"The outer surface of each hair consists of layers of flattened overlapping scales that together form the cuticle. Hair cells contain large deposits of the fibrous protein, keratin. Cuticle cells are little more than tough, dead, keratin-filled scales."
Is "little more" the same as "a little more"?
Is it saying that the number of the living cuticle scales are just a little more than the dead ones?
No: it's saying that there isn't much difference between a cuticle cell and tough, dead, keratin-filled scales. In other words, the author is saying that that is what they are.
"Politicians' promises are little more than hot air." That means that it is very difficult to tell the difference between politicians' promises and hot air.