if hypertrophy is your goal then yes, definitely increase the volume. As a general rule, you should do 3-5 sets of 3-5 exercises per bodypart. This is more guideline than rule, so while you would want to do 3-5 exercises a week for your chest, you wouldn't need that many for your arms seeing as they get used so much in pushing/pulling movements. 3 sets of curls/extensions at the end of a session will be fine.
So I figure you mean something like this:
So I figure body parts are organised like Quads, Hamstrings, Chest, Back, Shoulders, Calves, Triceps, Biceps and Abs
Or is it Thighs, Chest, Back, Shoulders, Arms, Calves and Abs?