The Real Reason for Blisters

I have just put my plants into the flowering stage about a week ago and have noticed blister-like bubbles forming at the internodes. I have read in other post that it is the plant getting ready to pack on weight. I wanted to know is that the real reason or what. I'm the type of person who likes to know the scientific reasoning of things. Any theories or truths will suffice. Thanks ahead of time.

From My Blunt To Yours,
Peace

I've seen this queston asked several times and it happens to some of my plants as well. I think its the plants structure to "beef up" the branches for upcoming bud formations.

I will tell you that all Serious Seeds strains (i've grown) all blister up about 3-4 weeks into the grow. I have yet to have a Serious Seeds strain collapse under weight pressure. Look at my Hempy Grow journal...BIG BUDS

Cant give you a scientific answer...just common sense