737 wing feature
 

Can any 737 fliers/fixers tell me what the row of little 'things' on the top surface of the wing are for (I've seen them on a 733, not sure if present on other versions), I think they are called vortilons - I've looked on Chris Brady's site and he only mentions the vortilons on the underside of the LE slats. Do the same things on the wing top perform a similar function in reducing the spanwise air flow over the top surface? Hope this isnt a silly question...just curious :)

Thanks! Guess I should've searched the forums first, oops!