophy is increase in the size or number of muscle cells (myocytes).  You might say that a bodybuilder or someone with overdeveloped muscles in their arms from using a wheelchair demonstrates hypertrophy, but in a pathological sense, you can also see hypertrophy in muscles in children with muscular dystrophy (getting to that).  That happens because of repeated damage to the muscle cells; as long as the body can, it will try to compensate by increasing the size of the remaining cells.

Dystrophy means any condition associated with abnormal development.  It can be due to malnutrition or to genetic disorders like Duchenne or Becker's muscular dystrophy.

Hyper- and hypotonia are, respectively, increase and decrease in overall muscle tone.  You can think of them as spasticity or inability to stretch or a tendency to contract and "floppiness" or looseness of muscle tissue or decreased resistance to movement, respectively.  They can be due to any number of different disorders; they are very general terms.

How's that for a general explanation?