0
votes
1answer
35 views

Contracting muscles in humans

I study biology at school, and unfortunately for me, my program skips the muscles in humans chapter. I know (and mainly, feel) that the movement in one direction isn't created by the same muscle as ...
6
votes
1answer
73 views

Is it the sphincter that flexes when a human pushes a bowel movement?

Of course the sphincter muscle is at the exit point. To use a toothpaste tube analogy, if I want to squeeze out some toothpaste, it does me little to no good to jostle the nozzle; I need to squeeze ...