Can I upgrade my laptop's graphics card?

I have an HP Pavilion Dv6-1124ca laptop. I'd like to know if the graphics card can either be replaced or if there's a slot for a better, seperate graphics card.

HP EliteBook 8440p Notebook Intel Core i5 460M(2.53GHz) 14" 2GB Memory DDR3 1333 250GB HDD 7200rpm DVD Super Multi Intel HD Graphics

HP EliteBook 8440w Notebook Intel Core i7 640M(2.80GHz) 14" 4GB Memory DDR3 1333 500GB HDD 7200rpm DVD Super Multi NVIDIA Quadro FX 380M

HP Pavilion dv6-3033he NoteBook Intel Core i3 350M(2.26GHz) 15.6" 4GB Memory 500GB HDD 7200rpm DVD Super Multi Intel HD Graphics

HP laptop