Are you using PowerPoint XP/2002 and above?
For PowerPoint XP/2002 and above, you can.

Try this:
For arrows, use wipe effect. Click on the arrow, then click Slide Show >
Custom Animation.
Click Add Effect > Entrance > Wipe.
Set the direction depending on where the arrowhead is facing.
Note that if you also want to animate the arrowhead, then you will need to
use lines, where you can create two short lines which serve as the arrowhead.

For circle, use Wheel effect.
Select the circle, click Add Effect > Entrance > Wheel.
Set the Spokes to 1.

Holler back if you need more help.