Adding Arrows To Span Class

When using the “<span class=expandall/collapseall>” triggers, I’d like to include the appropriate down or up arrow, that is automatically created when using the [expand] shortcode. If there is syntax I need to add to the “span class” trigger, please let me know, OR if there is an HTML symbol code that matches the arrows, I can add that to the “Expand/Collapse All” text itself.

Thank you in advance for your assistance.