n1 was the only internal node the textbook talked about, but would the small upside down L shaped node connecting B's node to E1 be considered an internal node? As well as the other upside down L shaped node directly below n1?
I have colored the nodes of your picture (for ease of understanding). A "Node" is considered to be all at the same potential, so you can see that the upside down "L" are at the same potential as "B" and "Z", respectively.
N1 is all by itself (with no external connections) so it is the only internal node.
They are not internal, as they are directly exposed to the inputs/outputs. (The first one is the same as
B input, the second one is the same as