The Frank Starling law appears to be a trivial observation:
stroke volume is directly related to the end diastolic volume
In everyday language, as more blood fills the heart, the heart pumps more blood out.
Can someone point out whether there are some inaccuracies in the above description because I don't understand why every article on FS law requires upward 20 pages. Even youtube video on this topic is 8 minutes long.
What is the big idea here that I am missing?